bluuebunny/crossref_metadata_2025 huggingface dataset:
Dimethyl Cubane-1,4-dicarboxylate: A Practical Laboratory Scale Synthesis
Authors: Bliese Marianne , Tsanaktsidis John
Published: August 2004

Complete experimental details for the preparation of dimethyl
cubane-1,4-dicarboxylate (1) in multigram quantities, from cyclopentanone (2),
in an overall yield of c. 23% are presented.
Compounds of Copper(II) and Nickel(II) with 6,8,8,13,13,15-Hexamethyl-1,2,4,5,9,12- hexaazacyclopentadeca-5,15(1)-diene and Some 3-Substituted Homologues
Authors: Curtis Neil F. , Gladkikh Olga P. , Weatherburn David C. , De Courcey John S. , Waters T. Neil M.
Published: August 2004

Copper(II) and nickel(II) compounds, [M(L)]2+, of the macrocyclic ligand 6,8,8,13,13,15-hexamethyl-1,2,4,5,9,12-hexaazacyclopentadeca-5,15(1)-diene are formed by reaction of compounds of 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dihydrazone with methanal. Analogous reactions with aldehydes RHCO, or ketones RR′CO, form compounds of 3-R or 3-RR′ substituted ligands, [M(r- L)]2+ or [M(rr′-L)]2+, respectively. The nickel(II) cations form singlet ground state salts, e.g. [Ni(L)]X2, X = [ClO4]- or ½[ZnCl4]2-, and also triplet ground state compounds, e.g. [Ni(L) (NCS)2] and [Ni(L)(X)] (ClO4) (X = NO2-, C2O42-, N3-, etc.). The structures of [Cu(L)] (ClO4)2, [Ni(L)] (ClO4)2, the 3-propyl compound formed from butanal, [Cu(pr-L)] (ClO4)2.H2O, and the compounds of 9,11,11,16,16,18-hexamethyl-7,8,12,15,19,20-hexaazaspiro[5.14]eicosa-8,18(1)-diene (chex-L), formed from cyclohexanone, namely [Cu(chex-L)] (ClO4)2.MeOH, [Ni(chex-L)] (ClO4)2, and [Ni(chex-L)] (ClO4)2.MeOH, were determined. All have the metal ions in tetrahedrally twisted square-planar coordination, by N1, N5, N9 and N12 , with N9N12-rac, for the (L) and (pr-L) compounds, or by the structurally equivalent N3, N7, N10 and N14, with N7N10-rac, for the (chex-L) compounds. The [Cu(L)]2+ and [Cu(pr-L)]2+cations have saddle-like macrocycle conformations, with approximate mirror symmetry, while the other compounds have ′twisted′ macrocycle conformations with approximate twofold symmetry {[Cu(L)] (ClO4)2, C15H32Cl2CuN6O8, orthorhombic,P 212121, a 8·562(7), b 13·096(8), c 20·257(6) Å, Z 4, R 0·041 for 1540 reflections; [Ni(L)] (ClO4)2, C15H32Cl2N6NiO8, orthorhombic, P21/n, a 13·500(3), b 9·207(2), c 19·478(5) Å, β 103·94(2)°, Z 4, R1 0·055 for 2650 reflections; [Cu(Pr-L)] (ClO4)2.H2O, C18H40Cl2CuN6O9, monoclinic, C 2, a 24·229(5), b 13·780(3), c 8·877(2) Å, β 108·79(3)°, Z 4, R1 0·067 for 1765 reflections; [Cu(chex-L)] (ClO4)2.MeOH, C21H44Cl2CuN6O9, monoclinic, C 2/c, a 17·086(5), b 24·539(2), c 14·496(1) Å, β 89·94(2), Z 8, R1 0·072 for 2521 reflections; [Ni(chex-L)] (ClO4)2, C20H40Cl2N6NiO8, monoclinic, P 21/c, a 14·820(2), b 18·599(4), c 10·282(1) Å, β 106·26(1)°, Z 4, R1 0·067 for 2552 reflections; [Ni(chex-L)] (ClO4)2.MeOH, C21H44Cl2CuN6O9, monoclinic, C 2/c, a 14·451(2), b 24·11(2), c 16·740(3) Å, β 90·14(1)°, Z 8, R1 0·064 for 2598 reflections}.
Imidazo[1,2-b]pyridazines. XXIV Syntheses of Some 3-(Variously Substituted) Imidazo[1,2-b] pyridazines, 6-Substituted 2-Benzoyl- imidazo[1,2-b]pyridazines and Pyrimido[1,2-b]pyridazin- 5-ium-3-olates and their Interaction with Central and Mitochondrial Benzodiazepine Receptors
Authors: Schmitt Martine , Bourguignon Jean-Jacques , Barlin Gordon B. , Davies Les P.
Published: August 2004

The syntheses of some ethyl 2-{2′-aryl-6′-(chloro, iodo and
methoxy)imidazo[1,2-b]pyridazin-3′-yl}-2-(acetoxy,
acylamino, hydroxy and methoxy)acetates,
6-methyl-2-(p-tolyl)- and
6-chloro-2-(4′-chlorophenyl)-3-trimethylammoniomethylimidazo[1,2-b]pyridazine
iodides (and reactions thereof), 2-benzoyl 6-substituted
imidazo[1,2-b]pyridazines and 7-(methoxy,
chloro and
phenylthio)-2-phenylpyrimido-[1,2-b]pyridazin-5-ium-3-olates
are reported. The ability of these compounds to displace
[3H]diazepam from rat forebrain membrane
[central benzodiazepine receptor (BZR)] and rat kidney membrane
[mitochondrial (peripheral-type) benzodiazepine receptor (PBR)] has
been examined. The most active compound was ethyl
2-{6′-chloro-2′-(p-tolyl)imidazo[1,2-b]pyridazin-3′-yl}-2-hydroxyacetate
with IC50 24 nM for displacement from the BZR and
91% displacement at 1000 nM from the PBR; the most selective for the
PBR was
6-methyl-3-methylsulfonylmethyl-2-(p-tolyl)imidazo[1,2-b]pyridazine
(PBR, IC50 92 nM; BZR, 15% inhibition of binding
by [3H]diazepam at 1000 nM).
Reactions of Amino-Substituted Cyclodextrins with 2-Arylpropanoic Acid Derivatives
Authors: Easton Christopher J. , Lincoln Stephen F. , May Bruce L. , Papageorgiou John
Published: August 2004

Reactions of
6A-amino-6A-deoxy-β-cyclodextrin
and
3A-amino-3A-deoxy-(2AS,3AS)-β-cyclodextrin
with the 3-nitrophenyl esters of 2-phenylpropanoic acid and Ibuprofen occur
with only low diastereoselectivity, to afford the corresponding
arylpropanamido-substituted cyclodextrins. These amides are also formed by
decarboxylation of corresponding malonates, again with only low
diastereoselectivity. The n.m.r. spectra of the amido-substituted
cyclodextrins indicate that the aryl substituent is included within the
cyclodextrin annulus at low temperature, but becomes dissociated from the
cavity as the temperature is increased.
Syntheses, Structures and Vibrational Spectra of Some Dimethyl Sulfoxide Solvates of Bismuth(III) Bromide and Iodide
Authors: Bowmaker Graham A. , Harrowfield Jack M. , Junk Peter C. , Skelton Brian W. , White Allan H.
Published: August 2004

Room-temperature single-crystal X-ray studies are recorded for some dimethyl
sulfoxide (dmso) solvates of bismuth(III) bromide and iodide. Colourless
BiBr3.3dmso is triclinic,
P-1, a
8·467(4), b 9·109(4),
c 13·901(4) Å, α 76·34(4),
β 76·95(4), γ 64·56(4)°, Z
= 2; conventional R on
|F| was 0·050 for
No 2306 independent
‘observed’ (I >
3σ(I)) reflections. The complex is mononuclear
with a quasi-octahedral fac-bismuth environment,
[(dmso-O)3BiBr3],
isomorphous with the previously determined chloride. Orange
BiI3-2dmso is triclinic,
P-1, a
12·558(2), b 8·962(2),
c 8·342(1) Å, α 61·85(1),
β 78·27(1), γ 76·89(2)°, Z
= 2 f.u., R 0·048 for
No 1953. The complex is binuclear,
a pair of iodide atoms bridging the two bismuth atoms,
[(dmso-O)2I2Bi(µ-I)2BiI2(O-dmso)2];
the two O-dmso ligands about each six-coordinate bismuth lie
trans. Red BiI3.2 ⅔ dmso is
triclinic, P-1,
a 16·435(6), b
14·926(2), c 12·396(3) Å, α
74·89(2), β 73·24(2), γ 79·18(2)°,
Z = 6, R 0·059 for
No 5858. The complex is
[Bi(O-dmso)8]
[Bi2I9], the
eight-coordinate metal environment of the cation being, unusually,
dodecahedral; in the anion a pair of quasi-octahedral six-coordinate bismuth
atoms are bridged by three iodides,
[I3Bi(µ-I)3BiI3]3-.
Bands in the far-infrared and Raman spectra due to the
v(BiX) modes are assigned and discussed in relation to
the structures of the complexes. The assignment of the
v(BiO) modes is discussed.
Synthetic, Structural and Vibrational Spectroscopic Studies in Bismuth(III) Halide/N,N′-Aromatic Bidentate Base Systems. II Bipyridinium (2,2' Bipyridine) tetraholobismuthate (III) (Halogen = Chloride or Bromide)
Authors: Bowmaker Graham A. , Harrowfield Jack M. , Lee Aaron M. , Skelton Brian W. , White Allan H.
Published: August 2004

Syntheses and room-temperature single-crystal X-ray structure determinations
are recorded for the title compounds,
[bpyH]+[(bpy)BiX4]-,
X = Cl, Br, the chloride being obtained in a second acetonitrile-
sesquisolvated form.
[bpyH]+[(bpy)BiX4]-,
X = Cl, Br, are isomorphous, monoclinic
C2/c, a
≈ 15·3, b ≈ 9·6,
c ≈ 16·8 Å, β 109°,
Z = 4, conventional R on
|F| being 0·056, 0·059 for
No 1456, 769 independent
‘observed’ (I >
3σ(I)) reflections respectively. [bpyH]
[(bpy)BiCl4].1½MeCN is monoclinic,
P21/m,
a 9·572(2), b
34·521(8) c 8·218(2) Å, β
102·13(2)°, Z = 4,
R 0·043 for
No 2635. All anionic species are
mononuclear, the bismuth being quasi-octahedral. Bands in the far-infrared and
Raman spectra due to the vibrations of the
N2BiCl4 core in
[(bpy)BiCl4]- are
assigned, and their relationship to the vibrations of
[BiCl6]3- is discussed.
Synthetic, Structural and Vibrational Spectroscopic Studies in Bismuth(III) Halide/N,N′-Aromatic Bidentate Base Systems. V Bismuth(III) Halide/N,N′-Bidentate Ligand (1 : 2) Systems
Authors: Bowmaker Graham A. , Hannaway Frances M. M. , Junk Peter C. , Lee Aaron M. , Skelton Brian W. , White Allan H.
Published: August 2004

Syntheses and room-temperature single-crystal X-ray determinations are
recorded for a number of adducts of
BiX3/N,N′-bidentate 1 :
2 stoichiometry (N,N′-bidentate =
2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen)).
BiX3/bpy (1 : 2), X = Br, I, are isomorphous,
monoclinic,
P21/c,
a ≈ 7·5, b ≈ 31,
c ≈ 10·3 Å, β ≈ 113°,
Z = 4; conventional R on
|F| were 0·058, 0·055 for
No 1744, 2068 independent
‘observed’ (I >
3σ(I)) reflections.
BiCl3/phen (1 : 2) is monoclinic,
P21/C,
a 9·675(3), b
31·845(7), c 7·756(2) Å, β
109·94(2), Z = 4, R
0·071 for No 2537, while
BiBr3/phen (1 : 2), also monoclinic,
P21/c,
has a 17·590(5), b
8·812(2), c 17·537(7) Å, β
117·58(3)°, Z = 4;
R 0·083 for
No 890.
BiX3/phen (1 : 2).S,
X/S = Br/MeCN,
I/CH2Cl2, are isomorphous,
orthorhombic, Pna21,
a ≈ 20·7, b ≈
14·2, c ≈ 8·9 Å,
Z = 4, R 0·060,
0·046 for No 1553, 2423
respectively. All complexes are mononuclear with seven-coordinate
(N2)2BiX3
bismuth environments. Bands in the far-infrared spectra due to the
v(BiX) vibrations in
[(phen)2BiCl3] and
[(bpy)2BiX3] (X =
Br, I) are assigned and discussed in relation to the structures of the
complexes.
Synthesis of α-Tocopherol Analogues
Authors: Suarna Cacang , Dean Roger T. , Southwell-Keely Peter T.
Published: August 2004

A range of a-tocopherol analogues of varying side-chain length and structure
has been prepared by the Wittig reaction of alkyltriphenylphosphonium bromides
with either 6-benzyloxy-2,5,7,8-tetramethylchroman- 2-carbaldehyde (8) or
6-acetoxy-2,5,7,8-tetramethylchroman-2-carbaldehyde (14). These analogues
include 2-hexyl-2,5,7,8-tetramethylchroman-6-ol (11),
2-heptyl-2,5,7,8-tetramethylchroman-6-ol (12) and
2,5,7,8-tetramethyl-2-(pent-1-enyl)chroman-6-ol (15). Methoxycarbonylmethyl
6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylate (2) was formed by reaction
of the triethylammonium salt of trolox (1) with methyl bromoacetate. Reaction
of methoxycarbonylmethyltriphenylphosphonium bromide (16) with (8) did not
produce the expected methyl
3-(6-benzyloxy-2,5,7,8-tetramethylchroman-2-yl)prop-2-enoate (17), but rather
4-(6-benzyloxy-2,5,7,8-tetramethylchroman-2-yl)but-3-en-2-one (22). A proposed
mechanism for this unusual reaction is discussed.
An H.P.L.C. Study of Cooperative Guest Binding by a Covalently Linked b-Cyclodextrin Dimer
Authors: Croft Anna K. , Easton Christopher J. , Lincoln Stephen F. , May Bruce L. , Papageorgiou John
Published: August 2004

The complexation of the anions of Methyl Orange (MO¯) (1) and
Indomethacin (Ind-) (2) by the β-cyclodextrin dimer
(3) has been studied by means of high-performance liquid chromatography. The
cyclodextrin annuli are shown to jointly act as a single binding site for
complexation of MO¯ (1). Thus the association constants of
(3·3±0·3) × 103 and
(220±20) × 103 dm3
mol−1 for the 1 : 1 complexes with
β-cyclodextrin and the dimer (3), respectively, indicate very strong
cooperative binding by the annuli of the linked species. By contrast, the
complexation of Ind¯ (2) by the cyclodextrin dimer (3) is characterized
by two independent binding sites. This lack of cooperative binding is
reflected in the association constant for the 1 : 1 complex in each binding
site, which at (1·3±0·1) ×
103 dm3
mol−1 is little greater than that of
(0·7±0·05) ×
103dm3
mol−1 for the complex with β-cyclodextrin.
Oxidations of 12-Deoxy-, 12-Hydroxy-, 12-Methoxy-, and 12-Hydroxy-13-methoxy-podocarpa-8,11,13-triene Derivatives
Authors: Cambie Richard C. , Costa Maria do Céu , Woodgate Paul D. , Rutledge Peter S. , Kong Ni Na , Rickard Clifford E. F. , Lu Hantao , Metzler Michael R.
Published: August 2004

Methods for the oxidation of the aryl ring of derivatives of podocarpic acid
have been examined. Oxidation of methyl
12-hydroxypodocarpa-8,11,13-trien-19-oate (2) with phenyliodonium diacetate in
various solvents gives 8β-substituted dienones. An 8β-chloro dienone
is formed during oxidation of the phenol (2) with t-butyl hypochlorite.
Oxidation of (2) with dimethyldioxiran gives mainly the 7-ketone (13) but also
affords the novel ε-lactone (26), while treatment with ruthenium
tetraoxide also affords products of benzylic oxidation. Oxidation of methyl
podocarpa-8,11,13-trien-19-oate (4) with
m-chloroperbenzoic acid affords a B-ring lactone (29)
and, unexpectedly, a 6α-chloro 7-ketone (30). The action of cerium(IV)
ammonium nitrate on (2) gives nitro derivatives rather than oxidation
products. Oxidation of methyl
12-hydroxy-13-methoxypodocarpa-8,11,13-trien-19-oate (22) with
m-chloroperbenzoic acid gives a low yield of a 7-oxo
derivative (17) while treatment with ozone gives an unusual
α,β-unsaturated γ-lactone (31), the hydroxy lactone (33), the
unsaturated keto ester (34), and the substituted furan (35). Oxidation of (22)
with Fremy"s salt gives products of ring B oxidation. The structure of
(31) has been confirmed by X-ray crystallography.
Thermal Cyclization of γ-Sulfonimidoyl Ketones to 2,3-Dihydrofurans
Authors: Pyne Stephen G. , Dong Zemin , Skelton Brian W. , White Allan H.
Published: August 2004

The thermal cyclization of racemic γ-sulfonimidoyl ketones (1) and (2)
gave the novel 2,3-dihydrofurans (3) and (4), respectively. The structure of
(3) was determined by single-crystal X-ray structural analysis
Mechanisms of Nucleophilic Attack at Carbon - Nitrogen Double Bonds: Reactions of Benzohydrazonoyl Halides with Secondary Amines in Benzene
Authors: Rowe Jeffrey E. , Lee Kam
Published: August 2004

The reactions of a series of substituted benzohydrazonoyl halides with cyclic
secondary amines in benzene as solvent are investigated. The rate equations
for these reactions were complex and the derived rate data are reported. The
element effect data showed that the fluoro compounds only reacted when a
second amine molecule was available to assist the reaction, whereas the chloro
and bromo compounds reacted by reactions which were both first order and
second order in amine
(k′′Br :
k′′Cl =
9·5 : 1 and
k′′′Br
:k′′′Cl :
k′′′F = 4·7 : 1 :
0·65). The mechanism of these reactions is discussed.
Isomalindine-16-carboxylate, a Zwitterionic Alkaloid from Ophiorrhiza cf. communis
Authors: Arbain Dayar , Byrne Lindsay T. , Farmasi Dachriyanus Jurusan , Sargent Melvyn V.
Published: August 2004

Extraction of the aerial parts of Ophiorrhiza cf.
communisLinn. (Rubiaceae) has yielded the new quaternary
zwitterionic alkaloid isomalindine-16-carboxylate (3), the structure of which
followed from its spectroscopic properties
The Stereochemistry of Organometallic Compounds. XLIV Rhodium-Catalysed Hydroformylation of Some Alkenylthio Aromatic Compounds
Authors: Campi Eva M. , Jackson W. Roy , Trnacek Andrew E.
Published: August 2004

Rhodium-catalysed reactions of o-[(allyl and
butenyl)thio] benzonitriles and benzamides with
H2/CO give quantitative yields of aldehydes whereas
the corresponding benzylamines give only polymeric material. The results are
compared with reactions of the analogous alkenylamines and alkenyloxy
compounds.
Synthesis of Some 1H-1,2,4-Triazole, 4H-1,2,4-Triazole, Thiazolo[2,3-c]-1,2,4-triazole and 5H-1,2,4-Triazolo-[3,4-b][1,3]thiazine Derivatives by Metal Compound-Mediated Oxidative Cyclization of Derivatives of 2-(Phenylmethylidene)hydrazinecarboximidothioic Acid
Authors: Ali Abdelselam S. , Wilkie John S. , Winzenberg Kevin N.
Published: August 2004

Reaction of the methyl 2-(phenylmethylidene)hydrazinecarboximidothioate
derivatives (3a–d) and (6a,b) with iron(III) chloride afforded the
5-methylsulfanyl-3-phenyl-4H-1,2,4-triazole derivatives
(4a–d) and the
5-methylsulfanyl-3-phenyl-1H-1,2,4-triazole derivatives
(7a,b). This reaction was extended to the synthesis of the
3-phenyl-5,6-dihydrothiazolo[2,3-c]-1,2,4-triazole
derivatives (10a,b) and the
3-phenyl-6,7-dihydro-5H-1,2,4-triazolo[3,4-b][1,3]thiazine
derivatives (10c,d). Reaction of
5-(3-chlorophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione
(12a) with 1,2-dibromoethane gave (10a) together with the isomeric
2-(3-chlorophenyl)-5,6-dihydrothiazolo[3,2-b][1,2,4]triazole
(13a); similarly, reaction of (12a) with 1,3-dibromopropane afforded (10c)
along with
2-(3-chlorophenyl)-6,7-dihydro-5H-[1,2,4]triazolo[5,1-b][1,3]thiazine
(13b). The use of nickel peroxide and lead tetraacetate in place of iron(III)
chloride was investigated for some of these oxidative cyclization reactions.
Systematic Structural Modification of a Pentacyclic Helical Tubuland Host Diol
Authors: Ahn, Paul D. , Bishop, Roger , Craig Donald C. , Downing Gary A. , Scudder Marcia L.
Published: August 2004

Reaction of methylmagnesium chloride and pentacyclo[7.3.0.0
2,7.0 3,11 .0
6,10 ]dodecane-8,12-dione (4) yields the
C2-symmetric diol (5) (62%)
and the unsymmetrical diol (6) (36%) whose crystal structures are
analysed in crystal engineering terms. The former isomer is the tenth member
of the helical tubuland diol family, crystallizing in space
groupP 3121 as a microporous
lattice containing empty parallel canals with 9·
9Å2cross-sectional area. Molecules of diol (6)
hydrogen bond through (-O-H)4 cycles to form layers
which stack in space group P
21/c by means of hydrocarbon
dispersion forces. Diol (7), the bis(trifluoromethyl) analogue of (5), does
not form a helical tubuland lattice. The structure of its hemihydrate also
contains (–O–H)4 cycles but here the second
diol hydroxy group hydrogen bonds to water resulting in a network structure in
space group
P-421c.
Electrochemical Studies on the Competition Between Intramolecular Electron Transfer and Intermolecular Protonation of Nitroaryl Radical Anions in the Reductions of Apical Carboxylic Acid Substituents of 2- and 3-Nitro- 9,10-dihydro-9,10-ethanoanthracene-9-carboxylic Acids
Authors: Lay Peter A. , Norris Robert K. , Witting Paul K.
Published: August 2004

The results obtained from variable scan rate cyclic voltammetry (c.v.) on
2-nitro- and 3-nitro-9,10- dihydro-9,10-ethanoanthracene-9-carboxylic acids
[(4) and (5), respectively], combined with simulations of various
c.v. responses, are consistent with reduction of a benzylic acid group being
facilitated by an intramolecular electron transfer process. This
intramolecular process involves a one-electron reduction of the nitroaromatic
group, followed by a rapid and irreversible
π*(ArNO2)•- →
π*(RCO2H)•-
intramolecular electron transfer to the carboxylic acid group at a benzylic
bridgehead position of the acids (4) and (5). The reduction potentials of the
acid groups are shifted more than 0·3 V to positive potentials at slow
scan rates (20-100 mV s-1) compared with the unnitrated
acid derivative (6). The reduction potentials and the relative peak currents
for the reductions of the nitro and acid groups for each of compounds (4) and
(5) are dependent on the concentrations of the reactants. At concentrations of
substrate >1 mM, reduction of the acid moiety is increasingly dependent on
complex intermolecular processes. These intermolecular processes compete with
intramolecular electron transfer from the nitroaryl anion to the apical acid
group at the benzylic bridgehead position. Digital simulations of the
voltammetric data were confined to substrate concentrations <1 mM, and show
that the intramolecular reductions of the apical carboxylic acid protons of
(4) and (5) are complicated by competing intermolecular electron transfer and
intermolecular self-protonations of the nitro radical anions. The value of the
intramolecular electron transfer rate constant for the
meta compound is an order of magnitude larger than that
for the para compound, which is the opposite reactivity
pattern to that generally found in the
SRN1 reactions of
m- and p-nitrobenzyl halides. This
indicates that there is likely to be an important contribution from an
intramolecular through-space electron transfer mechanism for the former
reaction
Synthesis, Structure and Reactivity of a Novel Series of Diastereomeric Dirhodium(II) Tetracarboxamidates. Catalysts for Asymmetric Diazoacetate Transformations
Authors: Roos Gregory H. P. , Raab Conrad E. , Emslie Neville D. , Doyle Michael P. , Lynch Vincent
Published: August 2004

The synthesis and structure of a set of diastereomeric dirhodium(II)
tetrakis[methyl (4S)-1-acyl-2-
oxoimidazolidine-4-carboxylate] compounds are described, including one
X-ray crystal structure. With the N-acyl moiety based on
the mandelic acid enantiomers, these represent the first examples which
incorporate an addititional stereogenic centre in proximity to the axial sites
of the dirhodium(II) face. The preliminary catalytic profiles of these
diastereomeric complexes are also reported.
Structural Systematics of Metal Acetylide Complexes. II. X-Ray Studies of Some Nickel σ-Acetylide Complexes
Authors: Whittall Ian R. , Humphrey Mark G. , Hockless David C. R.
Published: August 2004

The structures of
Ni(C≡CR)(PPh3)(η-C5H5)
(R = Ph (1),
C6H4-4-NO2
(2),
4-C6H4C6H4-4′-NO2
(3),
(E)-4-C6H4CH=CHC6H4-4′-NO2
(4),
4-C6H4C≡CC6H4-4′-NO2
(5),
4-C6H4N=CHC6H4-4′-NO2
(6)) have been determined by single-crystal X-ray diffraction studies,
refining by full-matrix least-squares analysis. For (1), crystals are
triclinic, space group
P-1, with
a 10·094(2),
b13·429(3), c
18·835(5) Å,α 103·24(2), β 91·50(2),
γ 90·10(2)°, Z 4, 5844 unique reflections
(595 parameters), converging at R 0·033 and
Rw 0·024. For (2), crystals
are orthorhombic, space group
Pna21, with
a 16·799(2), b
8·681(2), c 17·485(2) Å,
Z 4, 1774 unique reflections (325 parameters),
converging at R 0·031 and
Rw 0·029. For (3), crystals
are monoclinic, space group P
21/c, with
a 11·140(3), b
18·282(4), c 15·296(2) Å, β
105·18(2)°, Z 4, 3132 unique reflections
(397 parameters), converging at R 0·039 and
Rw 0·024. For (4), crystals
are monoclinic, space group P
21/n, with
a 12·929(7), b
16·953(8), c 15·601(7) Å, β
112·55(3), Z 4, 3023 unique reflections (397
parameters), converging at R 0·039 and
Rw 0·025. For (5), crystals
are monoclinic, space group P
21/n, with
a 12·710(5), b
16·882(3), c 15·693(4) Å, β
111·37(3)°, Z 4, 3216 unique reflections (397
parameters), converging at R 0·035 and
Rw 0·030. For (6), crystals
are monoclinic, space group P
21/n, with
a 12·594(1), b
16·936(2), c 15·611(1) Å, β
112·476(5)°, Z 4, 3564 unique reflections
(397 parameters), converging at R 0·038 and
Rw 0·041. For structurally
characterized 18-electron (cyclopentadienyl)nickel(II) acetylide complexes,
statistically insignificant decreases in the average Ni-C(1) distance and
trans influence and an increase in the average C(1)-C(2) parameter are
observed on introduction of an acceptor substituent at the alkynyl ligand.
Sigmosceptrins A - C: New Norditerpenes from a Southern Australian Marine Sponge, Sigmosceptrella sp.
Authors: Bassett, Sean , Ovenden Simon P. B. , Gable Robert W. , Capon Robert J.
Published: August 2004

A Sigmosceptrella sp. of sponge collected during
trawling operations in the Great Australian Bight, Australia, has yielded a
series of new norterpenes. These include a new bisnorditerpene,
sigmosceptrin-A (5); two new norditerpenes, sigmosceptrin-B (14) and
sigmosceptrin-C (15), isolated as their methyl esters (6) and (7)
respectively; and an ethylated artefact, sigmosceptrin-B ethyl ester (8).
Complete stereostructures were assigned to the sigmosceptrins by spectroscopic
analysis, chemical degradation, derivatization, and by a single-crystal X-ray
structural analysis. A biosynthetic pathway is proposed that requires a common
biosynthetic precursor to both the sigmosceptrins and norterpene cyclic
peroxides.
Structural Systematics of 2/4-Nitrophenoxide Complexes of Closed-Shell Metal Ions. V 2-Nitrophenoxides of Group 2
Authors: Harrowfield Jack M. , Sharma Raj Pal , Skelton Brian W. , White Allan H.
Published: August 2004

Room-temperature single-crystal X-ray studies are recorded for
2-nitrophenoxide salts of Group 2 metals, variously hydrated
M(2-np)2.xH2O,
M = Mg, Ca, Sr; the structure of the barium analogue has been
previously recorded.
Mg(2-np)2.2H2O is monoclinic,
P21/a,
a 7·377(1), b
7·518(1), c 12·877(3) Å, β
106·58(2)°, Z = 2; conventional
R on |F| 0·13
for No 508 independent
‘observed’ (I >
3σ(I)) reflections.
Ca(2-np)2.H2O is monoclinic,
C2, a 25·92(1),
b 7·176(3), c
3·660(4) Å, β 93·66(5)°, Z
= 2, R 0·061 for
No 541.
M(2-np)2.4H2O, M = Ca, Sr,
are isomorphous, monoclinic,
C2/c, a
≈ 31·3, b ≈ 8·1,
c ≈ 12·8 Å, β 103°,
Z = 8; R was 0·056,
0·055 forNo 1988, 1744
respectively. The magnesium salt is a discrete molecular array disposed about
a crystallographic inversion centre with chelating phenoxide ligands:
trans-[Mg(2-np)2(OH2)2].
The calcium monohydrate salt is a novel one-dimensional polymer with a ...
Ca(µ-O)2Ca(µ-O)2Ca ...
spine, the ligand pairs chelating the calcium with
phenoxide-O additionally bridging. The seven-coordinate
calcium atoms lie on the crystallographic 2 axis with
the water molecule, also on that axis, making up a seven-coordinate
environment. The tetrahydrate is also a one-dimensional polymer with a similar
spine, the bridging oxygen atoms derivative of water molecules. A chelating
ligand and two further water molecules make up an eight-coordinate metal
environment, with the free anions interleaving stacks of coordinated anions up
c.
Pigments of Fungi. XLIV Synthesis of Differentially Protected Chiral Pentane-1,3,5-triol Derivatives; Confirmation of the Absolute Configuration of Naturally Occurring 3-Acetoxy-2,3-dihydropiptoporic Acid
Authors: Burns, Christopher J. , Gill Melvyn , Saubern Simon
Published: August 2004

(R)-1-t-Butyldimethylsilyloxy-5-phenylmethoxypentan-3-ol
(25), prepared in 68% yield and >99·9% enantiomeric
excess over six steps from commercially available but-3-yn-1-ol by
Katsuki-Sharpless epoxidation, was converted by way of its 3-methoxymethyl
ether (30) into both enantiomers (6) and (11) of methyl
3,5-diacetoxypentanoate. Direct comparison of these substances with the ester
derived by oxidative degradation of the fungus pigment
3-acetoxy-2,3-dihydropiptoporic acid (1) confirmed the
(R) absolute configuration of the natural product. Some
new chemistry of the differentially protected chiral triols (12) and (30) is
described.
Flash Vacuum Pyrolysis of [2,3-13C2]Triphenylene-2,3-dicarboxylic Anhydride: Formation of Labelled Cyclopent[hi]acephenanthrylene and Triphenylene
Authors: Brown, Roger F. C. , Coulston Karen J. , Eastwood Frank W.
Published: August 2004

Flash vacuum pyrolysis (f.v.p.) of
[2,3-13C2]triphenylene-2,3-dicarboxylic
anhydride (c. 22·5%
13C2) at 950°C gave a
pyrolysate which was analysed by 13C n.m.r.
spectroscopy. The principal product was
[2,3-13C2]triphenylene.
The second major product was a 1 : 2 : 1 mixture of [4,7-
13C2]-,
[4,6-13C2]- and
[5,6-13C2]-cyclopent[hi]acephenanthrylene.
Serendipitous Isolation of a Trinuclear Silver Complex Containing a Bridging Tridentate Cyanide
Authors: Hartshorn Chris M. , Steel Peter J.
Published: August 2004

The X-ray structure of a single crystal of a complex of formula
C34H33Ag3N15O6
is described (P
21/c,
Z4, a 10·943(1),
b 33·873(5), c
10·416(2) Å, β 102·54(1)°, R
0·0363). The asymmetric unit of this compound contains three silver
atoms, two nitrate anions, a bridging tridentate cyanide ion, and one and a
half molecules of the bridging tetrapodal ligand
1,2,4,5-tetrakis(pyrazol-1-ylmethyl)benzene. By virtue of the bridging nature
of the ligand, these units further assemble into large macrocyclic rings, with
a maximum dimension of >24 Å. These rings then interlock to produce
an intriguing two-dimensional metallopolymeric network.
A Method for Calculating the Equilibrium Thermodynamic Properties of Gas Reaction Mixtures
Authors: McCoy Errol F. , Sykes Matthew J.
Published: August 2004

A computational method has been developed for determining the equilibrium
composition and thermodynamic properties of a multicomponent gas reaction
mixture. The method uses the downhill simplex method and simulated annealing
to minimize, subject to matter conservation, the total Gibbs energy of the
mixture with respect to its composition. The method has been used to examine
the properties of various high-temperature equilibrium mixtures of species
containing carbon, hydrogen, nitrogen and oxygen.
The Preparation and Crystal Structures of a Series of Urea Adducts: with Fumaric Acid (2 : 1), with Itaconic Acid (1 : 1) and with Cyanuric Acid (1 : 1)
Authors: Smith Graham , Kennard Colin H. L. , Byriel Karl A.
Published: August 2004

The adducts of a series of compounds with urea (ur) have been prepared and
their crystal structures determined by X-ray crystallography. These are the
adducts with the unsaturated aliphatic acids fumaric acid [(fumaric
acid)(ur)2] (1) and itaconic acid [(itaconic
acid)(ur)] (2), and with cyanuric acid [(cyanuric acid)(ur)]
(3). All structures have extensive hydrogen-bonding systems in which most of
the urea donor and acceptor sites are involved.
Diels - Alder Reactions of 1,1-Bis(methylthio)ethene with Pyran-2-ones.
Authors: Bates Robert W. , Pratt Andrew J. , Rendle Phillip M. , Robinson Ward T.
Published: August 2004

Bis(methylthio)ethene has been shown to undergo Diels–Alder
cycloaddition reactions with a range of simple and aryl-fused pyran-2-ones.
These reactions can be brought about under either high-temperature or
high-pressure conditions. These reactions are all regiospecific and in each
case only a single product is isolated, either the initial bridged adduct or
an aromatized product generated through decarboxylation. Although this
dienophile is less reactive than the corresponding oxygen analogue it is still
possible for cycloaddition chemistry to compete effectively with
decarboxylation chemistry.
Molecular Cocrystals of Carboxylic Acids. XXVIII. Nitro-Substituted Carboxylic Acids with Lewis Bases: the Crystal Structures of the Adducts of 3,5-Dinitrobenzoic Acid with N-Methylaniline (1 : 1), (4-Nitrophenyl)acetic Acid with Cyclohexane-1,4-diamine (2 : 1), and 5-Nitrosalicylic Acid with 2-Imidazolidone (2 : 1)
Authors: Smith Graham , Lynch Daniel E. , Bott Raymond C.
Published: August 2004

A number of molecular adducts of nitro-substituted aromatic acids with Lewis
bases have been prepared and characterized by infrared spectroscopy and in
three cases by X-ray diffraction methods. These three compounds are the
adducts of: 3,5-dinitrobenzoic acid (dnba) with
N-methylaniline (nma),
[(dnba)-(nma)+] (1);
(4-nitrophenyl)acetic acid (4-npa) with cyclohexane-1,4-diamine (dach),
[(4-npa)22-(dach)2+]
(4); 5-nitrosalicylic acid (5-nsa) with 2-imidazolidone (idaz),
[(5-nsa)2(idaz)] (5). Other compounds are the
adducts of 3,5-dinitrobenzoic acid with 2,6-dimethylpyridine (dmp),
[(dnba)(dnba)-(dmp)+]
(2), and with 1-methylpyrrole-2-carboxylic acid (cmp),
[(dnba)-(cmp)+] (3).
Compounds (1) and (3) have 1 : 1 stoichiometry, while (2), (4) and (5) are 2 :
1 adducts. Proton transfer occurs in most examples [complex (5) is the
exception].
Conversion of 12α-Hydroxyandrosta-1,4-diene-3,17-dione into a Derivative of 12-Oxoestradiol: a Novel C9 - C 10 Cleavage Reaction
Authors: Bourke David G. , Collins David J. , Bannister Jonathan D. , Doherty Carolyn L. , Fallon Gary D. , Lim Yvette , Ting Tina Lim Phaik , Ward Brent R.
Published: August 2004

Reaction of 12α-hydroxyandrosta-1,4-diene-3,17-dione (1) with
2,2-dimethylpropane-1,3-diol in the presence of pyridinium
p-toluenesulfonate gave the corresponding 17,17-cyclic
acetal (2). Oxidation of (2) with chromium trioxide in pyridine gave
5′,5′-dimethylspiro[androsta-1,4-diene-17,2′-[1,3]dioxan]-3,12-dione
(5) which underwent base-catalysed cleavage to give the novel 9,10-secosteroid
(8). Selective reduction of (1) at C17 gave
12α,17β-dihydroxyandrosta-1,4-dien-3-one (9a); selective protection
of this at C17, followed by oxidation with chromium trioxide in pyridine gave
17β-(t-butyldimethylsilyloxy)androsta- 1,4-diene-3,12-dione (10),
regioselectively protected as the 12,12-ethylenedioxy acetal (12). Treatment
of (12) with lithium in tetrahydrofuran in the presence of biphenyl and
diphenylmethane effected reductive aromatization of ring A to give a mixture
of
17β-(t-butyldimethylsilyloxy)-12,12-ethylenedioxyestra-1,3,5(10)-trien-3-ol
(15a) and the corresponding 17-alcohol (15b). Conversion of (15a) into the
corresponding 3-benzyl ether (14a), followed by acid-catalysed hydrolysis gave
12-oxoestradiol 3-benzyl ether (13).
Enolic Ortho Esters. VII Involvement of Magnesium Halides as Lewis Acids in the Reaction of Grignard Reagents with 1,6-Dideoxy- 1,1-ethylenedioxy-2,3,4-tri-O-methyl-D-xylo-hex-5- enopyranose and its 6-Phenyl Derivative: a Correction
Authors: Collins David J. , Hibberd Angus I. , Skelton Brian W. , White Allan H.
Published: August 2004

The known aldehyde methyl
2,3,4-tri-O-methyl-α-D-gluco-hexodialdo-1,5-pyranoside
(9) was converted in eight steps into the 6-phenyl glucose-derived enolic
ortho ester (Z)-1,6-dideoxy-1,1-ethylenedioxy-
2,3,4-tri-O-methyl-6-phenyl-D-xylo-hex-5-enopyranose
(22), the geometry of which was established by a single-crystal X-ray study.
Treatment of the 6-phenyl enolic ortho ester (22) with titanium tetrachloride
at –78° effected clean rearrangement into
(2R/S,4R,5R,6S)-3,3-ethylenedioxy-4,5,6-trimethoxy-2-phenylcyclohexanone
(26). Reaction of (22) with methylmagnesium iodide gave
(1R,2S,4R,5S,6S)-3,3-ethylenedioxy-4,5,6-trimethoxy-1-methyl-2-phenylcyclohexanol
(24), the structure and stereochemistry of which were established by an X-ray
study. Reaction of (22) with phenylmagnesium bromide gave (25), the 1-phenyl
analogue of (24). The firmly established structure of (24) led to proof both
chemically and by X-ray means that the product from reaction of
1,6-dideoxy-1,1-ethylenedioxy-2,3,4-tri-O-methyl-D-xylo-hex-5-enopyranose
(5) with methylmagnesium iodide has the hydroxy acetal structure (7) rather
than the originally assigned hemiacetal structure (3).
Bidentate Nitrogen Base Adducts of Bismuth(III) Nitrate
Authors: Barbour Leonard J. , Belfield Sarah J. , Junk Peter C. , Smith Matthew K.
Published: August 2004

Syntheses and single-crystal X-ray structure determinations are reported for a
number of adducts of bismuth(III) nitrate with the aromatic bidentate base
systems 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen). With bpy, a
mononuclear 1 : 2 adduct is formed,
[(bpy)2Bi(O2NO)3],
isomorphous with its rare earth counterparts, orthorhombic,
Pbcn, a 16·7634(8),
b 8·9970(4), c
15·0099(7) Å, Z = 4, conventional
R on |F|
0·029 for No 2502
independent ‘observed’ reflections. The Bi centre is 10-coordinate
with two bidentate N-base ligands and three bidentate nitrate ligands. With
phen the 10-coordinate 1 : 2 adduct
[(phen)2Bi(O2NO)3]
was readily obtained, while the 1 : 1 adduct proved elusive and a
hydroxide-bridged dimer
[(phen)(ONO2)2Bi(µ-OH)2Bi(O2NO)2(phen)]
with eight-coordinate Bi centres was the sole product from all crystallization
attempts.
[(phen)2Bi(O2NO3)3]
is monoclinic, C2/c,
a 11·258(5), b
17·847(4), c 13·044(5) Å, β
100·78(4)°, Z = 4,
R 0·063 for
No 1958, again isomorphous with
its rare earth counterparts;
[(phen)(ONO2)2Bi(µ-OH)2Bi(O2NO)2(phen)]
is triclinic, P-1,
a 8·3251(6), b
8·6315(6), c 10·7650(8) Å, α
111·120(1), β 93·486(1), γ 102·364(1)°,
Z = 1, dimer, R
0·024 for No 2965. In all
syntheses, dimethyl sulfoxide (dmso) was used as the supporting solvent; the
structure determination of the dmso adduct
[(dmso-O)3Bi(O2NO)3]
is also recorded where the Bi centre is nine-coordinate with three bidentate
nitrate ligands and three O-bound dmso ligands:
monoclinic
P21/n,
a 11·4136(6), b
12·6682(7), c 13·4959(7) Å, β
100·209(1)°, Z = 4,
R 0·026 for
No 4214.
Copper(II) Compounds with Amine Imine Ligands; Structures of (2,4,6,9,11-Pentamethyl-5,8-diazadodeca-4,8-diene-2,11-diamine)copper(II) Perchlorate and (2,4-Dimethyl-5,8,11- triazatridec-4-ene-2,13-diamine)copper(II) Perchlorate
Authors: Curtis Neil F. , Gladkikh Olga P. , Turnbull Mark M.
Published: August 2004

(2,4,6,9,11-Pentamethyl-5,8-diazadodeca-4,8-diene-2,11-diamine)copper(II)
perchlorate, formed by reaction of (propane-1,2-diamine)copper(II) perchlorate
with 4-amino-4-methylpentan-2-one, has the copper(II) ion in tetrahedrally
twisted [±0·23(1) Å] square planar coordination
by the tetradentate ligand, with a weak axial interaction with a perchlorate
ion with Cu–O 2·64(1) Å
[C15H32Cl2CuN4O8,
Mr 530·89, monoclinic,
space group
P21/n,
a 9·938(7), b
13·591(7), c 17·149(9) Å, β
106·65(5)°, Z 4,
R1 0·066 for 1096
reflections].
2,4-Dimethyl-5,8,11-triazatridec-4-ene-2,13-diamine)copper(II) perchlorate,
similarly formed from (triethylenetetramine)copper(II) perchlorate, has the
copper(II) ion in square pyramidal coordination by the pentadentate ligand
with the terminal primary amine group of the triamine residue in the axial
site with Cu–N 2·189(5) Å. The basal plane of four nitrogen
donor atoms is tetrahedrally twisted [±0·18(1)
Å], with the copper(II) ion displaced from this plane by
0·27(1) Å
[C12H29Cl2CuN5O8,
Mr 505·84, monoclinic,
space group
P21/c,
a, 9·934(2), b,
15·719(3), c, 13·688(3) Å, β
107·83(3)°, Z 4,
R1 0· 044 for 1485
reflections].
The Dichloroplatinum(II) Complex of 5,5,7-Trimethyl-1,4-diazacycloheptane: Preparation, Crystal Structure and Binding to Nucleotides and DNA
Authors: Teo Chih-Lynne , Fenton Ronald R. , Turner Peter , Hambley Trevor W.
Published: August 2004

The preparation of [Pt(tmdz)Cl2] (tmdz
= 5,5,7-trimethyl-1,4-diazacycloheptane) is described. The crystal
structure has been determined by X-ray diffraction methods and refined to an
R value of 0·048 (764F).
The crystals are triclinic, space group P
-1, a 8·023(2),
b 10·874(4), c
14·207(3) Å, α 95·34(3), β 94·96(2),
γ 94·97(3)°. N.m.r. studies and molecular mechanics methods
show that only one diastereomer of the complex—that observed in the
crystal structure—is energetically accessible. In total DNA binding
studies, [Pt(tmdz)Cl2] binds less effectively
and at a lower rate than cisplatin. The complex reacts
with dG and d(GpG) to form a variety of isomeric products, as indicated by
h.p.l.c. analysis.
Copper(II) Compounds of 5-Alkyl-3,5,7-triazanonane-1,9-diamines and 3,10-Bisalkyl-1,3,5,8,10,12-hexaaza-cyclotetradecanes; the Structure of 1R,5S,8R,12S-{3,10-Bis(2-hydroxypropyl)-1,3,5,8,10,12-hexaaza-cyclotetradecane-N1,N5,N8,N12} copper(II) Perchlorate
Authors: Anastasi David , Curtis Neil F. , Gladkikh Olga P. , Goode Timothy J. C. , Weatherburn David C.
Published: August 2004

Preparations are reported for
(3,10-bisalkyl-1,3,5,8,10,12-hexaazacyclotetradecane)copper(II) perchlorates
(alkyl = propyl, 1-methylethyl, butyl, cyclohexyl,
2-(diethylammmonio)ethyl, 2-hydroxyethyl, 3- hydroxypropyl and
2-hydroxypropyl) by reaction of bis(ethane-1,2-diamine)copper(II) perchlorate
with methanal, and alkylamines. The structure of
{3,10-bis(2-hydroxypropyl)-1,3,5,8,10,12-hexa-azacyclotetradecane}copper(II)
perchlorate is reported
[C14H34Cl2CuN6O10,
monoclinic, space group
P21/c,
a 8·504(2), b
14·855(5), c 9·034(2) Å, β
98·99(2)°, Z 2,
R1 0· 061 for 1667
reflections]. The centrosymmetrical cation has a mean Cu–N distance
of 2·001(4) Å, with perchlorate ion oxygen atoms weakly
coordinated in the axial sites with a Cu–O distance of 2·61(1)
Å. The planar copper(II) macrocycle cations form stacks which are linked
by N–H · · · O and O–H · ·
· O–ClO3 hydrogen bonds involving the
extended 2-hydroxypropyl substituents, with no interaction between the
copper(II) ion and the hydroxy groups.
(5-Alkyl-3,5,7-triazanonane-1,9-diamine)copper(II) perchlorate compounds with
the same 3-substituent alkyl groups (plus methyl, and ethyl, and also phenyl)
are similarly prepared by using 1 mole proportion of the amine and 2 mole
proportions of methanal
Macrocyclic Ligand Design. Structure - Function Relationships Underlying the Interaction of Zinc(II), Cadmium(II), Silver(I) and Lead(II) with Mixed-Donor Macrocyclic Ligands
Authors: Davis Carol A. , Kim Jeong , Lindoy Leonard F. , Lee Seong-Hwa , Leong Anthony J.
Published: August 2004

An investigation of the interaction of zinc(II), cadmium(II), silver(I) and
lead(II) with a series of mixed-donor dibenzo-substituted macrocyclic ligands,
incorporating O2N3-,
O2N4-,
O3N2-,
O3N3-,
O4N2- and
O2N3S-donor sets, has been carried
out. The log K values for the respective complexes in
95% methanol (I = 0·1;
Et4NClO4, 25°C) have been
determined potentiometrically. All ligands form 1 : 1 (metal/ligand)
complexes with the above metal ions although in isolated cases species of type
MLH2+ were also observed. An investigation of the effect
of variation of ligand structure on the respective complex stabilities has
been carried out and the results compared with those obtained previously for
closely related mixed-donor macrocyclic systems.
The binding of silver(I) and lead(II) to the 17- and 18-membered
O3N2-ligand systems has been
assessed in (CD3)2SO by means of
13C n.m.r. spin–lattice relaxation
(T1) studies as well as by
observation of the induced chemical shifts of particular ligand resonances on
complex formation. Overall, the n.m.r. results correlate well with the
observed thermodynamic stabilities of the individual complexes.
The Preparation and Crystal Structures of the 1 : 1 Adducts of 5-Nitrosalicylic Acid and 2-Chloro-3,5- dinitrobenzoic Acid with Triphenylphosphine Oxide
Authors: Smith Graham , Lynch Daniel E. , Kennard Colin H. L. , Byriel Karl A.
Published: August 2004

The (1 : 1) adducts of 5-nitrosalicylic acid (5-nsa) and
2-chloro-3,5-dinitrobenzoic acid (cdnba) with triphenylphosphine oxide (tppo),
[(5-nsa)(tppo)] (1) and [(cdnba)(tppo)] (2), have been
prepared and their structures determined by X-ray diffraction and reffned to
residuals R 0·045 (1) and 0·043 (2) for
2540 and 3265 observed reflections respectively. Crystals of both adducts are
monoclinic, space group
P21/c
(1) and
P21/a
(2), with 4 dimer units in cells of dimensions a
16·217(1), b 7·6807(8),
c 19·697(4) Å, β 113·357(8)°
[for (1)] and a 16·009(5),
b 8·687(1), c
17·640(5) Å, β 90·30(1)o
[for (2)]. In both examples, the two molecules comprising the
asymmetric unit are linked by a single hydrogen bond between the proton of the
carboxylic acid and the phosphoryl oxygen of tppo [O- - -O,
2·524(3) Å (1); 2·72(3) Å (2)], while, in each
case, the additional functional groups of the acid are not involved in any
other intermolecular hydrogen-bonding interactions.
Coordination of the Strong Field Terimine System 6-Triazol-3-yl-2,2′-bipyridine and Substituted Derivatives. Electronic and Structural Properties of Bis(ligand)iron(II) Complexes
Authors: Childs Bradley J. , Craig Donald C. , Scudder Marcia L. , Goodwin Harold A.
Published: August 2004

A terminal pyridine ring in terpyridine has been replaced by a triazole or
substituted triazole moiety to give the tridentates
6-(1,2,4-triazol-3-yl)-2,2´-bipyridine,
6-(1-methyl-1,2,4-triazol-3-yl)-2,2´-bipyridine,
6-(5-methyl-1,2,4-triazol-3-yl)-2,2´-bipyridine and
6-(1,5-dimethyl-1,2,4-triazol-3-yl)-2,2´-bipyridine. The effects of
coordination of these on the electronic and structural properties of the
[FeN6]2+ species are
considered. The primary effect is a reduction in the ligand field but salts of
the [FeN6]2+ derivatives
are essentially low spin (singlet ground state) at room temperature. A small
and temperature-dependent population of quintet state species is indicated by
Mössbauer spectra but in no instance is a complete singlet → quintet
transition observed up to 383 K. The electronic spectra of the
[FeN6]2+ species are
similar to that of
[Fe(trpy)2]2+ but the
energy of the charge-transfer transition is higher, indicating less effective
metal ion → donor π-interaction than in the terpyridine complex.
Consistent with this, the Mössbauer isomer-shift values are greater than
for [Fe(trpy)2]2+ and
the E½ values for the
[FeN6]3+
/[FeN6]2+ couples
are less positive than for
[Fe(trpy)2]2+.
Structural data reveal average Fe–N distances normal for low-spin
iron(II) but with greater distortion of the coordination environment than in
[Fe(trpy)2]2+. When
present, the >NH group of the triazole moiety is hydrogen-bonded to solvate
water and the anion in the hydrated tetrafluoroborate salts.
Bis(6-(1,2,4-triazol-3-yl)-2,2´-bipyridine)iron(II) tetrafluoroborate
tetrahydrate: monoclinic, space group
P21/c,
a 15·917(7), b
18·432(5), c 10·845(5) Å, β
94·36(2)°, Z 4;
bis(6-(1-methyl-1,2,4-triazol-3-yl)-2,2´-bipyridine)iron(II)
tetrafluoroborate: triclinic, space group P−1,
a 11·68(1), b
11·96(2), c 12·46(2) Å, α
82·93(8), β 72·30(9), γ 68·49(10)°,
Z 2;
bis(6-(5-methyl-1,2,4-triazol-3-yl)-2,2´-bipyridine)iron(II)
tetrafluoroborate monohydrate: monoclinic, space group
P21/c,
a 10·715(4), b
25·818(5), c 11·039(4) Å, β
90·08(2)°, Z 4;
bis(6-(1,5-dimethyl-1,2,4-triazol-3-yl)-2,2´-bipyridine)iron(II)
triflate tetrahydrate: orthorhombic, space group P
bcn; a 20·654(6),
b 11·618(3), c
16·080(6) Å, Z 4.
A Facile Synthesis of 2,6-Dideoxy 6,6,6-Trifluorinated Carbohydrate Analogues
Authors: Hayman Colin M. , Larsen David S. , Brooker Sally
Published: August 2004

The syntheses of
2,6-dideoxy-6,6,6-trifluoro-DL-arabino-hexose (4) and
the corresponding glycoside, ethyl
2,6-dideoxy-6,6,6-trifluoro-DL-arabino-hexopyranoside
(11), are described. The key step in the synthesis of (4) involved the Lewis
acid catalysed hetero-Diels–Alder reactions of
(E)-4-benzyloxy-1,1,1-trifluorobut-3-en-2-one and benzyl
vinyl ether. Hydroboration of the resulting cycloadduct, and hydrogenylitic
debenzylation gave (4) in a 59% overall yield. The ethyl glycoside (11)
was prepared in a similar manner from ethyl vinyl ether. A single-crystal
X-ray diffraction study confirmed the structural assignment of (11). The
O-glycosides (17) and (18) were formed from the boron
trifluoride etherate promoted reaction of the per-acetate of (4), i.e. (16),
and 2-naphthol. However, a similar reaction between
5-hydroxy-1,4-dimethoxynaphthalene and (16) gave the disubstituted
C-glycoside (19) in 52% yield.
N-Alkylation of Pyromellitic Diimide: Solid-State Structure of the 1 : 1 N,N′-Diethylpyromellitic Diimide/2,6-Dimethoxynaphthalene Cocrystal
Authors: Hamilton Darren G. , Lynch Daniel E. , Byriel Karl A. , Kennard Colin H. L. , Sanders Jeremy K. M.
Published: August 2004

N-Alkylation of pyromellitic diimide in the presence of
CsF affords N-substituted diimide derivatives that lack
the hydrogen-bonding ability of the parent diimide. The solid-state structure
of the
N,N′-diethylpyromellitic
diimide/2,6-dimethoxynaphthalene donor{acceptor complex reveals the
influence of removing this hydrogen-bonding ability on the crystal packing.
Structure and Binding Properties of Four New Oligomeric Cyclophane Esters: 1,4-Xylylene 1,4-Phenylene Diacetates and Dipropionates
Authors: Donati Donato , Roelens Stefano , Torriti Riccardo , Valle Giovanni
Published: August 2004

The X-ray crystal structure determinations of four new oligomeric cyclophane
esters are reported. They are: (3a) monomeric 1,4-xylylene
(1,4-phenylene)diacetate,
P21/n
(No. 14), a 5·959(5), b
15·795(5), c 8·094(5) Å, β
108·060(5)°, V 724·3(8)
Å3 , Z 2,
R1(2σ) 0·0522,
wR2 0·125; (3b) monomeric
1,4-xylylene (1,4-phenylene)dipropionate,
P21/c
(No. 14), a 5·878(1), b
14·642(2), c 18·909(2) Å, β
96·00(10)°, V 1618·5(4)
Å3 , Z 4,
R1(2σ) 0·053,
wR2 0·165; (3c) dimeric
1,4-xylylene (1,4-phenylene)diacetate,
P-1 (No. 2),
a 14·633(2), b
17·529(2), c 5·736(1) Å, α
98·30(10), β 90·60(10), γ 95·40(10)°,
V 1449·0(4) Å3,
Z 2,
R1(2σ) 0·057,
wR2 0·158; (3d) dimeric
1,4-xylylene (1,4-phenylene)dipropionate,
P21/a
(No. 14), a 8·145(1), b
11·379(2), c 17·401(2) Å, β
101·40(10)°, V 1580·9(4)
Å3, Z 4,
R1(2σ) 0·034,
wR2 0·095. Monomeric
cyclophanes (3a,b) exhibit a well defined cleft, while dimeric (3c,d) adopt a
flat conformation devoid of cavities. Binding properties were determined by
1H n.m.r. titrations in CDCl3 at
T = 296 K. Complexation experiments with
quaternary ammonium salts revealed that host (3c) possesses appreciable
binding ability toward N-methylpyridinium
(–ΔG° = 5·9 kJ
mol-1), tetramethylammonium
(–ΔG° = 8·8 kJ
mol-1) and acetylcholine
(–ΔG° = 7·5 kJ
mol-1) cations, despite its lack of a preorganized
cavity.