FLUORINATED TERPHENYLS

Abstract: This invention describes liquid crystal materials of formula (I) which are of particular use in ferroelectric devices: in said formula, R and R' are independently selected from C1-12 alkyl and alkoxy.

Description: Fluorinated Terphenyls The present invention relates to liquid crystal materials, their incorporation in to liquid crystal mixtures or compositions and their use in liquid crystal devices, in particular their use in ferroelectric liquid crystal devices. Materials for use in liquid crystal devices, including ferroelectric devices are the subject of much active research. Liquid crystals can exist in various phases. In essence there are three different classes of liquid crystalline material, each possessing a characteristic molecular arrangement. These classes are nematic, cholesteric and smectic. A wide range of smectic phases exists, for example smectic A (S A ) and smectic C (S c ). Some liquid crystal materials possess a number of liquid crystal phases on varying the temperature, others have just one phase. For example, a liquid crystal material may show the following phases on being cooled from the isotropic phase:- isotropic - nematic - smectic A - smectic C - solid. Most liquid crystal devices incorporate a mixture of materials selected to give desired operating characteristics. The present invention provides liquid crystal materials suitable for incorporating in a wide variety of mixtures to provide the desired characteristics suitable for use in a number of devices, in particularferroelectric liquid crystal devices. Materials for use in ferroelectric liquid crystal devices are assessed on the basis of a number of criteria, these include one or more of the following characteristics: Phase transition temperatures and ordering of liquid crystal phases, viscosity, birefringence, spontaneous polarisation (Ps), dielectric biaxiality. More particularly it is generally preferred that ferroelectric smectic liquid crystal materials possess the following characteristics: low viscosity, a controllable Ps (via use of one or more dopants), an S c phase that persists over a broad temperature range, which preferably includes ambient temperature and exhibits chemical and photochemical stability. Materials which possess these characteristics offer the prospect of very fast switching liquid crystal compositions. Generally a liquid crystal device comprises a layer of liquid crystal material between two cell walls or substrates. Typically the liquid crystal layer is introduced between the cell walls via a narrow gap at an elevated temperature so as to cause it to be in the isotropic, free-flowing phase. At this stage the liquid crystal composition is at a temperature somewhat higher than its operating temperature. The liquid crystal composition is then cooled in a controlled manner until, for a ferroelectric device, an optically active tilted smectic phase is achieved, typically the S c phase (S c * wherein the * indicates chirality or optical activity). Ideally the liquid crystal composition passes through the following phase sequence on cooling: Isotropic (I), Chiral nematic (N*), S A * , S c * . Liquid crystal compositions commonly comprise a so-called host material which generally possesses the required liquid crystal phases and other materials such as dopants which may impart chirality to the mixture and either introduce a Ps or affect the value of an already present Ps. Other so-called additives may be included in the composition such as pitch compensators and dye materials. There are numerous host materials known in the art including fluorinated oligophenyls the subject of PCT/EP88-00724. Fluorinated oligophenyls are also mentioned in PCT/GB93/02422 and PCT/GB94/02693 for use in ferroelectric mixtures. Unpublished GB9719822.0 mentions the use of inter alia fluorinated oligophenyls in mixtures. It has unexpectedly been found by the present inventors that fluorinated terphenyls with the fluorine substituents in a particular substitution pattern result in compounds with inter alia a combination of high dipole moments (more specifically a high lateral dipole) and beneficial phase transitions. According to this invention compounds are provided of general formula I: Formula I wherein R and R' are independently selected from C 1-12 alkyl and alkoxy. Preferably R and R' are selected from the following pairs: R = C 6 H 13 O, R'=C 7 H 15 R = C 6 H 13 O, R'=C 9 H 19 R = C 6 H 13 O, R'=C 1 H 23 R = C 8 H 17 O, R^C-sH^ R = C 8 H 7 O, R'=C 9 H 19 R = C 10 H 21 O, R^CsH^ R = CιoH 21 O, R = C 7 H 15 R = C 0 H 21 O, R'=C 9 H 19 R = OsH-n, R' = C 7 H 15 R = CsHn, R' = C 9 H 9 R = C 7 H 15 , R' = C 9 H 19 R = C 9 H 19 , R' = C 9 H 19 R = C 7 H 15 , R' = CsH^ R = C 7 H 15 , R' = C 7 H 15 R = C 9 H 19 , R' = CsH^ R = C 9 H 9 , R' = C 7 H 15 R = C 6 H 13 0, R' = CsH^ R = CsHn, R' = CsHn R = C 8 H 17 O, R' = C 6 H 13 O R = C 6 H 13 O, R' = C 8 H 17 O R = C 8 H 17 O, R' = C 7 H 15 The invention will be now be described by way of example only with reference to the following drawings of which: Figures 1-18 illustrate synthetic schemes for the synthesis of compounds. Figure 19a illustrates a liquid crystal device operating in a transmissive mode in which the compounds of the current invention may be incorporated. Figure 19b illustrates a liquid crystal device operating in a reflective mode in which the compounds of the current invention may be incorporated. Figure 20 illustrates a binary phase diagram for a mixture of compounds 104 and 105. 2,3-Difluorophenylboronic acid (2) n-Butyllithium (87.6 ml, 0.219 mol) was added to a stirred, cooled (-78 °C) solution of 1 ,2- difluorobenzene (1) (25.00 g, 0.219 mol) in dry THF (300 ml) under a dry nitrogen atmosphere. The mixture was maintained under these conditions for 2.5 h and then trimethyl borate (45.6 g, 49.7 ml, 0.438 mol) was added dropwise at -78 °C. The reaction mixture was allowed to warm to room temperature overnight and then stirred for 1 h with hydrochloric acid (100 ml). The product was extracted into ether, the ethereal extract was washed with water, dried (MgSO4), and the solvent removed in vacuo to yield a colourless solid. Yield: 33.81 g (98%) mp: 220-224 °C 2,3-Difluorophenol (3) Hydrogen peroxide (30% v/v, 150 ml, 44.88 g, 1.32 mol) was added dropwise to a stirred, refluxing solution of 2,3-difluorophenylboronic acid (2) (34.54 g, 0.22 mol) in THF (250 ml). The reaction mixture was heated under reflux overnight, allowed to cool and the product extracted into dichloromethane. The organic extract was washed with brine, dried (MgSO4), and the solvent removed in vacuo. The residue was distilled to give a colourless liquid which crystallised on cooling to yield a colourless crystalline solid. Yield: 23.63 g (83%) mp: 34-36 °C bp: 54-56 °C at 15-25 mmHg 1 H NMR (CDCI3) d: 5.40(1 H, broad, s), 6.65-6.82(2H, m), 6.93(1 H, dddd). IR (KBr) v max /cm- 1 3700-3020. MS (m/z) 130(M + ), 82(100%). 1-Butyloxy-2, 3-difluorobenzene (4) A stirred mixture of 1-bromobutane (16.44 g, 0.120 mol), 2,3-difluorophenol (3) (13.98 g, 0.108 mol) and anhydrous potassium carbonate (44.71 g, 0.324 mol) in butanone (250 ml) was heated under reflux for 24 h. The potassium carbonate was filtered off and the solvent removed in vacuo. The residue was distilled to give a colourless liquid. Yield: 16.30 g (81%) bp: 93-95 °C at 15-25 mmHg 1 H NMR (CDCI3) d: 0.98(3H, t), 1.51 (2H, sext), 1.80(2H, quint), 4.04(2H, t), 6.73(2H, 2 x dddd), 6.95(1 H, dddd). IR v ma χ/cιτr 1 : 1250, 1080. MS (m/z): 186(M + ), 130(100%). 1, 2-Difluoro-3-hexyloxybenzene (5) Quantities: 2,3-difluorophenol (3) (4.70 g, 0.036 mol) 1-bromohexane (7.40 g, 0.045 mol) anhydrous potassium carbonate (18.63 g, 0.135 mol) The experimental procedure was as described for the preparation of compound 4 to give a colourless oil. Yield: 7.30 g (95%) bp: 75-79 °C at 0.1 mmHg 1 H NMR (CDCI3) d: 0.90(3H, t), 1.25-1.55(6H, m), 1.80(2H, quint), 4.00(2H, t), 6.73(2H, 2 x dddd), 6.95(1 H, dddd). IR vmax/cm" 1 : 1250, 1070. MS (m/z): 214(M + ), 43(100%). 1, 2-Difluoro-3-octyloxybenzene (6) Quantities: 2,3-difluorophenol (3) (4.50 g, 0.035 mol) 1-bromooctane (7.72 g, 0.040 mol) anhydrous potassium carbonate (16.56 g, 0.120 mol) The experimental procedure was as described for the preparation of compound 4 to give a colourless oil. Yield: 7.27 g (86%) bp: 92-94 °C at 0.1 mmHg 1 H NMR (CDCI3) d: 0.90(3H, t), 1.20-1.55(10*1, m), 1.80(2H, quint), 4.00(2H, t), 6.73(2H, 2 x dddd), 6.94(1 H, dddd). IR vmaχ/cm- 1 : 1250, 1080. MS (m/z): 242(M + ), 43(100%). 1-Decyloxy-2, 3-difluorobenzene (7) Quantities: 2,3-difluorophenol (3) (9.63 g, 0.074 mol) 1-bromodecane (17.68 g, 0.080 mol) anhydrous potassium carbonate (33.12 g, 0.240 mol) The experimental procedure was as described for the preparation of compound 4 to give a colourless oil. Yield: 16.01 g (80%) bp: 116-118 °C at 0.2 mmHg 1 H NMR (CDCI3) d: 0.88(3H, t), 1.20-1.52(14H, m),1.81 (2H, quint), 4.02(2H, t), 6.67-6.79(2H, 2 x dddd), 6.95(1 H, dddd). IR vmaχ/cnr 1 : 1250, 1080. MS (m/z): 270(M + ), 57(100%). 1-Bromo-2, 3-difluoro-4-hexyloxybenzene (8) A solution of bromine (7.9 ml, 24.49 g, 0.155 mol) in chloroform (30 ml) was added dropwise to a heated (65 °C), stirred solution of 1 ,2-difluoro-3-hexyloxybenzene (5) (13.23 g, 0.062 mol) in chloroform (120 ml). The mixture was maintained at 65 °C for 2 h, allowed to cool to room temperature, quenched with water and washed with 10% w/v sodium metabisulphite solution. The chloroform extract was washed with brine, dried (MgSO4), and the solvent removed in vacuo. The crude product was distilled to give a colourless oil. Yield: 15.89 g (87%) bp: 94-98 °C at 0.15 mmHg 1 H NMR (CDCI3) d: 0.90(3H, t), 1.20-1.55(6H, m), 1.80(2H, quint), 4.00(2H, t), 6.64(1 H, ddd), 7.18(1 H, ddd). IR (KBr) v m aχ/cm- 1 : 1300,1080. MS (m/z): 294(M + ), 292(M + ), 208(100%). 1-Bromo-2, 3-difluoro-4-octyloxybenzene (9) Quantities: 1 ,2-difluoro-3-octyloxybenzene (6) (7.25 g, 0.030 mol) bromine (4.0 ml, 12.0 g, 0.076 mol) The experimental procedure was as described for the preparation of compound 8 to give a colourless oil. Yield: 7.50 g (78%) bp: 114-118 °C at 0.2 mmHg 1 H NMR (CDCI3) d: 0.90(3H, t), 1.20-1.54(10H, m), 1.80(2H, quint), 4.00(2H, t), 6.65(1 H, ddd), 7.18(1 H, ddd). IR v max /cnr 1 : 1300, 1080. MS (m/z): 322(M + ), 320(M + ), 57(100%). 4-Butyloxy-2,3-difluorophenylboronic acid (10) Quantities: 4-butyloxy-2,3-difluorobenzene (4) (16.00 g, 0.086 mol) n-butyllithium (38.0 ml, 0.095 mol) trimethyl borate (17.89 g, 19.66 ml, 0.172 mol) The experimental procedure was as described for the preparation of compound 2 to give a grey solid. Yield: 19.82 g (100%) 2, 3-Difluoro-4-hexyloxyphenylboronic acid (11) Quantities: 1 ,2-difluoro-3-hexyloxybenzene (5) (6.42 g, 0.030 mol) n-butyllithium (13.2 ml, 0.033 mol) trimethyl borate (6.24 g, 6.86 ml, 0.060 mol) The experimental procedure was as described for the preparation of compound 2 to give a white, waxy solid. Yield: 7.18 g (93%) 2,3-Difluoro-4-octyloxyphenylboronic acid (12) Quantities: 1 ,2-difluoro-3-octyloxybenzene (6) (7.33 g, 0.03 mol) n-butyllithium (12.0 ml, 0.030 mol) trimethyl borate (6.24 g, 6.86 ml, 0.060 mol) The experimental procedure was as described for the preparation of compound 2 to give a cream, waxy solid. Yield: 8.32 g (97%) 4-Decyloxy-2,3-difluorophenylboronic acid (13) Quantities: 1-decyloxy-2,3-difluorobenzene (7) (15.80 g, 0.059 mol) n-butyllithium (27.14 ml, 0.068 mol) trimethyl borate (12.27 g, 13.49 ml, 0.118 mol) The experimental procedure was as described for the preparation of compound 2 to give a white, crystalline solid. Yield: 18.53 g (100%) 1-(4-Decyloxy-2, 3-difluorophenyl)-2, 6-dioxaborinane (14) Quantities: 1-decyloxy-2,3-difluorobenzene (7) (20.08 g, 0.074 mol) π-butyllithium (29.60 ml, 0.074 mol) trimethyl borate (22.87 g, 25.13 ml, 0.222 mol) propane-1 ,3-diol (11.40 g, 0.150 mol) The boronic acid (4-decyloxy-2,3-difluorophenylboronic acid) was prepared as described for compound 2 and was used without further purification or isolation, the yield was assumed to be 100%. Propane-1 ,3-diol (11.40 g, 0.150 mol) was added to a stirred suspension of 4-decyloxy- 2,3-difluorophenylboronic acid in petrol (150 ml) and stirred overnight at room temperature. The organic layer was decanted off from the aqueous propane-1 ,3-diol, dried (MgSO4) and the solvent was removed in vacuo to yield a colourless solid. Yield: 25.85 g (99%) 1 H NMR (CDCI3) d: 0.88(3H, t), 1.18-1.52(14H, m), 1.81 (2H, quint), 2.07(2H, quint), 4.04(2H, t), 4.17(4H, 2 x t), 6.69(1 H, ddd), 7.33(1 H, ddd). IR vmaχ/cnr 1 : 1270, 1100. MS (m/z): 354(M + ), 214(100%). 1-(2,3-Difluorophenyl)pentan-1-ol (15) n-Butyllithium (11.4 ml; 10.0 mol dm ~ 3 in hexanes, 0.114 mol) was added dropwise to a stirred, cooled (-78 °C) solution of 1 ,2-difluorobenzene (1) (13.01 g, 0.114 mol) in dry THF (130 ml) under a dry nitrogen atmosphere. The mixture was maintained under these conditions for 2.5 h and a solution of pentanal (8.86 g, 0.103 mol) in dry THF (50 ml) was added dropwise at -78 °C. The mixture was allowed to warm to room temperature overnight and then ammonium chloride solution was added. The product was extracted into ether, washed with water, dried (MgSO4), and the solvent removed in vacuo. The residue was distilled to give a colourless oil. Yield: 15.93 g (77%) bp: 82-86 °C at 0.5 mmHg 1 H NMR (CDCI3) d: 0.89(3H, t), 1.21-1.49(4H, m), 1.65-1.87(2H, m), 2.90(1 H, broad, s), 5.00(1 H, t), 6.98-7.13(2H, m), 7.16-7.25(1 H, m). IR (KBr) v max /cm "1 : 3560-3100, 1050. MS (m/z): 200(M + ), 143(100%). 1-(2, 3-Difluorophenyl)heptan-1-ol (16) Quantities: n-butyllithium (64.0 ml, 0.160 mol) 1 ,2-difluorobenzene (1) (16.55 g, 0.145 mol) heptanal (15.05 g, 0.132 mol) The experimental procedure was as described for the preparation of compound 15. The crude product was purified by gravity column chromatography (silica gel; petrol/ dichloromethane, 1 :1) to give a clear, pale yellow oil. Yield: 21.83 g (73%) 1 H NMR (CDCI3) d: 0.87(3H, t), 1.17-1.50(8H, m), 1.64-1.86(2H, m), 2.21 (1 H, def s), 5.00(11-1, def t), 6.98-7.12(2H, m), 7.15-7.25(1 H, m). IR vmax/crrr 1 : 3600-3100, 1060. MS (m/z): 228(M + ), 143(100%). 1-(2, 3-Difluorophenyl)nonan- 1-ol (17) Quantities: π-butyllithium (56.76 ml, 0.142 mol) 1 ,2-difluorobenzene (1) (14.17 g, 0.129 mol) nonanal (16.61 g, 0.117 mol) The experimental procedure was as described for the preparation of compound 15. The crude product was distilled (bp: 104-108 °C at 0.15 mmHg) to afford a colourless oil which was further purified by gravity column chromatography (silica gel; petrol/ dichloromethane, 1 :1] to give a colourless oil. Yield: 13.70 g (46%) 1 H NMR (CDCI3) d: 0.88(3H, t), 1.17-1.51 (12H, m), 1.65-1.87(2H, m), 2.00(1 H, def s), 5.02(1H, def t), 6.99-7.13(2H, m), 7.16-7.25(1 H, m). IR vmaχ/cnr 1 : 3600-3100. MS (m/z) 256(M + ), 143(100%). 1,2-Difluoro-3-pent-1-enylbenzene (18) A stirred solution of 1-(2,3-difluorophenyl)pentan-1-ol (15) (20.51 g, 0.103 mol) and toluene-4-sulphonic acid (PTSA) (5.00 g) in toluene (250 ml) was heated under reflux in a Dean and Stark apparatus until GLC analysis revealed a complete reaction (3 h). The cooled reaction mixture was poured into a saturated solution of sodium hydrogen carbonate, stirred (1 h), and the product extracted into ether. The ethereal extract was washed with water, dried (MgSO4) and the solvent removed in vacuo. The residue was distilled to give a colourless liquid. Yield: 17.57 g (94%) bp: 96-98 °C at 15-25 mmHg 1 H NMR (CDCI3) d: 0.96(3H, t), 1.51 (2H, sext), 2.22(2H, quart), 6.26-6.40(1 H, dt), 6.51 (11-1, d), 6.91-7.04(2H, m), 7.12-7.22(1 H, m) MS (m/z): 182(M + ), 43(100%). 1, 2-Difluoro-3-pentylbenzene (21 ) Method A Phosphorus pentoxide (25.0 g, 0.176 mol) was added to a stirred solution of 1-(2,3-difluorophenyl)pentan-1-ol (15) (13.00 g, 0.065 mol) in pentane (100 ml). The mixture was stirred at room temperature until GLC analysis revealed a complete reaction. The mixture was then filtered and 5% palladium-on-charcoal (2.00 g) was added to the filtrate. The mixture was stirred overnight under an atmosphere of hydrogen at room temperature (GLC analysis revealed a complete reaction). The palladium catalyst was filtered off, the solvent was removed in vacuo and the product was distilled to give a colourless liquid. Yield: 8.60 g (72%) bp: 82-86 °C at 15-25 mmHg Method B A solution of 1 ,2-difluoro-3-pent-1-enylbenzene (18) (17.39 g, 0.096 mol) and 5% palladium-on-charcoal (2.00 g) in ethanol was stirred overnight under an atmosphere of hydrogen at room temperature (GLC analysis revealed a complete reaction). The palladium-on-charcoal was filtered off, the solvent was removed in vacuo and the product was distilled to give a colourless liquid. Yield: 12.86 g (73%) bp: 82-85 °C at 15-25 mmHg 1 H NMR (CDCI3) d: 0.89(3H, t), 1.25-1.41 (4H, m), 1.61 (2H, quint), 2.65(2H, t), 6.88-7.03(3H, m) MS (m/z) 184(M + ), 127(100%). 1, 2-Difluoro-3-heptylbenzene (22) A stirred solution of 1-(2,3-difluorophenyl)heptan-1-ol (16) (19.67 g, 0.086 mol) and PTSA (5.00 g) in toluene (250 ml) was heated under reflux in a Dean and Stark apparatus until GLC analysis revealed a complete reaction (3 h). The cooled reaction mixture was poured into a saturated solution of sodium hydrogen carbonate, stirred (1 h), and the product was extracted into ether. The ethereal extract was washed with water, dried (MgSO4) and the solvent removed in vacuo. The residue was dissolved in ethanol (250 ml) and hydrogenated overnight at room temperature and pressure using 5% palladium- on-charcoal (2.00 g) (GLC analysis revealed a complete reaction). The palladium catalyst was filtered off, the solvent was removed in vacuo and the product distilled to give a colourless oil. Yield: 14.22 g (78%) bp: 124-126 °C at 15-25 mmHg 1 H NMR (CDCI3) d: 0.90(3H, t), 1.15-1.39(8H, m), 1.60(2H, quint), 2.65(2H, t), 6.92-7.00(3H, m). MS (m/z): 212(M + ), 128(100%). 1, 2-Difluoro-3-nonylbenzene (23) Quantities: 1-(2,3-difluorophenyl)nonan-1-ol (17) (12.84 g, 0.050 mol) PTSA (5.00 g) 5% palladium on charcoal (2.00 g) The experimental procedure was as described for the preparation of compound 22 to give a colourless oil. Yield: 8.51 g (71%) bp: 72-74 °C at 0.1 mmHg 1 H NMR (CDCI3) d: 0.90(3H, t), 1.20-1.40(12H, m), 1.60(2H, quint), 2.65(2H, t), 6.92-7.00(3H, m). MS (m/z): 240(M + ). 2,3-Difluoro-4-pentylphenylboronic acid (24) Quantities: 1 ,2-difluoro-3-pentylbenzene (21) (8.00 g, 0.043 mol) π-butyllithium (17.4 ml, 0.043 mol) trimethyl borate (9.00 g, 9.84 ml, 0.087 mol) The experimental procedure was as described for the preparation of compound 2 to give a white, crystalline solid. Yield: 8.79 g (90%) 2, 3-Difluoro-4-heptylphenylboronic acid (25) Quantities: 1 ,2-difluoro-3-heptylbenzene (22) (14.00 g, 0.066 mol) π-butyllithium (29.06 ml, 0.073 mol) trimethyl borate (13.73 g, 15.09 ml, 0.132 mol) The experimental procedure was as described for the preparation of compound 2 to give a cream semi-solid. Yield: 16.89 g (100%) 2,3-Difluoro-4-nonylphenylboronic acid (26) Quantities: 1 ,2-difluoro-3-nonylbenzene (23) (8.50 g, 0.035 mol) π-butyllithium (15.40 ml, 0.039 mol) trimethyl borate (7.28 g, 8.00 ml, 0.070 mol) The experimental procedure was as described for the preparation of compound 2 to give a cream, crystalline solid. Yield: 9.60 g (97%) 1-Bromo-4-hexyloxybenzene (28) Quantities: 4-bromophenol (27) (14.0 g, 0.081 mol) 1-bromohexane (14.85 g, 0.090 mol) anhydrous potassium carbonate (33.53 g, 0.243 mol) The experimental procedure was as described for the preparation of compound 4 to give a colourless oil. Yield: 19.26 g (93%) bp: 135-137 °C at 0.2 mmHg 1 H NMR (CDCI3) d: 0.90(3H, t), 1.25-1.50(6H, m), 1.75(2H, quint), 3.85(2H, t), 6.74(2H, d), 7.33(2H, d). IR (KBr) v m ax/cm-1 : 1240. MS (m/z): 258(M + ), 256(M + ), 174(100%). 1-Bromo-4-octyloxybenzene (29) Quantities: 4-bromophenol (27) (12.11 g, 0.070 mol) 1-bromooctane (20.27 g, 0.105 mol) anhydrous potassium carbonate (43.47 g, 0.315 mol) The experimental procedure was as described for the preparation of compound 4 to give a colourless oil. Yield: 19.38 g (97%) bp: 145-146 °C at 0.1 mmHg 1 H NMR (CDCI3) d: 0.90(3H, t), 1.20-1.50(10H, m), 1.75(2H, quint), 3.90(2H, t), 6.75(2H, d), 7.35(2H, d). IR max/crrr : 1240. MS (m/z): 286(M + ), 284(M + ), 174(100%), 172(100%). 4-Octyloxyphenylboronic acid (30) Quantities: 1-bromo-4-octyloxybenzene (29) (10.00 g, 0.035 mol) π-butyllithium (15.6 ml, 0.039 mol) trimethyl borate (7.28 g, 8.00 ml, 0.070 mol) The experimental procedure was as described for the preparation of compound 2 to give a cream coloured solid. Yield: 8.62 g (99%) Undecanoyl chloride (32) A solution of oxalyl chloride (25.00g, 0.197 mol) in dry dichloromethane (50 ml) was added dropwise to a stirred solution of undecanoic acid (31) (24.40 g, 0.131 mol) and dry DMF (40 drops) in dry dichloromethane (500 ml) at room temperature. The mixture was stirred at room temperature overnight and the excess of oxalyl chloride and dichloromethane were removed in vacuo. The residue was distilled to give a colourless oil which was used without further purification. Yield: 21.13 g (79%) bp: 120-122 °C at 15-25 mmHg 1-Bromo-4-pentanoylbenzene (34) Pentanoyl chloride (50.0 g, 0.41 mol) was added dropwise to a stirred, cooled (0 °C) mixture of bromobenzene (33) (150 ml) and anhydrous aluminium chloride (62.0 g, 0.46 mol). The resulting mixture was stirred at 0 °C for 1 h, heated at 80 °C for 2 h, cooled and poured into hydrochloric acid. The product was extracted into chloroform, the chloroform extract was washed with water and steam distilled (to remove chloroform and the excess bromobenzene). The residue was extracted into chloroform, the chloroform extract washed with water, dried (MgSO4) and the solvent was removed in vacuo. The residue was distilled to yield a colourless crystalline solid. Yield: 90.71 g (92%) bp: 180-184 °C at 15-25 mmHg 1 H NMR (CDCI3) d: 0.95(3H, t), 1.40(2H, sext), 1.70(2H, quint), 2.92(2H, t), 7.58(2H, d), 7.81(2H, d). MS (m/z): 242(M + ), 240(M + ), 183(100%). 1-Bromo-4-heptanoylbenzene (35) Quantities: heptanoyl chloride (60.0 g, 0.40 mol) bromobenzene (33) (150 ml) aluminium chloride (62.0 g, 0.46 mol) The experimental procedure was as described for the preparation of compound 34 however, the crude product was not distilled under reduced pressure but was recrystallised from ethanol/ethyl acetate (1 :1) to yield colourless crystals. Yield: 85.08 g (79%) mp: 69-72 °C 1 H NMR (CDCI3) d: 0.89(3H, t), 1.24-1.44(6H, m), 1.72(2H, quint), 2.92(2H, t), 7.59(2H, d), 7.82(2H, d). IR vmax/cm "1 : 1670. MS (m/z): 270(M + ), 268(M + ), 185(100%). 1-Bromo-4-nonanoylbenzene (36) Quantities: nonanoyl chloride (59.4 g, 0.336 mol) bromobenzene (33) (150 ml) aluminium chloride (50.7 g, 0.38 mol) The experimental procedure was as described for the preparation of compound 34 however, the crude product was not distilled under reduced pressure but was recrystailised from ethanol/ethyl acetate (1:1) to yield colourless crystals. Yield: 75.16 g (75%) mp: 68-69.5 °C 1 H NMR (CDCI3) d: 0.88(3H, t), 1.17-1.44(10H, m), 1.72(2H, quint), 2.92(2H, t), 7.59(2H, d), 7.82(2H, d). IR v m aχ/cm- 1 : 1670. MS (m/z) 298(M + ), 296(M + ), 200(100%), 198(100%). 1-Bromo-4-undecanoylbenzene (37) Quantities: undecanoyl chloride (25.0 g, 0.122 mol) bromobenzene (33) (150 ml) aluminium chloride (18.73 g, 0.140 mol) The experimental procedure was as described for the preparation of compound 34 to give a colourless oil. Yield: 22.27 g (67%) 1 H NMR (CDCI3) d: 0.87(3H, t), 1.18-1.44(14H, m), 1.72(2H, quint), 2.91 (2H, t), 7.59(2H, d), 7.82(2H, d). MS (m/z) 326(M + ), 324(M + ), 198(100%). 1-Bromo-4-pentylbenzene (38) A stirred mixture of 1-bromo-4-pentanoylbenzene (34) (90.45 g, 0.375 mol) and hydrazine hydrate (36.06 g, 1.125 mol) in diethylene giycol (350 ml) was heated to 130 °C at which point water and excess hydrazine hydrate were distilled off. The solution was allowed to cool to below 60 °C and potassium hydroxide (63.12 g, 1.125 mol) was added with stirring. The stirred solution was heated at 200 °C for 2 h, cooled and poured into a mixture of crushed ice and concentrated hydrochloric acid. The product was extracted into dichloromethane, the dichloromethane extract was washed with water, dried (MgSO4) and the solvent was removed in vacuo. The residue was distilled to give a colourless oil. Yield: 76.60 g (90%) bp: 124-128 °C at 15-25 mmHg 1 H NMR (CDCI3) d: 0.88(3H, t), 1.21-1.40(4H, m), 1.57(2H, quint), 2.54(2H, t), 7.03(2H, d), 7.37(2H, d). MS (m/z): 228(M + ), 226(M + ), 171(100%). 1-Bromo-4-heptylbenzene (39) Quantities: 1-bromo-4-heptanoylbenzene (35) (85.00 g, 0.316 mol) hydrazine hydrate (30.38 g, 0.948 mol) potassium hydroxide (53.19 g, 0.948 mol) The experimental procedure was as described for the preparation of compound 38 to give a colourless liquid. Yield: 69.68 g (90%) bp: 112-115 °C at 0.1 mmHg 1 H NMR (CDCI3) d: 0.88(3H, t), 1.20-1.40(8H, m), 1.57(2H, quint), 2.54(2H, t), 7.03(2H, d), 7.37(2H, d). MS (m/z): 256(M + ), 254(M + ), 169(100%). 1-Bromo-4-nonylbenzene (40) Quantities: 1-bromo-4-nonanoylbenzene (36) (74.55 g, 0.251 mol) hydrazine hydrate (24.13 g, 0.753 mol) potassium hydroxide (42.25 g, 0.753 mol) The experimental procedure was as described for the preparation of compound 38 to give a colourless oil. Yield: 57.01 g (80%) bp: 114-118 °C at 0.2 mmHg 1 H NMR (CDCI3) d: 0.88(3H, t), 1.16-1.40(12H, m), 1.56(2H, quint), 2.54(2H, t), 7.03(2H, d), 7.37(2H, d). MS (m/z) 284(M + ), 282(M + ), 171(100%), 169(100%). 1-Bromo-4-undecylbenzene (41 ) Quantities: 1-bromo-4-decanoyibenzene (37) (22.08 g, 0.068 mol) hydrazine hydrate (6.54 g, 0.204 mol) potassium hydroxide (11.45 g, 0.204 mol) The experimental procedure was as described for the preparation of compound 38 to give a colourless oil. Yield: 13.11 g (62%) bp: 132-138 °C at 0.01 mmHg 1 H NMR (CDCI3) d: 0.87(3H, t), 1.15-1.39(16H, m), 1.57(2H, quint), 2.55(2H, t), 7.03(2H, d), 7.37(2H, d). MS (m/z): 312(M + ), 310(M + ), 91 (100%). 4-Pentylphenylboronic acid (42) Quantities: 1-bromo-4-pentylbenzene (38) (30.00 g, 0.132 mol) n-butyllithium (58.15 ml, 0.145 mol) trimethyl borate (27.46 g, 30.17 ml, 0.264 mol) The experimental procedure was as described for the preparation of compound 2 to give a cream soft-solid. Yield: 25.30 g (100%) 4-Heptylphenylboronic acid (43) Quantities: 1-bromo-4-heptylbenzene (39) (30.0 g, 0.122 mol) π-butyllithium (53.68 ml, 0.134 mol) trimethyl borate (25.38 g, 27.89 ml, 0.244 mol) The experimental procedure was as described for the preparation of compound 2 to give a cream semi-solid. Yield: 22.26 g (100%) 4-Nonylphenylboronic acid (44) Quantities: 1-bromo-4-nonylbenzene (40) (30.0 g, 0.106 mol) π-butyllithium (46.8 ml, 0.117 mol) trimethyl borate (22.05 g, 24.2 ml, 0.212 mol) The experimental procedure was as described for the preparation of compound 2 to give a white, waxy solid. Yield: 25.39 g (97%) 4-Undecylphenylboronic acid (45) Quantities: 1-bromo-4-undecylbenzene (41) (12.00 g, 0.039 mol) π-butyllithium (17.16 ml; 2.5 mol dm ~ 3 in hexane, 0.043 mol) trimethyl borate (8.11 g, 8.91 ml, 0.078 mol) The experimental procedure was as described for the preparation of compound 2 to give a cream solid. Yield: 10.33 g (96%) 1-(4-Pentylphenyl)-2, 6-dioxaboήnane (46) Quantities: 1-bromo-4-pentylbenzene (38) (20.00 g, 0.088 mol) π-butyllithium (35.20 ml, 0.088 mol) trimethyl borate (27.29 g, 29.99 ml, 0.264 mol) propane-1 ,3-diol (12.90 g, 0.170 mol) The experimental procedure was as described for the preparation of compound 14 to give a colourless oil which crystallised on standing over a long period of time to yield very soft, low melting, colourless crystals which were dried in vacuo (P2O5). Yield: 16.60 g (81%) 1 H NMR (CDCI3) d: 0.85(3H, t), 1.25-1 ,40(4H, m), 1.60(2H, quint), 2.03(2H, quint), 2.59(2H, t), 4.14(41-1, 2 x t), 7.15(2H, d), 7.67(2H, d). MS (m/z) 232(M + ), 175(100%). 1-(4-Heptylphenyl)-2, 6-dioxaboήnane (47) Quantities: 1-bromo-4-heptylbenzene (39) (20.00 g, 0.079 mol) π-butyllithium (31.60 ml, 0.079 mol) trimethylborate (24.72 g, 27.16 ml, 0.240 mol) propane-1 ,3-diol (12.16 g, 0.160 mol) The experimental procedure was as described for the preparation of compound 14 to give a colourless oil. Yield: 25.85 g (99%) 1 H NMR (CDCI3) d: 0.87(3H, t), 1.17-1.41 (8H, m), 1.60(2H, quint), 2.03(2H, quint), 2.60(2H, t), 4.14(4H, 2 x t), 7.16(2H, d), 7.67(2H, d). MS (m/z): 260(M + ), 43(100%). 4-Bromo-2-fluoro-1-hexyloxybenzene (49) Quantities: 4-bromo-2-fluorophenol (48) (11.45 g, 0.060 mol) 1-bromohexane (11.55 g, 0.070 mol) anhydrous potassium carbonate (28.98 g, 0.210 mol) The experimental procedure was as described for the preparation of compound 4 to give colourless oil. Yield: 16.09 g (98%) bp: 96-98 °C at 0.3 mmHg 1 H NMR (CDCI3) d: 0.90(3H, t), 1.25-1.50(6H, m), 1.80(2H, quint), 4.00(2H, t), 6.82(1 H, dd), 7.16(11-1, ddd), 7.22(1 H, dd). IR max/cm "1 : 1260. MS (m/z) 276(M + ), 274(M + ). 4-Bromo-2-fluoro-1-octyloxybenzene (50) Quantities: 4-bromo-2-fluorophenol (48) (25.00 g, 0.130 mol) 1-bromooctane (38.40 g, 0.200 mol) anhydrous potassium carbonate (82.80 g, 0.6 mol) The experimental procedure was as described for the preparation of compound 4 to give a colourless oil. Yield: 36.52 g (93%) bp: 118-121 °C at 0.1 mmHg 1 H NMR (CDCI3) d: 0.88(3H, t), 1.17-1.52(10H, m), 1.80(2H, quint), 3.98(2H, t), 6.82(1 H, dd), 7.16(1 H, ddd), 7.22(1 H, dd). MS (m/z): 304(M + ), 302(M + ), 192(100%). 3-Fluoro-4-hexyloxyphenylboronic acid (51) Method A Quantities: 4-bromo-2-fluoro-1-hexyloxybenzene (49) (8.00 g, 0.029 mol) π-butyllithium (12.76 ml, 0.032 mol) trimethyl borate (6.03 g, 6.63 ml, 0.058 mol) The experimental procedure was as described for the preparation of compound 2 to give a cream solid. Yield: 6.89 g (99%) Method B A 20% portion of a solution of 4-bromo-2-fluoro-1-hexyloxybenzene (49) (8.83 g, 0.032 mol) in dry THF (50 ml) was added to a mixture of magnesium turnings (0.87 g, 0.036 mol) and 1 ,2-dibromoethane (2-3 drops) in dry THF (10 ml) under dry nitrogen. The reaction mixture was heated gently until the mixture became cloudy and the solvent began to boil without the need for external heat. The remainder of the 4-bromo-2-fluoro-1- hexyloxybenzene solution was added dropwise whilst maintaining a gentle reflux. The reaction mixture was heated under reflux for a further 45 min after the addition was completed (GLC analysis revealed a complete reaction) and cooled to -78 °C. Trimethyl borate (6.66 g, 7.23 ml, 0.064 mol) was added dropwise and the reaction mixture was allowed to warm to room temperature overnight. Hydrochloric acid (100 ml) was added and the mixture was stirred at room temperature for 1 h. The product was extracted into ether, the ethereal extract was washed with brine, dried (MgSO4), and the solvent was removed in vacuo to give a cream solid. Yield: 7.48 g (97%) 2-Fluoro-4-iodoaniline (53) Course powdered iodine (500 g, 1.97 mol) was added, in portions, to a stirred mixture of 2-fluoroaniline (52) (353 g, 3.18 mol) and sodium hydrogen carbonate (260 g, 3.10 mol) in water (800 ml) at 60-80 °C. The mixture was maintained at this temperature for a further 2 h before being poured onto ice and left to cool overnight. The water and the residual oil were decanted from the solid product and discarded. The solid product was dissolved in ether, washed with water, dried (MgSO4) and the solvent was removed in vacuo. The residue was recrystallised from cyclohexane to yield purple-tinted crystals. Yield: 359.79 g (77% based on iodine) mp: 52-54 °C 1 H NMR (CDCI3) d: 3.55(2H, broad s), 6.52(1 H, dd), 7.20(1 H, ddd), 7.27(1 H, dd). IR (KBr) vmax /cm" 1 : 3500-2200, 3400, 3320. MS (m/z) 237(M + , 100%). 1-Bromo-2-fluoro-4-iodobenzene (54) A solution of sodium nitrite (22.77 g, 0.33 mol) in water (40 ml) was added dropwise to a stirred, cooled (0 °C) suspension of 2-fluoro-4-iodoaniline (53) (70.0 g, 0.30 mol) in hydrobromic acid (48% w/v, 200 ml). The solution was stirred at 0 °C for 30 min and then added in portions to a stirred, boiling solution of copper(l) bromide (50.0 g, 0.35 mol) in hydrobromic acid (48% w/v, 100 ml). The stirred mixture was boiled for a further 15 min and left to cool overnight. Water was added and the product extracted into ether, the ethereal extract was washed with water, 10% w/v sodium hydroxide solution and water and then dried (MgSO4). The solvent was removed in vacuo and the residue was distilled (bp: 108-112 °C at 15-25 mmHg) to give a pale pink, crystalline solid. The product was further purified by gravity column chromatography (silica gel; hexane) to yield a colourless crystalline solid. Yield: 58.62 g (65%) mp: 37-38 °C 1 H NMR (CDCI3) d: 7.26(1 H, dd), 7.35(1 H, ddd), 7.46(1 H, dd). MS (m/z): 302(M + ), 300(M + ), 93(100%). 1-Bromo-2-fluoro-4-pent-1-ynylbenzene (55) A solution of π-butyllithium (32.56 ml, 0.081 mol) was added dropwise to a stirred, cooled (-5 °C to 0 °C) solution of pent-1-yne (5.00 g, 0.074 mol) in dry THF (100 ml) under a dry nitrogen atmosphere. The mixture was stirred for 10 min (at -5 °C to 0 °C) and then a solution of anhydrous zinc chloride (12.15 g, 0.089 mol) in dry THF (100 ml) was added dropwise at -5 °C to 0 °C and the mixture was then stirred at room temperature for 15 min. A solution of 1-bromo-2-fluoro-4-iodobenzene (54) (18.66 g, 0.062 mol) in dry THF (50 ml) was added dropwise to the cooled mixture (-5 °C to 0°C) followed by the addition of tetrakis(triphenylphosphine)palladium(0) (3.58 g, 3.10 mmol). The mixture was stirred at room temperature overnight (GLC analysis revealed a complete reaction) and poured into hydrochloric acid. The product was extracted into ether, the ethereal extract was washed with aqueous sodium hydrogen carbonate, dried (MgSO4) and the solvent was removed in vacuo. The resultant orange liquid was filtered through a short alumina column eluted with dichloromethane, the solvent removed in vacuo and the residue was distilled to give a colourless oil Yield: 9.96 g (67%) bp: 128-132 °C at 15-25 mmHg H NMR (CDCI3) d: 1.03(3H, t), 1.62(2H, sext), 2.36(2H„ t), 7.04(1 H, ddd), 7.13(1 H, dd), 7.43(1 H, dd). MS (m/z): 242(M + , 100%), 240(M + ). 1 -Bromo-2-fluoro-4-hept- 1 -ynylbenzene (56) Quantities: hept-1-yne (5.19 g, 0.054 mol) π-butyllithium (24.0 ml, 0.060 mol) zinc chloride (9.00 g, 0.066 mol) 1-bromo-2-fluoro-4-iodobenzene (54) (13.55 g, 0.045 mol) tetrakis(triphenylphosphine)palladium(0) (2.60 g, 2.25 mmol) The experimental procedure was as described for the preparation of compound 55 to give a colourless oil. Yield: 7.93 g (66%) bp: 112-114 °C at 0.5 mmHg 1 H NMR (CDCI3) d: 0.92(3H, t), 1.27-1.48(4H, m), 1.60(2H, quint), 2.38(2H, t), 7.04(1 H, ddd), 7.13(1 H, dd), 7.44(1 H, dd). MS (m/z) 270(M + , 100%), 268(M + , 100%). 1-Bromo-2-fluoro-4-non-1-ynylbenzene (57) Quantities: non-1-yne (6.11 g, 0.049 mol) π-butyllithium (21.6 ml, 0.054 mol) zinc chloride (8.18 g, 0.060 mol) 1-bromo-2-fluoro-4-iodobenzene (54) (12.34 g, 0.041 mol) tetrakis(triphenylphosphine)palladium(0) (2.37 g, 2.05 mmol) The experimental procedure was as described for the preparation of compound 55 to give a colourless oil. Yield: 7.91 g (65%) bp: 122-124 °C at 0.2 mmHg 1 H NMR (CDCI3) d: 0.89(3H, t), 1.22-1.50(6H, m), 1.59(2H, quint), 2.39(2H, t), 7.03(1H, ddd), 7.12(1 H, d), 7.43(1H, dd). MS (m/z) 298(M + ), 296(M + ), 147(100%). 1-Bromo-2-fluoro-4-pentylbenzene (58) Quantities: 1-bromo-2-fluoro-4-pent-1-ynylbenzene (55) (9.70 g, 0.040 mol) platinum(IV) oxide (0.30 g) The experimental procedure was as described for the preparation of compound 21 (Method B). The platinum(IV) oxide was filtered off and the solvent removed in vacuo. The residue was distilled to give a colourless liquid. Yield: 8.04 g (83%) bp: 80-84 °C at 0.5 mmHg 1 H NMR (CDCI3) d: 0.89(3H, t), 1.22-1.41 (4H, m), 1.59(2H, quint), 2.56(2H, t), 6.84(1 H, ddd), 6.94(1 H, dd), 7.41 (1 H, dd). MS (m/z): 246(M + ), 244(M + ), 108(100%). 1-Bromo-2-fluoro-4-heptylbenzene (59) Quantities: 1-bromo-2-fluoro-4-hept-1-ynylbenzene (56) (7.74 g, 0.029 mol) platinum(IV) oxide (0.25 g) The experimental procedure was as described for the preparation of compound 21 (Method B). The platinum(IV) oxide was filtered off and the solvent removed in vacuo. The residue was distilled to give a colourless oil. Yield: 7.23 g (91%) bp: 102-105 °C at 0.4 mmHg 1 H NMR (CDCI3) d: 0.88(3H, t), 1.20-1.38(8H, m), 1.58(2H, quint), 2.56(2H, t), 6.83(1 H, ddd), 6.93(1 H, dd), 7.40(1 H, dd). MS (m/z): 274(M + ), 272(M + ), 109(100%). 1-Bromo-2-fluoro-4-nonylbenzene (60) Quantities: 1-bromo-2-fluoro-4-non-1-ynylbenzene (57) (7.70 g, 0.026 mol) platinum(IV) oxide (0.25 g) The experimental procedure was as described for the preparation of compound 21 (Method B) except the solvent used in the reaction was a 1 :1 mixture of ethanol and THF. The platinum(IV) oxide was filtered off and the solvent removed in vacuo. The residue was distilled to give a colourless oil. Yield: 6.78 g (87%) bp: 125-127 °C at 0.5 mmHg 1 H NMR (CDCI3) d: 0.88(3H, t), 1.19-1.38(12H, m), 1.58(2H, quint), 2.56(2H, t), 6.83(1 H, ddd), 6.94(1 H, dd), 7.41 (1 H, dd). MS (m/z): 302(M + ), 300(M + ), 188(100%). 4-Bromo-2-fluoro-1-pent-1-ynylbenzene (62) Quantities: pent-1-yne (5.00 g, 0.074 mol) π-butyllithium (32.56 ml, 0.081 mol) zinc chloride (12.15 g, 0.089 mol) 4-bromo-2-fluoro-1-iodobenzene (61) (18.66 g, 0.062 mol) tetrakis(triphenylphosphine)palladium(0) (3.58 g, 3.10 mmol) The experimental procedure was as described for the preparation of compound 55 to give a colourless oil. Yield: 9.99 g (67%) bp: 124-128 °C at 15-25 mmHg 1 H NMR (CDCI3) d: 1.05(3H, t), 1.64(2H, sext), 2.41 (2H, t), 7.17-7.28(3H, m). MS (m/z): 242(M + ), 240(M + ), 145(100%). 4-Bromo-2-fluoro-1-pentylbenzene (63) Quantities: 4-bromo-2-fluoro-1-pent-1-ynylbenzene (62) (9.40 g, 0.039 mol) platinum(IV) oxide (0.30 g) The experimental procedure was as described for the preparation of compound 21 (Method B). The platinum(IV) oxide was filtered off, the solvent was removed in vacuo and the residue distilled to give a colourless liquid. Yield: 8.30 g (87%) bp: 115-117 °C at 15-25 mmHg 1 H NMR (CDCI3) d: 0.89(3H, t), 1.22-1.41 (4H, m), 1.57(2H, quint), 2.57(2H, t), 7.04(1 H, dd), 7.14-7.22(2H, m). MS (m/z) 246(M + ), 244(M + ), 189(100%). 3-Fluoro-4-pentylphenylboronic acid (64) Quantities: 4-bromo-2-fluoro-1-pentylbenzene (63) (12.50 g, 0.051 mol) π-butyllithium (22.4 ml, 0.056 mol) trimethyl borate (10.61 g, 11.66 ml, 0.102 mol) The experimental procedure was as described for the preparation of compound 2 to give a cream coloured, waxy solid. Yield: 10.12 g (94%) 4 '-Bromo-3-fluoro-4-pentylbiphenyl (66) Tetrakis(triphenylphosphine)palladium(0) (0.75 g, 0.65 mmol) and 3-fluoro-4- pentylphenylboronic acid (64) (3.06 g, 0.015 mol) were added sequentially to a stirred mixture of 1-bromo-4-iodobenzene (65) (3.73 g, 0.013 mol), sodium carbonate (40.0 ml, 2 mol dm " 3) and 1 ,2-dimethoxyethane (40 ml) under a dry nitrogen atmosphere. The mixture was heated under reflux until GLC analysis revealed a complete reaction. The cooled mixture was poured into water and the product extracted into ether. The ethereal extract was washed with brine, dried (MgSO4) and the solvent was removed in vacuo. The crude product was purified by gravity column chromatography (silica gel; hexane) to give a colourless liquid which was further purified by Kugelrohr distillation (175 °C at 0.2 mmHg) to give a colourless oil. Yield: 2.08 g (50%) 1 H NMR (CDCI3) d: 0.89(3H, t), 1.20-1.45(4H, m), 1.60(2H, quint), 2.65(2H, t), 7.15-7.27(3H, m), 7.41(2H, d), 7.54(2H, d). MS (m/z) 322(M + ), 320(M + ). 4'-Bromo-3-fluoro-4-hexyloxybiphenyl (67) Quantities: 3-fluoro-4-hexyloxyphenylboronic acid (51) (6.51 g, 0.020 mol) 1-bromo-4-iodobenzene (65) (4.81 g, 0.017 mol) tetrakis(triphenylphosphine)palladium(0) (0.98 g, 0.85 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless solid which was recrystallised from ethanol to yield colourless crystals. Yield: 3.57 g (60%) mp: 63-64.5 °C 1 H NMR (CDCI3) d: 0.91 (3H, t), 1.29-1.55(6H, m), 1.84(2H, quint), 4.06(2H, t), 7.00(1 H, dd), 7.24(1 H, ddd), 7.28(1 H, dd), 7.38(2H, d), 7.53(2H, d). MS (m/z) 352(M + ), 350(M + ), 268(100%). 4-Bromo-3-fluoro-4 '-pentylbiphenyl (68) Quantities: 4-pentylphenylboronic acid (42) (6.59 g, 0.034 mol) 1-broιmo-2-fluoro-4-iodobenzene (54) (9.39 g, 0.031 mol) tetrakis(triphenylphosphine)palladium(0) (1.80 g, 1.56 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless liquid which was further purified by Kugelrohr distillation (150 °C at 0.2 mmHg) to give a colourless oil. Yield: 3.48 g (35%) H NMR (CDCI3) d: 0.90(3H, t), 1.25-1.44(4H, m), 1.64(2H, quint), 2.64(2H, t), 7.19-7.29(3H, m), 7.33(1 H, dd), 7.45(2H, d), 7.56(1 H, dd). MS (m/z): 322(M + ), 320(M + ), 147(100%). 3-Fluorophenylboronic acid (70) Quantities: 1-bromo-3-fluorobenzene (69) (21.08 g, 0.12 mol) magnesium turnings (3.40 g, 0.14 mol) trimethyl borate (24.72 g, 27.46 ml, 0.240 mol) The experimental procedure was as described for the preparation of compound 51 (Method B) to give a colourless solid. Yield: 16.61 g (99%) 3-Fluoro-4 '-heptylbiphenyl (71 ) Quantities: 4-heptylphenylboronic acid (43) (10.00 g, 0.046 mol) 1-bromo-3-fluorobenzene (69) (8.00 g, 0.046 mol) tetrakis(triphenylphosphine)palladium(0) (2.60 g, 2.30 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless liquid which was further purified by Kugelrohr distillation (160 °C at 0.2 mmHg) to yield a colourless oil. Yield: 5.56 g (45%) 1 H NMR (CDCI3) d: 0.88(3H, t), 1.21-1.40(8H, m), 1.64(2H, quint), 2.64(2H, t), 6.95-7.04(1 H, m), 7.20-7.31 (3H, m), 7.32-7.40(2H, m), 7.48(2H, d). MS (m/z): 270(M + ), 91(100%). 3-Fluoro-4 '-hexyloxybiphenyl (72) Quantities: 3-fluorophenylboronic acid (70) (3.92 g, 0.028 mol) 1-bromo-4-hexyloxybenzene (28) (2.33 g, 6.44 mmol) tetrakis(triphenylphosphine)palladium(0) (1.27 g, 1.10 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol/ dichloromethane, 4:1) to yield a colourless solid. Yield: 4.99 g (83%) mp: 33-34 °C 1 H NMR (CDCI3) d: 0.90(3H, t), 1.25-1.54(6H, m), 1.80(2H, quint), 4.00(2H, t), 6.92-7.02(3H, m), 7.23(1 H, ddd), 7.29-7.40(2H, m), 7.49(2H, d). IR (KBr) vmaχ/cm- 1 : 1245. MS (m/z): 272(M + ), 189(100%). 3-Fluoro-4 '-octyloxybiphenyl (73) Quantities: 4-octyloxyphenylboronic acid (30) (6.25 g, 0.025 mol) 1-bromo-3-fluorobenzene (69) (3.50 g, 0.020 mol) tetrakis(triphenylphosphine)palladium(0) (1.20 g, 1.00 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol/ dichloromethane, 7:3) to give a colourless solid which was recrystallised from ethanol to yield colourless crystals. Yield: 4.52 g (75%) mp: 42-43.5 °C 1 H NMR (CDCI3) d: 0.89(3H, t), 1.20-1.55(10H, m), 1.80(2H, quint), 4.00(2H, t), 6.90-7.02(3H, m), 7.24(1 H, ddd), 7.29-7.40(2H, m), 7.49(2H, d). IR (KBr) vmaχ/cm- 1 : 1260. MS (m/z): 300(M + ), 188(100%). 3-Fluoro-4'-heptylbiphenyl-4-ylboronic acid (74) Quantities: 3-fluoro-4'-heptylbiphenyl (71) (5.40 g, 0.020 mol) sec-butyllithium (17.69 ml; 1.3 mol dm'3 jn cyclohexane, 0.023 mol) trimethyl borate (4.78 g, 5.25 ml, 0.046 mol) The experimental procedure was as described for the preparation of compound 2 to give a cream, waxy solid. Yield: 6.22 g (99%) 3-Fluoro-4'-hexyloxybiphenyl-4-ylboronic acid (75) Quantities: 3-fluoro-4'-hexyloxybiphenyl (72) (4.97 g, 0.018 mol) sec-butyllithium (15.92 ml; 1.3 mol dm~3 jn cyclohexane, 0.021 mol) trimethyl borate (3.75 g, 4.12 ml, 0.036 mol) The experimental procedure was as described for the preparation of compound 2 to give a cream, waxy solid. Yield: 5.56 g (98%) 3-Fluoro-4'-octyloxybiphenyl-4-ylboronic acid (76) Quantities: 3-fluoro-4'-octyloxybiphenyl (73) (4.50 g, 0.015 mol) sec-butyllithium (13.10 ml; 1.3 mol dm _ 3 in cyclohexane, 0.017 mol) trimethyl borate (3.12 g, 3.43 ml, 0.030 mol) The experimental procedure was as described for the preparation of compound 2 to give a white solid. Yield: 5.16 g (100%) 2, 3-Difluoro-4 -pentylbiphenyl (77) Quantities: 2,3-difluorophenylboronic acid (2) (11.06 g, 0.070 mol) 1-bromo-4-pentylbenzene (38) (13.17 g, 0.058 mol) tetrakis(triphenylphosphine)palladium(0) (3.35 g, 2.90 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless liquid which was further purified by Kugelrohr distillation (100 °C at 0.2 mmHg) to give a colourless oil. Yield: 11.44 g (76%) 1 H NMR (CDCI3) d: 0.91 (3H, t), 1.28-1.43(4H, m), 1.65(2H, quint), 2.65(2H, t), 7.05-7.22(3H, m), 7.27(2H, d), 7.45(2H, d). MS (m/z): 260(M + ), 203(100%). 2, 3-Difluoro-4 '-heptylbiphenyl (78) Quantities: 2,3-difluorophenylboronic acid (2) (9.86 g, 0.062 mol) 1-bromo-4-heptylbenzene (39) (13.28 g, 0.052 mol) tetrakis(triphenylphosphine)palladium(0) (3.01 g, 2.60 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless liquid which was further purified by Kugelrohr distillation (175 °C at 0.3 mmHg) to give a colourless oil. Yield: 12.03 g (80%) 1 H NMR (CDCI3) d: 0.89(3H, t), 1.20-1.43(8H, m), 1.65(2H, quint), 2.65(2H, t), 7.04-7.22(3H, m), 7.26(2H, d), 7.45(2H, d). MS (m/z) 288(M + ), 203(100%). 2, 3-Difluoro-4 '-nonylbiphenyl (79) Quantities: 2,3-difluorophenylboronic acid (2) (8.85 g, 0.056 mol) 1-bromo-4-nonylbenzene (40) (13.30 g, 0.047 mol) tetrakis(triphenylphosphine)palladium(0) (2.72 g, 2.35 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless liquid which was further purified by Kugelrohr distillation (150 °C at 0.15 mmHg) to give a colourless oil. Yield: 13.06 g (88%) 1 H NMR (CDCI3) d: 0.88(3H, t), 1.20-1.43(12H, m), 1.65(2H, quint), 2.65(2H, t), 7.06-7.22(3H, m), 7.26(2H, d), 7.45(2H, d). MS (m/z): 316(M + ), 203(100%). 2,3-Difluoro-4'-pentylbiphenyl-4-ylboronic acid (80) Quantities: 2,3-difluoro-4'-pentylbiphenyl (77) (5.55 g, 0.021 mol) π-butyllithium (9.20 ml, 0.023 mol) trimethyl borate (4.37 g, 3.98 ml, 0.042 mol) The experimental procedure was as described for the preparation of compound 2 to give a cream, crystalline solid. Yield: 6.35 g (99%) 2,3-Difluoro-4'-heptylbiphenyl-4-ylboronic acid (81) Quantities: 2,3-difluoro-4'-heptylbiphenyl (78) (11.86 g, 0.041 mol) π-butyllithium (18.12 ml, 0.045 mol) trimethyl borate (8.53 g, 9.37 ml, 0.082 mol) The experimental procedure was as described for the preparation of compound 2 to give a white solid. Yield: 13.57 g (100%) 2,3-Difluoro-4'-nonylbiphenyl-4-ylboronic acid (82) Quantities: 2,3-difluoro-4'-nonylbiphenyl (79) (12.76 g, 0.040 mol) π-butyllithium (17.76 ml, 0.045 mol) trimethyl borate (8.32 g, 9.14 ml, 0.080 mol) The experimental procedure was as described for the preparation of compound 2 to give a white solid. Yield: 14.42 g (100%) 4 '-Bromo-2, 3-difluoro-4-hexyloxybiphenyl (83) Quantities: 2,3-difluoro-4-hexyloxyphenylboronic acid (11) (6.31 g, 0.024 mol) 1-bromo-4-iodobenzene (65) (4.53 g, 0.016 mol) tetrakis(triphenylphosphine)palladium(0) (0.93 g, 0.80 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to yield a colourless crystalline solid. Yield: 3.22 g (55%) mp: 48-51 °C 1 H NMR (CDCI3) d: 0.91 (3H, t), 1.25-1.55(6H, m), 1.84(2H, quint), 4.07(2H, t), 6.79(1 H, ddd), 7.05(1 H, ddd), 7.36(2H, d), 7.56(2H, d). IR (KBr) v ma χ/cm- 1 : 1310. MS (m/z) 370(M + ), 368(M + ), 284(100%). 4'-Bromo-4-butyloxy-2,2', 3-trifluorobiphenyl (85) Quantities: 4-butyloxy-2,3-difluorophenylboronic acid (10) (7.13 g, 0.031 mol) 4-bromo-2-fluoro-1-iodobenzene (61) (8.43 g, 0.028 mol) tetrakis(triphenylphosphine)palladium(0) (1.62 g, 1.40 mmol) The experimental procedure was as described for the preparation of compound 66, however, the resulting mixture was maintained under gentle heat and not allowed to come to reflux. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless oil which was further purified by Kugelrohr distillation (175 °C at 0.25 mmHg) to yield a colourless crystalline solid. Yield: 4.64 g (46%) mp: 52-55 °C 1 H NMR (CDCI3) d: 0.99(3H, t), 1.52(2H, sext), 1.83(2H, quint), 4.09(2H, t), 6.80(1 H, ddd), 7.00(1 H, ddd), 7.22(1 H, dd), 7.30-7.39(2H, m). MS (m/z): 360(M + ), 358(M + ), 302(100%). 4'-Bromo-2,2',3-trifluoro-4-hexyloxybiphenyl (86) Quantities: 2,3-difluoro-4-hexyloxyphenylboronic acid (11) (4.85 g, 0.019 mol) 4-bromo-2-fluoro-1-iodobenzene (61 ) (5.12 g, 0.017 mol) tetrakis(triphenylphosphine)palladium(0) (0.98 g, 0.85 mmol) The experimental procedure was as described for the preparation of compound 66, however, the resulting mixture was maintained under gentle heat and not allowed to come to reflux. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless oil which was further purified by Kugelrohr distillation (125 °C at 0.1 mmHg) to give a colourless oil. Yield: 3.20 g (49%) 1 H NMR (CDCI3) d: 0.90(3H, t), 1.20-1.55(6H, m), 1.85(2H, quint), 4.05(2H, t), 6.79(1 H, ddd), 7.00(1 H, ddd), 7.22(1 H, dd), 7.29-7.39(2H, m). MS (m/z) 388(M + ), 386(M + , 100%). 4 '-Bromo-2, 2 ', 3-trifluoro-4-octyloxybiphenyl (87) Quantities: 2,3-difluoro-4-octyloxyphenylboronic acid (12) (3.03 g, 0.011 mol) 4-bromo-2-fluoro-1-iodobenzene (61) (2.90 g, 9.64 mmol) tetrakis(triphenylphosphine)palladium(0) (0.56 g, 0.482 mmol) The experimental procedure was as described for the preparation of compound 66, however, the resulting mixture was maintained under gentle heat and not allowed to come to reflux. The crude product was purified by gravity column chromatography (silica gel; petrol/dichloromethane, 9:1) to give a colourless liquid which was further purified by Kugelrohr distillation (150 °C at 0.2 mmHg) to yield a colourless solid on cooling. Yield: 2.42 g (60%) mp: 42-43.5 °C 1 H NMR (CDCI3) d: 0.88(3H, t), 1.20-1.55(10H, m), 1.85(2H, quint), 4.07(2H, t), 6.79(1 H, ddd), 7.01(1 H, ddd), 7.23(1H, dd), 7.31-7.39(2H, m). MS (m/z): 416(M + ), 414(M + ), 302(100%). 4 '-Bromo-4-decyloxy-2,2', 3-trifluorobiphenyl (88) Quantities: 4-decyloxy-2,3-difluorophenylboronic acid (13) (6.91 g, 0.022 mol) 4-bromo-2-fluoro-1-iodobenzene (61) (6.00 g, 0.020 mol) tetrakis(t phenylphosphine)palladium(0) (1.16 g, 1.00 mmol) The experimental procedure was as described for the preparation of compound 66, however, the resulting mixture was maintained under gentle heat and not allowed to come to reflux. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless, soft waxy solid which was further purified by Kugelrohr distillation (220 °C at 0.2 mmHg) to give a colourless crystalline solid. Yield: 5.67 g (64%) purity 90% by GLC mp: 36-38 °C 1 H NMR (CDCI3) d: 0.88(3H, t), 1.20-1.55(14H, m), 1.84(2H, quint), 4.07(2H, t), 6.79(1 H, ddd), 7.00(1 H, ddd), 7.22(1 H, dd), 7.30-7.39(2H, m). MS (m/z): 444(M + ), 442(M + ), 302(100%). 4'-Bromo-2,2',3-trifluoro-4-pentylbiphenyl (89) Quantities: 2,3-difluoro-4-pentylphenylboronic acid (24) (10.53 g, 0.046 mol) 4-bromo-2-fluoro-1-iodobenzene (61) (12.65 g, 0.042 mol) tetrakis(triphenylphosphine)palladium(0) (2.43 g, 2.10 mmol) The experimental procedure was as described for the preparation of compound 66, however, the resulting mixture was maintained under gentle heat and not allowed to come to reflux. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless liquid which was further purified by Kugelrohr distillation (160 °C at 0.1 mmHg) to give a colourless oil. Yield: 8.72 g (58%) H NMR (CDCI3) d: 0.91 (3H, t), 1.28-1.45(4H, m), 1.65(2H, quint), 2.69(2H, t), 6.95-7.05(2H, m), 7.25(1 H, dd), 7.32-7.40(2H, m). MS (m/z): 358(M + ), 356(M + ), 301 (100%), 219(100%). 4'-Bromo-2,2', 3-t fluoro-4-heptylbiphenyl (90) Quantities: 2,3-difluoro-4-heptylphenylboronic acid (25) (11.01 g, 0.043 mol) 4-bromo-2-fluoro-1-iodobenzene (61) (11.74 g, 0.039 mol) tetrakis(triphenylphosphine)palladium(0) (2.25 g, 1.95 mmol) The experimental procedure was as described for the preparation of compound 66, however, the resulting mixture was maintained under gentle heat and not allowed to come to reflux. The crude product was purified by gravity column chromatography (silica gel; hexane) to give a colourless liquid which was further purified by Kugelrohr distillation (160 °C at 0.15 mmHg) to give a colourless oil. Yield: 6.97 g (46%) H NMR (CDCI3) d: 0.89(3H, t), 1.20-1.44(8H, m), 1.64(2H, quint), 2.69(2H, t), 6.95-7.05(2H, m), 7.25(1 H, dd), 7.32-7.40(2H, m). MS (m/z): 386(M + ), 384(M + ), 299(100%). 4'-Bromo-2,2', 3-trifluoro-4-nonylbiphenyl (91 ) Quantities: 2,3-difluoro-4-nonylphenylboronic acid (26) (11.36 g, 0.040 mol) 4-bromo-2-fluoro-1-iodobenzene (61) (10.93 g, 0.036 mol) tetrakis(triphenylphosphine)palladium(0) (2.08 g, 1.83 mmol) The experimental procedure was as described for the preparation of compound 66, however, the resulting mixture was maintained under gentle heat and not allowed to come to reflux. The crude product was purified by gravity column chromatography (silica gel; hexane) to give a colourless liquid which was further purified by Kugelrohr distillation (175 °C at 0.15 mmHg) to give a colourless oil. Yield: 6.22 g (31%) 1 H NMR (CDCI3) d: 0.88(3H, t), 1.18-1.44(12H, m), 1.64(2H, quint), 2.69(2H, t), 6.95-7.05(2H, m), 7.24(1 H, dd), 7.32-7.39(2H, m). MS (m/z): 414(M + ), 412(M + ), 57(100%). 4-Decyloxy-2,2',3-trifluoro-4'-nonylbiphenyl (92) Quantities: 4-decyloxy-2,3-difluorophenylboronic acid (13) (0.86 g, 2.75 mmol) 1-bromo-2-fluoro-4-nonylbenzene (60) (0.72 g, 2.39 mmol) tetrakis(triphenylphosphine)palladium(0) (0.14 g, 0.12 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; hexane) to give a colourless solid. The product was recrystallised from ethanol/ethyl acetate (5:1) to yield colourless crystals. Yield: 0.89 g (76%) mp: 33-36 °C 1 H NMR (CDC*3) d: 0.88(6H, 2 x t), 1.19-1.56(26H, m), 1.64(2H, quint), 1.84(2H, quint), 2.63(2H, t), 4.07(2H, t), 6.78(1 H, ddd), 6.93-7.08(3H, m), 7.24(1 H, dd). MS (m/z): 490(M + ), 237(100%). 4-Butyloxy-2, 2 ', 3-t fluoro-4 "-nonylterphenyl (94) Quantities: 4-nonylphenylboronic acid (44) (1.85 g, 7.46 mmol) 4'-bromo-4-butyloxy-2,2',3-trifluorobiphenyl (85) (2.23 g, 6.22 mmol) tetrakis(triphenylphosphine)palladium(0) (0.36 g, 0.31 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (9:1) to yield colourless crystals. Yield: 2.33 g (78%) Transitions (°C): Cryst 57.7 Sc 87.0 SA 89.1 N 112.9 Iso H NMR (CDCI3) d: 0.88(3H, t), 1.00(3H, t), 1.20-1.44(12H, m), 1.45-1.72(4H, m), 1.84(2H, quint), 2.65(2H, t), 4.10(2H, t), 6.81 (1 H, ddd), 7.08(1 H, ddd), 7.27(2H, d), 7.34-7.46(3H, m), 7.53(2H, d). MS (m/z): 482(M + ), 43(100%). 2, 2 ', 3- Trifluoro-4 "-heptyl-4-hexyloxyterphenyl (95) Quantities: 4-heptylphenylboronic acid (43) (1.09 g, 4.96 mmol) 4'-bromo-2,2',3-trifluoro-4-hexyloxybiphenyl (86) (1.60 g, 4.13 mmol) tetrakis(thphenylphosphine)palladium(0) (0.24 g, 0.207 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (3:1) to yield colourless crystals. Yield: 1.19 g (60%) Transitions (°C): Cryst 40.1 Sc 75.7 N 111.8 Iso H NMR (CDCI3) d: 0.89(3H, t), 0.92(3H, t), 1.20-1.56(141-1, m), 1.65(21-1, quint), 1.85(2H, quint), 2.65(2H, t), 4.08(2H, t), 6.81 (1 H, ddd), 7.08(1 H, ddd), 7.27(2H, d), 7.34-7.46(3H, m), 7.53(2H, d). IR vmax/cm "1 : 1300. MS (m/z): 482(M + ), 43(100%). 2,2',3-Trifluoro-4-hexyloxy-4"-nonylterphenyl (96) Quantities: 4-nonylphenylboronic acid (44) (1.16 g, 4.66 mmol) 4'-bromo-2,2',3-trifluoro-4-hexyloxybiphenyl (86) (1.50 g, 3.88 mmol) tetrakis(triphenylphosphine)palladium(0) (0.22 g, 0.194 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol/ dichloromethane, 9:1) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (2:1) to yield colourless crystals. Yield: 1.38 g (70%) Transitions (°C): Cryst 47.9 Sc 91.5 N 109.6 Iso H NMR (CDCI3) d: 0.88(3H, t), 0.92(3H, t), 1.20-1.56(18H, m), 1.65(21-1, quint), 1.85(21-1, quint), 2.65(2H, t), 4.09(2H, t), 6.81 (1 H, ddd), 7.08(1 H, ddd), 7.27(2H, d), 7.34-7.46(3H, m), 7.53(2H, d). IR max/cm" 1 : 1295. MS (m/z): 510(M + ), 43(100%). 2,2',3-T fluoro-4-hexyloxy-4"-undecylterphenyl (97) Quantities: 4-undecylphenylboronic acid (45) (1.37 g, 4.96 mmol) 4'-bromo-2,2',3-trifluoro-4-hexyloxybiphenyl (86) (1.60 g, 4.13 mmol) tetrakis(triphenylphosphine)palladium(0) (0.23 g, 0.21 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; hexane-ethyl acetate, 9:1) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (3:1) to yield colourless crystals. Yield: 0.87 g (39%) Transitions (°C): Cryst 51.2 Sc 95.2 SA 98.6 N 106.2 Iso H NMR (CDCI3) d: 0.88(3H, t), 0.92(3H, t), 1.19-1.43(20H, m), 1.49(2H, quint), 1.65(2H, quint), 1.85(2H, quint), 2.65(2H, t), 4.09(2H, t), 6.81 (1 H, ddd), 7.08(1 H, ddd), 7.27(2H, d), 7.34-7.46(3H, m), 7.53(2H, d). MS (m/z): 538(M + ), 43(100%). 2,2',3-Trifluoro-4-octyloxy-4"-pentylterphenyl (98) Quantities: 4-pentylphenylboronic acid (42) (0.69 g, 4.85 mmol) 4'-bromo-2,2',3-thfluoro-4-octyloxybiphenyl (87) (1.25 g, 3.01 mmol) tetrakis(thphenylphosphine)palladium(0) (0.17 g, 0.151 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol/ dichloromethane, 4:1) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (2:1) to yield colourless crystals. Yield: 0.74 g (51 %) Transitions (°C): Cryst 47.3 Sc 50.2 N 110.3 Iso 1 H NMR (CDCI3) d: 0.89(3H, t), 0.92(3H, t), 1.20-1.56(14H, m), 1.66(2H, quint), 1.85(2H, quint), 2.66(2H, t), 4.09(2H, t), 6.81 (1 H, ddd), 7.08(1 H, ddd), 7.27(2H, d), 7.34-7.47(3H, m), 7.53(2H, d). IR (KBr) v ma χ/crrr 1 : 1295. MS (m/z): 482(M + ), 313(100%). 2,2',3-Trifluoro-4"-nonyl-4-octyloxyterphenyl (99) Quantities: 4-nonylphenylboronic acid (44) (1.66 g, 6.70 mmol) 4'-bromo-2,2',3-thfluoro-4-octyloxybiphenyl (87) (2.31 g, 5.58 mmol) tetrakis(triphenylphosphine)palladium(0) (0.32 g, 0.279 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (2:1) to yield colourless crystals. Yield: 2.18 g (73%) Transitions (°C): Cryst 55.4 Sc 95.0 N 107.3 Iso H NMR (CDCI3) d: 0.88(3H, t), 0.90(3H, t), 1.20-1.55(22H, m), 1.65(2H, quint), 1.85(2H, quint), 2.65(2H, t), 4.09(2H, t), 6.81(1 H, ddd), 7.08(1 H, ddd), 7.27(2H, d), 7.34-7.47(3H, m), 7.53(2H, d). MS (m/z): 538(M + ), 313(100%). 4-Decyloxy-2,2', 3-trifluoro-4"-pentylterphenyl (100) Quantities: 4-pentylphenylboronic acid (42) (0.77 g, 4.00 mmol) 4'-bromo-4-decyloxy-2,2',3-trifluorobiphenyl (88) (purity 90%, 1.48 g, 3.01 mmol) tetrakis(triphenylphosphine)palladium(0) (0.19 g, 0.167 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (19:1) to yield colourless crystals. Yield: 1.28 g (83%) Transitions (°C): Cryst 56.1 (Sc 52.1) N 102.1 Iso 1 H NMR (CDC*3) d: 0.89(3H, t), 0.91 (3H, t), 1.19-1.55(18H, m), 1.66(2H, quint), 1.85(2H, quint), 2.65(2H, t), 4.09(2H, t), 6.81 (1 H, ddd), 7.08(1 H, ddd), 7.27(2H, d), 7.34-7.47(3H, m), 7.53(2H, d). MS (m/z) 510(M + ), 57(100%). 4-Decyloxy-2,2', 3-trifluoro-4 "-heptylterphenyl (101 ) Quantities: 4-heptylphenylboronic acid (43) (0.85 g, 4.02 mmol) 4'-bromo-4-decyloxy-2,2',3-trifluorobiphenyl (88) (purity 90%, 1.48 g, 3.01 mmol) tetrakis(t phenylphosphine)palladium(0) (0.19 g, 0.168 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (19:1) to yield colourless crystals. Yield: 0.74 g (46%) Transitions (°C): Cryst 56.0 Sc 83.2 N 104.5 Iso H NMR (CDCl3) d: 0.89(6H, 2 x t), 1.20-1.56(22H, m), 1.65(2H, quint), 1.85(2H, quint), 2.65(2H, t), 4.09(2H, t), 6.81(1 H, ddd), 7.08(1 H, ddd), 7.27(2H, d), 7.33-7.47(3H, m), 7.53(2H, d). MS (m/z): 538(M + ), 55(100%). 4-Decyloxy-2, 2 ', 3-tήfluoro-4 "-nonylterphenyl (102) Quantities: 4-nonylphenylboronic acid (44) (0.95 g, 3.82 mmol) 4'-bromo-4-decyloxy-2,2',3-thfluorobiphenyl (88) (purity 90%, 1.41 g, 2.86 mmol) tetrakis(triphenylphosphine)palladium(0) (0.18 g, 0.159 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (2:1) to yield colourless crystals. Yield: 1.47 g (91%) Transitions (°C): Cryst 59.6 Sc 95.9 N 104.4 Iso 1 H NMR (CDCI3) d: 0.89(6H, 2 x t), 1.20-1.56(26H, m), 1.65(2H, quint), 1.85(2H, quint), 2.65(2H, t), 4.09(2H, t), 6.82(1 H, ddd), 7.09(1 H, ddd), 7.27(2H, d), 7.34-7.47(3H, m), 7.53(2H, d). MS (m/z): 566(M + ), 57(100%). 2, 2 ', 3- Trifluoro-4 "-heptyl-4-pentylterphenyl (103) Quantities: 4-heptylphenylboronic acid (43) (1.75 g, 7.97 mmol) 4'-bromo-2,2',3-trifluoro-4-pentylbiphenyl (89) (2.37 g, 6.64 mmol) tetrakis(triphenylphosphine)palladium(0) (0.38 g, 0.33 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; hexane) to afford a colourless liquid which was further purified by Kugelrohr distillation (175 °C at 0.15 mmHg) in order to remove unreacted or debrominated bromobiphenyl. The resultant semi-solid (smectic liquid crystal phase) was filtered through a short silica gel column eluted with hexane in order to remove colour due to charring. The solvent was removed in vacuo and the smectogen was dried in vacuo (P2O5, RT, 0.1 mmHg). Yield: 1.54 g (54%) Transitions (°C): Sc 37.2 SA 51.7 N 75.0 Iso 1 H NMR (CDCI3) d: 0.89(3H, t), 0.92(3H, t), 1.20-1.45(12H, m), 1.66(4H, 2 x quint), 2.65(2H, t), 2.71 (2H, t), 7.01 (1 H, ddd), 7.09(1 H, ddd), 7.27(2H, d), 7.34-7.47(3H, m), 7.53(2H, d). MS (m/z): 452(M + ), 367(100%), 58(100%). 2, 2 ', 3- Trifluoro-4 "-nonyl-4-pentylterphenyl ( 104) Quantities: 4-nonylphenylboronic acid (44) (1.86 g, 7.50 mmol) 4'-bromo-2,2',3-trifluoro-4-pentylbiphenyl (89) (2.23 g, 6.25 mmol) tetrakis(triphenylphosphine)palladium(0) (0.36 g, 0.31 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; hexane) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (4:1) to yield colourless crystals. Yield: 1.80 g (60%) Transitions (°C): Cryst 30.8 Sc 49.2 SA 78.6 N 83.1 Iso 1 H NMR (CDCI3) d: 0.88(3H, t), 0.92(3H, t), 1.19-1.45(16H, m), 1.65(4H, 2 x quint), 2.65(2H, t), 2.70(2H, t), 7.00(1 H, ddd), 7.09(1 H, ddd), 7.27(2H, d), 7.34-7.47(3H, m), 7.53(2H, d). MS (m/z): 480(M + ), 367(100%). 2, 2 ', 3- T fluoro-4-heptyl-4 "-nonyiterphenyl ( 105) Quantities: 4-nonylphenylboronic acid (44) (1.23 g, 4.96 mmol) 4'-bromo-2,2',3-trifluoro-4-heptylbiphenyl (90) (1.60 g, 4.16 mmol) tetrakis(triphenylphosphine)pa!ladium(0) (0.15 g, 0.13 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; hexane) to give a colourless solid which was recrystallised from ethanol to yield colourless crystals. Yield: 1.23 g (58%) Transitions (°C): Cryst 28.0 Sc 52.0 SA 78.5 N 81.0 Iso 1 H NMR (CDC*3) d: 0.89(6H, 2 x t), 1.15-1.45(20H, m), 1.65(4H, 2 x quint), 2.65(2H, t), 2.70(2H, t), 7.01 (1 H, ddd), 7.09(1 H, ddd), 7.27(2H, d), 7.34-7.49(3H, m), 7.53(2H, d). MS (m/z): 508(M + ), 395(100%). 2, 2 ', 3- Trifluoro-4, 4 "-dinonylterphenyl ( 106) Quantities: 4-nonylphenylboronic acid (44) (1.39 g, 5.59 mmol) 4'-bromo-2,2',3-trifluoro-4-nonylbiphenyl (91) (1.93 g, 4.66 mmol) tetrakis(thphenylphosphine)palladium(0) (0.27 g, 0.23 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; hexane) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (5:1) to yield colourless crystals. Yield: 1.84 g (74%) Transitions (°C): Cryst 45.6 Sc 54.7 SA 79.8 N 80.8 Iso 1 H NMR (CDCI3) d: 0.88(6H, 2 x t), 1.19-1.45(24H, m), 1.65(4H, 2 x quint), 2.65(2H, t), 2.70(2H, t), 7.00(1 H, ddd), 7.09(1 H, ddd), 7.27(2H, d), 7.35-7.48(3H, m), 7.53(2H, d). MS (m/z): 536(M + ), 424(100%). 2, 2 ', 3- Trifluoro-4-heptyl-4 "-pentylterphenyl ( 107) Quantities: 1-(4-pentylphenyl)-2,6-dioxabohnane (46) (0.83 g, 3.58 mmol) 4'-bromo-2,2',3-trifluoro-4-heptylbenzene (90) (1.15 g, 2.99 mmol) anhydrous potassium phosphate (0.95 g, 4.49 mmol) tetrakis(triphenylphosphine)palladium(0) (0.17 g, 0.15 mmol) Tetrakis(triphenylphosphine)palladium(0) was added to a mixture of anhydrous potassium phosphate, 1-(4-pentylphenyl)-2,6-dioxaborinane and 4'-bromo-2,2',3-trifluoro-4- heptylbenzene in dry DMF (100 ml) under an atmosphere of dry nitrogen. The stirred reaction mixture was heated at 90 °C overnight (GLC analysis revealed a complete reaction) and the cooled mixture was poured into water. The product was extracted into ether, the ethereal extract was washed with brine, dried (MgSO4), and the solvent was removed in vacuo. The crude product was purified by gravity column chromatography (silica gel; hexane) to afford a cloudy liquid which was further purified by Kugelrohr distillation (220 °C at 0.15 mmHg) in order to remove unreacted or debrominated bromobiphenyl. The resultant opaque liquid (nematic liquid crystal phase) was passed through a short silica gel column eluted with hexane in order to remove colour due to charring. The solvent was removed in vacuo and the nematogen dried in vacuo (P2O5, RT, 0.1 mmHg). Yield: 1.1 1 g (82%) Transitions (°C): Cryst 22.7 (Sc 8.2) N 75.5 Iso 1 H NMR (CDCI3) d: 0.89(3H, t), 0.91 (3H, t), 1.21-1.45(12H, m), 1.66(4H, 2 x quint), 2.65(2H, t), 2.70(2H, t), 7.00(1 H, ddd), 7.09(1 H, ddd), 7.27(2H, d), 7.35-7.48(3H, m), 7.53(2H, d). MS (m/z): 452(M + ), 139(100%). 2,2', 3-Trifluoro-4,4"-diheptylterphenyl (108) Quantities: 1-(4-heptylphenyl)-2,6-dioxabohnane (47) (1.30 g, 3.38 mmol) 4-bromo-2,2',3-trifluoro-4-heptylbiphenyl (90) (1.57 g, 5.21 mmol) anhydrous potassium phosphate (1.07 g, 5.07 mmol) tetrakis(triphenylphosphine)palladium(0) (0.20 g, 0.17 mmol) Tetrakis(triphenylphosphine)palladium(0) was added to a mixture of anhydrous potassium phosphate, 1-(4-heptylphenyl)-2,6-dioxaborinane and 4-bromo-2,2',3-trifluoro-4- heptylbiphenyl in dry DMF (100 ml) under an atmosphere of dry nitrogen. The stirred reaction mixture was heated at 90 °C overnight (GLC analysis revealed a complete reaction) and the cooled mixture was poured into water. The product was extracted into ether, the ethereal extract was washed with brine, dried (MgSO4), and the solvent was removed in vacuo. The crude product was purified by gravity column chromatography (silica gel; hexane) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (5:1) to yield colourless crystals. Yield: 1.01 g (62%) Transitions (°C): Cryst 38.1 Sc 50.8 SA 64.6 N 80.8 Iso H NMR (CDC*3) d: 0.89(6H, 2 x t), 1.20-1.45(16H, m), 1.65(4H, 2 x quint), 2.65(2H, t), 2.70(2H, t), 7.00(1 H, ddd), 7.09(1 H, ddd), 7.27(2H, d), 7.35-7.48(3H, m), 7.53(2H, d). MS (m/z) 480(M + ), 396(100%). 2,2',3-Trifluoro-4-nonyl-4"-pentylterphenyl (109) Quantities: 1-(4-pentylphenyl)-2,6-dioxaborinane (46) (1.15 g, 4.94 mmol) 4'-bromo-2,2',3-trifluoro-4-nonylbenzene (91) (1.70 g, 4.12 mmol) anhydrous potassium phosphate (1.31 g, 6.18 mmol) tetrakis(t phenylphosphine)palladium(0) (0.24 g, 0.21 mmol) Tetrakis(triphenylphosphine)palladium(0) was added to a mixture of anhydrous potassium phosphate, 1-(4-pentylphenyl)-2,6-dioxaborinane and 4'-bromo-2,2',3-trifiuoro-4- nonylbenzene in dry DMF (100 ml) under an atmosphere of dry nitrogen. The stirred reaction mixture was heated at 90 °C overnight (GLC analysis revealed a complete reaction) and the cooled mixture was poured into water. The product was extracted into ether, the ethereal extract was washed with brine, dried (MgSO4), and the solvent was removed in vacuo. The crude product was purified by gravity column chromatography (silica gel; hexane) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (3:1) to yield colourless crystals. Yield: 1.17 g (59%) Transitions (°C): Cryst 36.1 N 77.5 Iso 1 H NMR (CDCI3) d: 0.89(3H, t), 0.91(3H, t), 1.20-1.45(161-1, m), 1.66(4H, 2 x quint), 2.65(2H, t), 2.70(2H, t), 7.00(1 H, ddd), 7.09(1 H, ddd), 7.27(2H, d), 7.34-7.48(3H, m), 7.53(2H, d). MS (m/z): 480(M + ), 310(100%). 2, 2 ', 3- Trifluoro-4 "-heptyl-4-nonylterphenyl (110) Quantities: 1-(4-heptylphenyl)-2,6-dioxaborinane (47) (1.51 g, 5.81 mmol) 4'-broιmo-2,2',3-trifluoro-4-nonylbenzene (91) (2.00 g, 4.84 mmol) anhydrous potassium phosphate (1.54 g, 7.26 mmol) tetrakis(thphenylphosphine)palladium(0) (0.28 g, 0.24 mmol) Tetrakis(triphenylphosphine)palladium(0) was added to a mixture of anhydrous potassium phosphate, 1-(4-heptylphenyl)-2,6-dioxaborinane and 4'-bromo-2,2',3-trifluoro-4- nonylbenzene in dry DMF (100 ml) under an atmosphere of dry nitrogen. The stirred reaction mixture was heated at 90 °C overnight (GLC analysis revealed a complete reaction) and the cooled mixture was poured into water. The product was extracted into ether, the ethereal extract was washed with brine, dried (MgSO4), and the solvent was removed in vacuo. The crude product was purified by gravity column chromatography (silica gel; hexane) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (5:1) to yield colourless crystals. Yield: 1.55 g (63%) Transitions (°C): Cryst 37.0 Sc 51.3 SA 67.4 N 79.6 Iso 1 H NMR (CDCl3) d: 0.88(6H, 2 x t), 1.19-1.45(20H, m), 1.65(4H, 2 x quint), 2.65(2H, t), 2.70(2H, t), 7.00(1 H, ddd), 7.08(1 H, ddd), 7.27(2H, d), 7.34-7.48(3H, m), 7.53(2H, d). MS (m/z): 508(M + ), 310(100%). 2, 2 ', 3- Trifluoro-4-hexyloxy-4 "-pentylterphenyl (111) Quantities: 2,3-difluoro-4-hexyloxyphenylboronic acid (11) (1.17 g, 4.55 mmol) 4-bromo-3-fluoro-4'-pentylbiphenyl (68) (1.17 g, 3.64 mmol) tetrakis(triphenylphosphine)palladium(0) (0.21 g, 0.182 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless solid which was recrystallised from ethanol to yield colourless crystals. Yield: 1.22 g (74%) Transitions (°C): Cryst 43.8 (Sc 38.1) N 112.3 Iso 1 H NMR (CDCI3) d: 0.91 (3H, t), 0.92(3H, t), 1.27-1.56(10H, m), 1.66(2H, quint), 1.85(2H, quint), 2.65(2H, t), 4.09(2H, t), 6.81 (1 H, ddd), 7.08(1 H, ddd), 7.27(2H, d), 7.33-7.48(3H, m), 7.53(2H, d). MS (m/z): 454(M + ), 314(100%). 2, 2 3- Trifluoro-4-4 "-dipentylterphenyl (112) Quantities: 2,3-difluoro-4-pentylphenylboronic acid (24) (0.97 g, 4.25 mmol) 4-bromo-3-fluoro-4'-pentylbiphenyl (68) (1.14 g, 3.54 mmol) tetrakis(triphenylphosphine)palladium(0) (0.20 g, 0.177 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (5:1) to yield colourless crystals. Yield: 0.49 g (43%) Transitions (°C): Cryst 31.8 (Sc 20.3) N 81.5 Iso 1 H NMR (CDCI3) d: 0.91 (3H, t), 0.92(3H, t), 1.27-1.45(8H, m), 1.66(4H, 2 x quint), 2.66(2H, t), 2.71 (2H, t), 7.01 (1 H, ddd), 7.09(1 H, ddd), 7.28(2H, d), 7.35-7.48(3H, m), 7.53(2H, d). MS (m/z) 424(M + ), 367(100%). 2, 2 ', 3- Trifluoro-4 "-hexyloxy-4-octyloxyterphenyl (113) Quantities: 3-fluoro-4'-hexyloxybiphenyl-4-ylboronic acid (75) (2.32 g, 7.33 mmol) 1-bromo-2,3-difluoro-4-octyloxybenzene (9) (1.88 g, 5.86 mmol) tetrakis(triphenylphosphine)palladium(0) (0.34 g, 0.293 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol/ dichloromethane, 19:1) to give a colourless solid which was recrystallised from ethanol to yield colourless crystals. Yield: 0.54 g (18%) Transitions (°C): Cryst 55.5 Sc 112.6 N 138.4 Iso. H NMR (CDCI3) d: 0.89(3H, t), 0.92(3H, t), 1.20-1.60(16H, m), 1.83(4H, 2 x quint), 4.01(2H, t), 4.09(2H, t), 6.81(1 H, ddd), 6.98(2H, d), 7.08(1 H, ddd), 7.31-7.43(3H, m), 7.54(2H, d). IR (KBr) v ma χ/cm- 1 : 1285. MS (m/z) 512(M + ), 316(100%). 2, 2 ', 3- T fluoro-4-hexyloxy-4 "-octyioxyterphenyl (114) Quantities: 3-fluoro-4'-octyloxybiphenyl-4-ylboronic acid (76) (2.52 g, 7.32 mmol) 1-bromo-2,3-difluoro-4-hexyloxybenzene (8) (1.72 g, 5.86 mmol) tetrakis(triphenylphosphine)palladium(0) (0.34 g, 0.293 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol/ dichloromethane, 17:3) to give a colourless solid which was recrystallised from ethanol to yield colourless crystals. Yield: 1.51 g (50%) Transitions (°C): Cryst 52.1 Sc 124.6 N 141.6 Iso 1 H NMR (CDCI3) d: 0.89(3H, t), 0.92(3H, t), 1.22-1.56(16H, m), 1.83(4H, 2 x quint), 4.01 (2H, t), 4.09(2H, t), 6.81 (1 H, ddd), 6.98(2H, d), 7.08(1 H, ddd), 7.32-7.43(3H, m), 7.54(2H, d). IR (KBr) v ma χ/cιτf 1 : 1300. MS (m/z): 512(M + ), 55(100%). 2, 2', 3-Trifluoro-4 "-heptyl-4-octyloxyterphenyl (115) Quantities: 3-fluoro-4'-heptylbiphenyl-4-ylboronic acid (74) (2.75 g, 8.76 mmol) 1-bromo-2,3-difluoro-4-octyloxybenzene (9) (2.25 g, 7.01 mmol) tetrakis(triphenylphosphine)palladium(0) (0.41 g, 0.351 mmol) The experimental procedure was as described for the preparation of compound 66. The crude product was purified by gravity column chromatography (silica gel; petrol) to give a colourless solid which was recrystallised from ethanol/ethyl acetate (2:1) to yield colourless crystals. Yield: 0.76 g (21 %) Transitions (°C): Cryst 48.0 Sc 81.0 N 108.8 Iso H NMR (CDCI3) d: 0.90(6H, 2 x t), 1.20-1.57(18H, m), 1.65(2H, quint), 1.85(2H, quint), 2.65(2H, t), 4.09(2H, t), 6.81 (1 H, ddd), 7.08(1 H, ddd), 7.27(2H, d), 7.34-7.47(3H, m), 7.53(2H, d). MS (m/z): 510(M + ), 313(100%). Compounds of formula I may be mixed with a wide range of hosts, for examplesmectic hosts to form a useful liquid crystal composition. Such compositions can have a range of Ps values. Compounds of formula I may be mixed with one or more of the types of hosts VIII- XIII. These different types of hosts may be mixed together to which the compound of general formula I may also be added. Typical hosts include: The compounds described in PCT/GB86/00040, e.g. of formula VIII VIII where R., and R 2 are independently C 3 -C 12 alkyl or alkoxy. The fluoro-terphenyls described in EPA 84304894.3 and GBA 8725928, e.g. of formula IX IX where R^ and R 2 are independently C 3 -C 12 alkyl or alkoxy, x is 1 and F may be on any of the available substitution positions on the phenyl ring specified. The difluoro-terphenyls described in GBA 8905422.5, e.g. of formula X where R., and R 2 are independently C 3 -C 12 alkyl or alkoxy. The phenyl-pyrimidines described in WO 86/00087, e.g. of formula XI. XI including those compounds where Rj is C 3 -C 12 alkyl and R 2 is given by the general formula (CH 2 ) n -CHXCH 2 CH 3 , where n is 1 to 5 and X is CN orCI. The compounds described by R Eidenschink et al in Cyclohexanederivative mit Getilteneten Smektischen Phasen at the 16 th Freiberg Liquid Crystal Conference, Freiberg, Germany, pδ. Available from E Merck Ltd, Germany, e.g. of formula XII. XII including those compounds where Rj and R 2 are independently C r C 15 alkyl. The difluoro-phenyl pyrimidines described at the 2 nd International Symposium on Ferroelectric Liquid Crystals, Gόteborg, Sweden, June 1989 by Reiffenrath et al, e.g. of formula XIII XIII including those compounds where R-, and R 2 are independently C 3 -C 9 alkyl. Compounds of the present invention may also be mixed with the knowndifluoro-biphenyls of general formula: wherein Rj and R 2 are independently selected from C 1-12 alkyl and alkoxy. Suitable dopants which may be added to the compounds of the present invention in order to introduce chirality/optical activity are typically: Other dopants which are hereby incorporated by reference include those of PCT/GB87/00441 and PCT/GB88/01111. The liquid crystal composition may further include other additives which are known per se in the art, for example for producing improved phase transitions, birefringence, viscosity and cone angle, memory angle and layer tilt. An example of the use of a compound of Formula I in a liquid crystal composition and device embodying the present invention will now be described with reference to Figures 19a and 19b The liquid crystal device consists of two transparent plates, 3 and 4, for example made from glass. These plates are coated on their internal face with transparent conducting electrodes 6 and 7. An alignment layer is introduced onto the internal faces of the cell so that a planar orientation of the molecules making up the liquid crystalline material will be approximately parallel to the glass plates 3 and 4. This is done by coating the glass plates 3,4 complete with conducting electrodes so that the intersections between each column and row forman x, y matrix of addressable elements or pixels. For some types of display the alignment directions are orthogonal. Prior to the construction of the cell the alignment layers are rubbed with a roller covered in cloth (for example made from velvet) in a given direction, the rubbing directions being arranged parallel (same or opposite direction) upon construction of the cell. A spacer 5 e.g. of polymethyl methacrylate separates the glass plates 3 and 4 to a suitable distance e.g. 2 microns. Liquid crystal material 2 is introduced between glass plates 3,4 by filling the space in between them. This may be done by flow filling the cell using standard techniques. The spacer 5 is sealed with an adhesive in a vacuum using an existing technique. Polarisers 13 may be arranged in front of and behind the cell. Alignment layers may be introduced onto one or more of the cell walls by one or more of the standard surface treatment techniques such as rubbing, oblique evaporation or as described above by the use of polymer aligning layers. In alternative embodiments the substrates with the aligning layers on them are heated and sheared to induce alignment, alternatively the substrates with the aligning layers are thermally annealed above the glass transition temperature and below the liquid crystal to isotropic phase transition in combination with an applied field. Further embodiments may involve a combination of these aligning techniques. With some of these combinations an alignment layer may not be necessary. The device may operate in a transmissive or reflective mode. In the former, light passing through the device, e.g. from a tungsten bulb, is selectively transmitted or blocked to form the desired display. In the reflective mode a mirror, or diffuse reflector, (16) is placed behind the second polariser 13 to reflect ambient light back through the cell and twopolarisers. By making the mirror partly reflecting the device may be operated both in atransmissive and reflective mode. The alignment layers have two functions, one to align contacting liquid crystal molecules in a preferred direction and the other to give a tilt to these molecules - a so called surface tilt - of a few degrees typically around 4° or 5°. The alignment layers may be formed by placing a few drops of the polyimide on to the cell wall and spinning the wall until a uniform thickness is obtained. The polyimide is then cured by heating to a predetermined temperature for a predetermined time followed by unidirectional rubbing with a roller coated with a nylon cloth. In an alternative embodiment a single polariser and dye material may be combined. It is believed that the compounds of the present invention are of particular use inferroelectric liquid crystal (FLC) devices in that they possess high lateral dipoles which in turn give rise to a high dielectric biaxiality. in achieving this, liquid crystal phase stability and in particularS c phase stability have not been unduly affected and in general low melting points have been achieved.. A high dielectric biaxiality has the advantageous effect of moving theτmin/Vmin curve closer to the origin i.e. the response time is faster and the switching voltage is decreased. Slaney et al in IDW '97, Proceedings of the Fourth International Display Workshop, pp885-886 assess liquid crystal materials forτVmin mode FLC devices. In this paper the authors discuss the various properties which are desirable forτ-Vmin mode FLC devices. The paper discusses the suitability of a number of compounds for use inτ-Vmin mode by mixing with mixture LB7. Compound 103 (23wt%) in LB7 referred to as AJS413 gives the following transitions: I 94.9-92.4 N* 76.7 S A 61.6 S c * (C1 ). Compound 101 (23wt%) in LB7 referred to as AJS415 gives the following transitions: I 100.3-97.6 N* 81.2 S A 78.5 S c * (C1 ). M v for compound 103 = -4.93 M v for compound 101 = -3.27 wherein M v is the figure of merit and the change inM v is relative to LB7. The trifluoro terphenyls of the present invention are also able to mix with one another. For example a mixture of Compound 104 (46wt%) and Compound 105 (54wt%) has the following phase transitions: I 78.6 N 75.6 S A 47.9 S c -30 K the mixture is referred to as AJS355. Figure 20 shows the relevant binary phase diagram. Compound 111 possesses a dipole moment (μ) of 4.83D. Other criteria on which the materials of the present invention may be based include one or more of the following: Spontaneous polarisation (Ps), V mιn , τ mιn , M t , M 0 , cone angle (θ), viscosity (η), memory angle (ΘJ

Claims: Claims 1. A liquid crystal material having Formula I Formula I wherein R and R' are independently selected from C 1-12 alkyl and alkoxy. 2. A liquid crystal material according to claim 1 wherein R and R' are selected from the following pairs: R = C 4 H 9 O, R'=C 9 H 19 R = C 6 H 13 O, R'=C 7 H 15 R = C 6 H 13 O, R'=C 9 H 19 R = C 6 H 13 O, R'=C 11 H 23 R = C 8 H 17 O, R-CsH-n R = C 10 H 21 O, R = C 5 H-| 1 R = C 10 H 21 O, R'=C 7 H 15 R = C 10 H 1 O, R'=C 9 H 19 R = CsHn, R' = C 7 H 15 R = C 7 H 15 , R' = C 9 H 19 R = C 9 H 19 , R' = C 9 H 19 R = C 7 H 15 , R' = C 7 H 15 R = C 9 H 19 , R' = CsHn R = C 9 H 19 , R' = C 7 H 15 R = C 6 H 13 0, R' = C 5 H H R = C 5 H U , R' = CsH^ R = C 8 H 17 O, R' = C 6 H 13 O R = C 6 H 13 O, R' = C 8 H 17 O R = C 8 H 17 O, R' = C 7 H 15 3. A liquid crystal mixture comprising at least one compound of claim 1 or 2. 4. A liquid crystal device comprising a layer of liquid crystal material contained between two spaced cell walls each bearing electrode structures and surface treated on facing surfaces to align liquid crystal material molecules, characterised in that the liquid crystal material includes a mixture as described in claim 3.

Inventors: GLENDENNING MARGARET EVELYN, GOODBY JOHN WILLIAM, GOUGH NEIL, HIRD MICHAEL, JONES JOHN CLIFFORD, LEWIS ROBERT ANDREW, SLANEY ANDREW JOHN, TOYNE KENNETH JOHNSON, GLENDENNING, MARGARET, EVELYN, GOODBY, JOHN, WILLIAM, GOUGH, NEIL, HIRD, MICHAEL, JONES, JOHN, CLIFFORD, LEWIS, ROBERT, ANDREW, SLANEY, ANDREW, JOHN, TOYNE, KENNETH, JOHNSON
Applicants: GLENDENNING MARGARET EVELYN, GOODBY JOHN WILLIAM, GOUGH NEIL, HIRD MICHAEL, JONES JOHN CLIFFORD, LEWIS ROBERT ANDREW, SECR DEFENCE, SLANEY ANDREW JOHN, TOYNE KENNETH JOHNSON, GLENDENNING, MARGARET, EVELYN, GOODBY, JOHN, WILLIAM, GOUGH, NEIL, HIRD, MICHAEL, JONES, JOHN, CLIFFORD, LEWIS, ROBERT, ANDREW, SLANEY, ANDREW, JOHN, THE SECRETARY OF STATE FOR DEFENCE, TOYNE, KENNETH, JOHNSON
Application year: 1999
Main classification: C09K19
IPC codes: C07C17, C07C45, C09K19, G02F1