bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas-Phase Ion Chemistry of Siloxide and Silamide Ions by Using the Flowing Afterglow. Unusual Rearrangements Involving SiO and SiS Bond Formation
Authors: Ohair RAJ , Sheldon JC , Bowie JH , Damrauer R , Depuy CH
Published: September 2010

Siloxide ions undergo O/S exchange reactions with suitable sulfur-containing neutrals, e.g. H3SiO-+CS2 → H3SiS-+COS. Silamide ions similarly undergo NR/O and NR/S exchange reactions together with nucleophilic displacement reactions, e.g. Me3SiNMe + CO2 → Me3SiO-+MeNCO →No simple correlation between rate and mechanism is observed for all the studied reactions.
Photochemical cis-trans Isomerization of 2-Substituted 9-(2-Nitroethenyl)anthracenes. X-Ray Structure Analyses of (E)- and (Z)-9-(2-Nitro-2-phenylethenyl)anthracene
Authors: Becker HD , Skelton BW , Sorensen H , White AH
Published: September 2010

(E)-9-(2-Nitropropeny1)anthracene and (E)-9-(2-nitro-2-phenylethenyl)anthracene have been prepared by piperidine-catalysed condensation of 9-anthraldehyde with nitroethane and nitro(phenyl)methane, respectively. The corresponding (Z)-compounds were obtained by photochemical isomerization, quantum yields of geometrical isomerlzation being measured in cyclohexane, benzene, dichloromethane and ethanol. In
virtually all solvents the (Z)-isomers are favoured at the photostationary state. The structures of (E)- and (2)-942- nitro-2-phenylethenyl)anthracene have been established by single-crystal X-ray diffraction studies.
Molecular Structures of Di(9-anthryl)Methanol and Di(9-anthryl) Ketone
Authors: Becker HD , Langer V , Skelton BW , White AH
Published: September 2010

The molecular structures of di(9-anthryl)methanol (1) and di(9-anthryl) ketone (2) have been established by X-ray diffraction. The asymmetric unit of di(anthryl)methanol consists of two molecules in which the dihedral angle between the anthracene moieties is 81.4 and 86.3 respectively; steric interaction between the anthracene moieties results in them subtending angles of 115.0(7) and 115.8(8)� at the central carbon atom, and with unsymmetrical exocyclic angles at their point of attachment. In di(9-anthryl) ketone the planes of the anthracene systems are twisted out of the plane of the carbonyl group by 48.8 and 52.2� respectively, so that the dihedral angle between the two aromatic ring systems is 87.3�. The structures of di(anthryl)methanol and di(anthryl) ketone are discussed with respect to their different modes of photochemical isomerization by intramolecular cycloaddition.
Lewis-Base Adducts of Group 11 Metal(I) Compounds. L. Heterobimetallic Tris(dithiocarbamato)metal(III)/Copper(I) Iodide Adducts [Metal(III) = Cr, Rh]
Authors: Engelhardt LM , Healy PC , Skelton BW , White AH
Published: September 2010

A variety of heterobimetallic adducts formed between tris(dithiocarbarnato)cobalt(lII) complexes and copper(1) halides have been recorded. In the present paper, reports of the synthesis and structure determinations of [Rh {S2CN(CH2)4}3]3Cul (1), [Cr(S2CNEt2)3]. [Cr(S2CNEt2)3] and [Cr{S2CN(CH2)4}3].3Cul.MeCN (3), similar to cobalt(llI) counterparts, suggest that, in principle, the previously described chemistry of the cobalt(III) systems may be extended to analogous systems for dithiocarbamates of any non-labile trivalent metal. The novel Cu3I3 ring of (3) is disordered between possible boat forms.
Lewis-Base Adducts of Group 11 Metal(I) Compounds. LV. Synthesis and Structures of 1 : 1 Copper(I) Halide (Cl, Br, I)/2-Aminoquinoline Complexes
Authors: Engelhardt LM , Healy PC , Kildea JD , Skelton BW , White AH
Published: September 2010

1 : 1 Adducts of the copper(I) halides, CuX (X=CI, Br, I), with 2-aminoquinoline (amq) have been synthesized by the crystallization of stoichiometric mixtures of these components from acetonitrile solution, and their structures determined by single-crystal X-ray methods; they are found to span a diverse array of structural types. The chloride crystallizes as a 'stair polymer' array [monoclinic, P21, a 7.487(6), b 3.771(7), c 15.506(2) � , 95.07(4)�, Z= 2]. The bromide is a centrosymmetric dimer , solvated by acetonitrile, [( amq )( MeCN )CuBr2Cu( MeCN )( amq )] [triclinic, PI, a 17.325(8), b 10.376(3), c 7.204(9) �, α 70.36(6), β 88.13(7), γ 77.52(3) �, Z= 2 dimers]; Cu-Br range from 2.551(2)-2.668(2); Cu-N( amq ) are 2.021(8), 2.010(6); Cu-N( MeCN ) are 1.986(8), 1.960(7) A (two independent dimers ). The iodide alone forms the expected single-strand 'split-stair' polymer [monoclinic, P21, a 12.090(5), b 9.971(5), c 4.132(2) � , P 98. 50(3) �, Z = 21, Cu-I, 2.527(3), 2. 567(3); Cu-N, 2.02(2) � . Residuals were 0.035, 0.050, 0.045 for 552, 2974, 608 independent 'observed' reflections respectively.
Structural Characterization of the Reaction Products of Vanadium(II) and Endrin as 2 Isomers of 1,8,exo-9,10,11-Pentachloropentacyclo[6.2.1.13,6.02,7.04,10]dodecan-5-one
Authors: Clegg DE , Healy PC , Patch GJ , Skelton BW , White AH
Published: September 2010

Two dechlorinated products (B) and (D), formed in the reaction between endrin (C12H8Cl6O) and vanadium(II) for the purpose of confirmation of identity, are shown by single-crystal X-ray structure determination to be isomers of the title compound, C12H9Cl5O. Crystals of both are monoclinic, P21/c. For isomer (B), a 7.432(8), b 12.76(1), c 14.55(2) � , β 108.32(9)�, Z=4; R was 0.038 for 2594 observed reflections. For isomer (D), a 9.037(4), b 12.004(4), c 14.436(6) � , β 124.91(2)°, Z= 4; R was 0.041 for 1826 reflections. The geometries of the two isomers are compared.
Formation and Molecular-Structures of meso-1,2-Bis(9-anthryl)-1,2-diacetoxyethanes
Authors: Becker HD , Hansen L , Skelton BW , Sorensen H , White AH
Published: September 2010

The molecular structures of meso-1,2-diacetoxy-1,2-di(9-anthryl)ethane (1) and meso-1,2-diacetoxy-1,2-di(10-acetoxy-9-anthryl)ethane (2) have been established by X-ray diffraction. Their molecular conformations are characterized by a staggered arrangement of substituents about the central ethane linkage, and anti-orientation of the anthracene moieties. The dianthrylethane derivative (1) was isolated in two crystalline modifications, (1a) and (1b), whose different crystal luminescence properties are correlated with the differences in packing pattern.
Terpenoid Chemistry. XXVIII. Furanosesquiterpene β-Ketols From Myoporum betcheanum, M. deserti, M. montanum and Other Myoporaceae
Authors: Sutherland MD , Rodwell JL
Published: September 2010

All four of the myodesmoid β-ketols (la) formally derivable from (-)-(S)-myoporone (3a),three of the four myomontanoid β-ketols (2a) from ent-(3a) and two of the four 10,ll-dehydro myodesmoid β-ketols (lb) from (3b), have been found in Myoporaceous plants and characterized by g.1.c. retentions and by Kovats indices and mass spectra of their trimethylsilyl ethers. Five of these ketols have been obtained as crystalline solids whose stereochemistry has been determined in part. All are readily converted into myoporone or 10,11-dehydromyoporone by pyrolysis during distillation or gas chromatography, and by base or alumina. These facile ring-opening reactions have previously concealed the widespread occurrence of these furanosesquiterpene β-ketols in the Myoporaceae. In the few specimens of Myoporum betcheanum, M. deserti and M. montanumwhich have been suitably examined, the β-ketols form a complex mixture of from four to eight ketols differing in carbon skeleton, unsaturation and/or stereochemistry. P-Ketols have been recognized in eight species of Myoporum and three of Eremophila. Both enantiomers of one myodesmoid ketol have been isolated. A mixture of ketols showed a toxicity similar to that of (-)-ngaione. A quick and quantitative micro method for the preparation of g.l.c.-injectable carbon disulfide solutions of volatile leaf constituents is described.
The Crystal-Structure of Bis[Aquabis(4-amino-3,5,6-trichloropyridine-2-carboxylato)silver(I)] Dihydrate
Authors: Calos NJ , Kennard CHL , Mak TCW , Smith G
Published: September 2010

The crystal structure of the silver(I) complex of the herbicide Picloram, silver(1) 4-amino- 3,5,6-trichloropyridine-2-carboxylate dihydrate, has been determined by X-ray diffraction at 293 K, and refined to a residual R 0.037 for 2583 observed reflections. The triclnic crystal has the cell dimensions a 7.1197(8), b 8.924(2), c 9.493(1) �, α 95.84(1), β 105.71(1), γ 108.68(1)�, with space group P1, and contains one dimer per unit cell. Silver has a distorted tetrahedral coordination and is bound to the pyridyl nitrogen [Ag-N, 2.313(3) �], an oxygen of the carboxy group [Ag-O, 2.362(2) �], and one water molecule [Ag-O, 2.195(3) �]. The carboxyl oxygen atoms bridge two silver atoms [Ag-O′, 2.810(2) �] forming a centrosymmetric dimer . The other water molecule is present as a molecule of solvation , hydrogen-bonded to the amino group of the picloramate ligand [O-N, 2.881(4) �].
Argon Matrix Study of the Infrared Spectrum of Butatrienone
Authors: Brown RFC , Coulston KJ , Eastwood FW , Pullin ADE , Staffa AC
Published: September 2010

Butatrienone, H2C=C=C=C=O, was generated by pyrolysis of each of six different precursors in a stream of argon at temperatures in the range 710-880°C, and the pyrolysate-argon mixture was condensed on a Csl plate at c. 10 K. Infrared spectra were obtained between 4000 and 250 cm-1. Two precursors, buta-2,3-dienoic trifluoracetic anhydride (1) and buta-2,3-dienoyl chloride (2), gave pyrolysates showing a spectrum consisting of six strong bands and five weak bands. Four precursors, bicyclo [2.2.1]hept-5′-en-2′-ylideneacetic trifluoracetic anhydride (3), 5-( bicyclo [2.2.1]hept-5′-en-2′-ylidene)-2,2-dimethyl-1,3-dioxan-4,6- dione (4),2,2-dimethyl-5-(7?-oxabicyclo[2.2.1]hept-5?-en-2?-ylidene)- 1,3-dioxan-4,6-dione (5) and 3,4-diazatricyclo[5.2.1.02,6]deca-3,8-diene-endo-cis-2,6-dicarboxylic anhydride (6) gave pyrolysates showing spectra consisting principally of the six strong bands. The observed bands assigned to matrix-isolated butatrienone were at 3105w, 3035s, 3010w, 2964w, 2242s, 1996w, 1495s, 1456s, 728s, 404w cm-1. Calculated frequencies, using various models, for butatrienone are reported and are used to make plausible assignments. The strongest band (v2) attributed to butatrienone was at 2242 cm-1 which was shifted to 2200 cm-1 in (1-13C) butatrienone.
The Application of Supercomputers in Modeling Chemical Reaction Kinetics: Kinetic Simulation of 'Quasi-Living' Radical Polymerization
Authors: Johnson CHJ , Moad G , Solomon DH , Spurling TH , Vearing DJ
Published: September 2010

A computer program has been written which employs an implicit Euler method to solve directly the complete set of coupled differential equations which result from an analysis of polymerization kinetics. The program was written to make full use of the speed and power of modern supercomputers, and is suited to the solution of very large stiff systems of differential equations. The benefit of treating each propagation step as a discrete reaction is that information on the evolution of the molecular weight distribution is obtained directly without the need to make perhaps unjustified assumptions such as the steady-state approximation. For illustrative purposes, the method has been applied in the kinetic simulation of 'quasi-living' radical polymerization to assess the effect of experimental variables on the molecular weight, molecular weight distribution, and rate of polymerization. The calculations show that 'quasi-living' radical polymerization can produce polymers with polydispersities approaching those obtained with anionic 'living' polymerizations. Some necessary conditions for the formation of polymers with narrow molecular weight distribution are defined.
5,7-Dichloro-3-O-methylnorliche-xanthone, a New Xanthone From the Lichen Lecanora broccha
Authors: Elix JA , Jiang H
Published: September 2010

5,7-Dichloro-1,6-dihydroxy-3-methoxy-8-methyl-9H-xanthen-9-one (7) (5,7-dichloro-3-O-methylnorlichexanthone) has been synthesized and shown to cooccur with 2,5,7-trichloro-3-O-methylnorlichexanthone (6) in the lichen Lecanora broccha.
Coordination of 3,3'-Bipyridazine With Bivalent Copper, Palladium and Platinum
Authors: Goodwin HA , Onggo D , Skelton BW , White AH
Published: September 2010

Bis ( ligand ) complexes of the diimine 3,3′-bipyridazine (L) with bivalent copper, palladium and platinum are described. Green and violet forms of [CuL2] [BF4]2 were obtained, and the electronic and vibrational spectra suggest coordinated fluoroborate groups in the violet species. In the green complex a tetragonal structure is indicated. Coordination of perchlorate in [PdL2] [ClO4]2 is also indicated but not in [PtL2] [ClO4]2. Structure determination of the latter complex reveals a strictly planar PtN4 moiety, and in fact the whole complex cation is approximately planar. Reduced interligand repulsions, compared to those operative in bis ( ligand ) complexes of 2,2?-bipyridine, are believed to allow the essentially planar conformation. The structure of [PtL2] [ClO4]2 was determined at 295 K by single-crystal X-ray diffraction methods, and was refined to a residual of 0.033 for 1942 'observed' independent reflections. Crystal data: [PtL2][ClO4]2 monoclinic, space group P21/c (C5/2h, No. 14), a 7.919(2), b 13.086(3), c 10.313(3)Ǻ, β 107.16(2)°.
Morphology and Pore Structure of Rare Earth Oxides
Authors: Bruce LA , Hoang M , Hardin S , Turney TW
Published: September 2010

The morphology observed by transmission electron microscopy of rare earth oxides, prepared by two different routes, has been related to adsorption characteristics for nitrogen at 77 K. The most common morphology was that of thin sheets, then small equiaxed particles, and, more rarely, rod-like particles. The presence of small equiaxed particles was found to be a prerequisite for adsorption hysteresis. Evaluation of linear 't' plots indicated freedom from micropores in all samples, but positive deviations in the presence of sheet morphology at high relative pressures left open the possibility of wedge-like pores in these samples.
Solid-State 31P N.M.R. and Crystal Structure of Binuclear Di-μ-chloro-bis[(4-methylpyridine)(triphenyl-phosphine)copper(I)]
Authors: Healy PC , Whittaker AK , Kildea JD , Skelton BW , White AH
Published: September 2010

The 1 : 1 : 1 adduct of 4-methylpyridine (MeC5H4N), triphenylphosphine and copper(I) chloride has been synthesized, and characterized by solid-state 31P CP-MAS n.m.r. and a single-crystal X-ray structure determination. The structure determination reveals the presence of two crystallographically independent but pseudo-symmetrically related [(PPh3)(MeC5H4N) CuCl ]2 molecules in the unit cell, with the [(MeC5H4N) CuCl ]2 core and PPh3 ligands adopting different dispositions in each dimer. Crystals of the compound are triclinic, with space group Pī , a 16.884(5), b 14.898(4), c 9.501(3)Ǻ , α 104.28(2), β 89.95(2), γ 111.25(2)°. This structure refined to a final residual of 0.041 for 3022 'observed' [I> 3σ(I)] reflections. Cu- P,Cl,Cl,N are 2.196(2), 2.395(2), 2.402(3), 2.061(5)Ǻ for molecule 1 and 2.197(2), 2.420(2), 2.386(3), 2.061(5)Ǻ for molecule 2. The n.m.r. data show quartets arising from two crystallographically independent phosphorus atoms coupled to copper(I) atoms. The chemical shift difference between the quartets is 2.5 ppm. Line spacings of 1.546-1.746 kHz are indicative of [PPh3Cu]+ with the copper atoms in a tetrahedral environment. n.m.r. data have been recorded also for the analogous dimeric systems, [(PPh3)(RC5H4N) CuCl ]2 (R = H, 4-CN). Comparison of the n.m.r. data is made with analogous data for other compounds containing the [(PPh3)Cu]+ molecular fragment.
The Crystal Structure of Dimethyl (1aα,2aα,5β,6aβ-Hexahydroazirino[2,1-b]benzoxazole-1a, 5(1H)-dicarboxylate
Authors: Mackay MF , Campbell M , Mcleish MJ
Published: September 2010

The title compound formed the major component in a rearrangement of an analogue of 4-amino-4-deoxychorismic acid (1), an intermediate in the chorismate-p-aminobenzoic acid biotransformation. X-Ray crystallographic analysis has defined the relative stereochemistry at the four chiral centres in the tricyclic molecule.
Tetraazacycloalkanes With Pendant Carboxylates. Copper(II)-Directed Syntheses and Crystal Structure of (Ethyl 1,5,9,13-tetraazabicyclo[11.2.2]heptadecane-7-carboxylate)copper(II) Perchlorate
Authors: Lawrance GA , Skelton BW , White AH , Wilkes EN
Published: September 2010

Reaction of copper(II) complexes of the tetraamines H2N-(CH2)n-NH-(CH2)m-NH-(CH2)n-NH2 (n, m=5, 6), N,N′- bis (3-aminopropyl)-1,4-diazacyclohexane and ethane-1,2-diamine with formaldehyde and diethyl malonate in methanolic base produces macrocycles where initially new -NH-CH2-C( COOEt )2-CH2-NH-links are built by joining the cis-disposed primary amines in the precursor complexes. Under the basic conditions of the reaction, the macrocyclic product may be isolated not simply with gem ethoxycarbonyl groups, but as the carboxy ethoxycarbonyl, or even with a single carboxy pendant or its ester following ester hydrolysis and/or decarboxylation reactions. All diesters or acid esters can be hydrolysed conveniently to the stable monoacid in aqueous base, producing complexes of macrocyclic tetraamines with a single carboxylate group pendant to the ring at the central carbon of a propyl chain. Physical properties of the copper(II) complexes are reported and compared with analogues where a nitro group is pendant to the ring rather than the carboxylate group. The (ethyl 1,5,9,13-tetraazabicyclo[11.2.2]heptadecane-7-carboxylate)copper(II) perchlorate monohydrate was crystallized in the monoclinic space group P 21/c, a 8.968(3), b 8.435(3), c 32.007(11)Ǻ, β 99.18(3)°, Z = 4, and a single-crystal X-ray structure determination refined to R 0.045 for 2631 'observed' reflections. The copper ion exists in a square pyramidal geometry of four nitrogen donors and a perchlorate anion oxygen, with a quite short Cu-O distance (2.30Ǻ). The Cu-N(secondary) and Cu-N(tertiary) distances are 2.037(4), 2.035(4), and 2.082(4), 2.062(4)Ǻ respectively.
Lewis-Base Adducts of Group 11 Metal(I) Compounds. Synthesis and Structural Characterization of Some Halopyridin/triphenylphosphinesilver(I) Complexes: Some Space Group Revisions for Parts LII-LIV
Authors: Effend y , Engelhardt LM , Healy PC , Skelton BW , White AH
Published: September 2010

Redetermination of the room-temperature crystal structures of mononuclear chloro- and bromo-pyridinebis ( triphenylphosphine )silver(I) (previously described in space group P21/m) and di-μ-iodo-bis [(pyridine)( triphenylphosphine )silver(I)](previously described in space group C2/m), consequent upon the availability of crystals of improved quality, has permitted the reassignment of space groups as P21/a (with doubled a axis) and C2/c respectively, by virtue of the facilitated detection of weak superlattice reflections. Crystals of [ Cl,BrAg ( py )(PPh3)2] are monoclinic, P21/a, a ≈ 19.6, b ≈ 20.0, c ≈ 9.1Ǻ, β ≈ 97.5°, Z = 4; the structures were refined to residuals of 0.034 and 0.040 for 2965 and 2315 'observed' reflections respectively. [(PPh3)( py )AgI2Ag( py )(PPh3)] is monoclinic, C2/c, a 27.145(6), b 14.548(3), c 11.316(4)Ǻ, β 94.83(2)°, Z 4, refining to R 0.035 for 1892 'observed' reflections, and isomorphous with the [(PPh3)( py )CuX2Cu( py )(PPh3)] family. In spite of this reassignment, the previous descriptions of the AgX /N/P cores of the species are essentially unchanged, the previous residuals of the misassigned space group determinations being comparable with the present; the only non- trivial change lies in the fact that the disordered phenyl rings of the earlier work are now fully ordered. It now seems certain that the 'second polymorph' of [(PPh3)( py )CuBr2Cu( py )(PPh3)], recorded as being isomorphous with its C2/m silver iodide counterpart, is spurious and a consequence of the use of an inferior specimen.
(+)-14β-Hydroxylabda-8(17),12-dieno-16,15-lactone [(+)-Isocoronarin-D]: a New Diterpene From Hedychium coronarium (Zingiberaceae)
Authors: Singh S , Gray AI , Skelton BW , Waterman PG , White AH
Published: September 2010

An investigation of the rhizome of Hedychium coronarium ( Zingiberaceae ), collected in the Kathmandu Valley, Nepal, has yielded coronarin -D, coronarin -D ethyl ether, coronarin -E, and a new diterpene identified as (+)-14β-hydroxylabda-8(17),12-dieno-16,15-lactone, assigned the trivial name of isocoronarin-D. The structure of isocoronarin-D (3) was determined by spectroscopic and X-ray crystallographic studies.
Compounds of (1,4,8,11-Tetraazacyclotetra-Decane)Copper(II) With 6-Carbamoyl and 13-Carbamoyl, -Methylcarbamoyl, -Ethylcarbamoyl and -Hydrazinocarbonyl Substituents
Authors: Xin L , Curtis NF
Published: September 2010

The (dimethyl trans-1,4,8,1l-tetraazacyclotetradecane-6,13-dicarboxylate)copper(II) cation reacts with ammonia, methylamine or hydrazine to give the dicarbamoyl-, di(methylcarbamoyl)- or di(hydrazinocarbonyl)-substituted complex cations, respectively. The 6,6,13,13-tetra(methoxy- carbonyl)-substituted compound reacts with ammonia at O�C to form the tetracarbamoyl- substituted macrocycle compound [which can also be prepared by condensation of bis(ethane-1,2-diamine)copper(II), formaldehyde and malondiamide], and the dicarbamoyl dicarboxylic acid compound at higher temperatures. Reaction of the tetra(ethoxycarbonyl) compound with ammonia yields a variety of products, depending upon conditions. Reaction of the tetra (ethoxycarbonyl) compound with methylamine yields the di(N- methylcarbamoyl) di(carboxy1ato) substituted macrocycle compound. Condensation of bis(ethane-1,2-diamine)copper(II), formaldehyde and N,N1-diethylmalondiamide yields the tetra(ethylcarbamoyl)-substituted macrocyle compound. A similar reaction with N,N1- dimethylmalondiamide yields a compound with a methylene group additional to the tetra(methylcarbamoyl) formulation.
Structure Systematics of Auxin Herbicides. XXX. The Crystal Structures of (2-Isopropylphenoxy)-acetic Acid, (4-Fluorophenoxy)acetic Acid, (2,4-Dichloro-5-fluorophenoxy)acetic Acid and (Indol-3-ylthio)acetic Acid
Authors: Smith G , Lynch DE , Sagatys DS , Kennard CHL , Katekar GF
Published: September 2010

The crystal structures of four analogues of the auxin herbicide series, including inactive examples, have been determined by X-ray diffraction methods. The compounds (2-isopropy1phenoxy)acetic acid (1), (4-fluorophenoxy)acetic acid (2) and (2,4-dichloro-5-fluorophenoxy)acetic acid (3) are from the phenoxyalkanoic acid series while (indol-3-ylthio)acetic acid (4) is the sulfur analogue of the natural plant hormone indole-3-acetic acid. All examples exist as hydrogen-bonded cyclic dimers [O…O, 2.640(7), 2.62(1), 2.637(4) and 2.665(4) � for (1)-(4), respectively]. Compounds (1) and (2) are essentially planar while compounds (3) and (4) have side chains anticlinally related to the ring systems, similar to (2,4-dich1orophenoxy)acetic acid and to indole-3-acetic acid.
Site of Chlorine Interaction With a Cation-Exchange Resin (Chelex-100)
Authors: Bhindi AK , Chiswell B , Rauchle GP
Published: September 2010

X-Ray photoelectron spectroscopy, 13C and 1H solution-state n.m.r., and 13C solid-state n.m.r. were used in chlorination studies on compounds, which act as models for the exchange group and the styrene divinylbenzene copolymer backbone of Chelex-100, to determine the site and mechanism of chlorine attack. Results indicate that the resin cleaves upon chlorination, and a cleavage mechanism, involving initial attack by chlorine on the exchange group imine nitrogen electron lone pairs, is proposed. The N-halo quaternary species formed loses a molecule of hydrogen chloride to give a Schiff base, which undergoes hydrolysis to an aldehyde and an ammonium salt.
The Use of Bismuth(III) Acetate in 'Wet' and 'Dry' Prevost Reactions
Authors: Trainor RW , Deacon GB , Jackson WR , Giunta N
Published: September 2010

cis -Diol and trans-diol derivatives can be prepared from alkenes by reaction with iodine and bismuth(III) acetate in 'wet' and 'dry' acetic acid, respectively. Reactions using lesser amounts of bismuth(III) acetate under 'dry' conditions give iodo acetates and under 'wet' conditions a mixture of iodohydrins and iodo ethers. Comparison of these reactions with those
promoted by silver, copper, mercury and thallium salts is included.
Betpakdalite Unmasked, and a Comment on Bond Valences
Authors: Moore PB
Published: September 2010

A new representation of the crystal structure of complex betpakdalite reported in 1984 (R ≈ 0.08) reveals a remarkable case of . hccchhccch 10-layer anion (O2-)/void ( ⁪) close-packing. The transformation matrix from earlier C12/m 1 cell to new F 2/m 11 cell is [010/100/102], new a = 11.10, b = 19.44, c = 22. 93 �, α)/10 = 2.29 Ǻ. The packing efficiency is Ve = 15.45 � α3 for 10 layers of 32(O2-+ ⁪) per layer. For Pauling r(O2-) = 1.40 �, Ve = 15.52 �3. Oxide anions populate only 46.25% of the close-packed slots; the rest are voids. The difference, Δ, between real structure and ideal (perfect) structure is (0.13 �) for O2-, (0.20 �) for cations and (0.15 A) for all atoms in the close-packed frame, range 0.00-0.43 �. The cell formula for x = 2 is H8 [K(H2O)6]4 [Ca(H20)6]8 [MO6+32 As5+8O148]28-.8H2O. It is suggested that H8 bonds with 8O(10) in the cell, the only anion bonded to only one Mo6+. The cell formula gives D(calc) = 2.90 g cm-3, close to reported D( obs ) = 2.98, 3.05; and 2.92 g cm-3. Bond strength/bond valence calculations for assorted Mp+6 � q- (M = octahedral cation linked to generalized anion �) often show extreme deviations. This is shown to be a consequence of Pauling's third rule of cation-cation repulsions across shared polyhedral edges and faces.
Rhombohedral Twin Structure in Hematite (α-Fe2O3)
Authors: Bursill LA , Peng JL , Fan XD
Published: September 2010

Electron optical imaging of the structure of haematite ( α-Fe2O3) in two projections has allowed the microscopic twinning elements of rhombohedral twins to be determined. A systematic analysis of alternative structural models, using computer-simulation and image-matching considerations, as well as crystallochemical arguments, is presented. The twin has a screw operation consisting of a pure rotation of 180� about [0111], the twinning direction, combined with a parallel translation of (1/22) [0111]. The twinning plane (0112) forms a coherent interface, consisting of face-and edge-shared octahedra , with no change in the normal nearest-neighbour coordination.
Crystal Structure and Equilibration of 1-[(1R*,4S*)-4,5,8-Trimethyl-1,2,3,4-tetrahydronaphthalen-1-yl]ethanone, C15H20O
Authors: Massywestropp RA , Massywestropp RA , Tiekink ERT , Tiekink ERT , Tippett LM , Tippett LM
Published: September 2010

The crystal structure of 1-[(1R*,4S*)-4,5,8-trimethyl-1,2,3,4-tetrahydronaphthalen-1-yl]ethan-one showed a half-chair conformation with the methyl group pseudo-axial and the acetyl group pseudo-equatorial. Equilibration gave a trans-to-cis ratio of 5:2.
Scientists as Citizens
Authors: Cornforth JW
Published: September 2010

The text is printed of a public lecture on the position of scientists in society, and the dilemmas facing scientists as a small minority possessing new information and perspectives which the majority does not yet accept or understand.
Reduction of Substituted 1-Methylene-1,2,3,4-tetrahydronaphthalene Derivatives
Authors: Tippett LM , Massywestropp RA
Published: September 2010

The stereoselectivity of reduction of 4-substituted 1-methylene-1,2,3,4-tetrahydronaphthalenes has been investigated by using catalytic hydrogenation and lithium in ammonia solutions. Serrulatane derivatives underwent highly stereoselective catalytic reduction to yield cis products. Lithium/ammonia reduction was less selective but (3R)-7,8-dimethoxyserrulat-1(20)-en-3-ol showed good selectivity to yield predominantly the cis isomer.
Synthesis With Chelated Imino Carboxylates: The Influence of Chelate Coligands on Reaction Pathways
Authors: Drok KJ , Harrowfield JM , Mcniven SJ , Sargeson AM , Skelton BW , White AH
Published: September 2010

Synthesis and X-ray crystallography have been used to explore the chemistry of chelates derived from the imines of pyruvic and phenylpyruvic acids held in a chiral environment on cobalt(III) as [Co(en)2(HNC(CH3)CO2)]2+ (en = ethane-1,2-diamine) and [Co(en)2(HNC(CH2C6H5)CO2)]2+. The latter complex was obtained by an especially facile dehydration of the corresponding β-phenylserine complex. Significant differences in both stereo- and regio-selectivity were detected in reactions of the two complexes, and, for the reaction of butenone with [Co(en)2(HNC(CH3)CO2)]2+, a pathway indetectable in previously studied reactions of the tetraammine analogue, and leading to a chelate of 4-methyl-5,6-dihydropyridine-2-carboxylate, was observed to be dominant. Kinetically determined stereospecificity was evident in the addition of ethyl cyanoacetate to [Co(en)2(HNC(CH3)CO2)]2+, whereas equilibrium control appears to exist in the stereoselective addition of nitromethane to both complexes. Crystal structure determinations on five new complexes have been used to establish these points and other important aspects of the chemical syntheses. A considerable number of new imino and amino acids can be derived through the reactions described, and the synthetic utility of both the tetraammine and bis ( ethanediamine ) complex ion systems in providing the 'free' organic products has been subjected to preliminary evaluation through the isolation of t- leucine , N-methyl-2-phenylglycine, 2-aminomethylalanine, and some vinylglycine derivatives.
Experiments Directed Towards the Synthesis of Anthracyclinones. XX. Titanium(IV)- and Tin(IV)-Mediated Cyclizations of ortho-Allyl-Substituted Homochiral Dioxans
Authors: Cambie RC , Higgs KC , Rutledge PS , Woodgate PD
Published: September 2010

Titanium(IV) chloride mediated cyclization of the ortho-methoxylated 1,3-dioxan (5) gives a high yield of a mixture (10:1) of the (7R)- tetracycles (18) and (19) which are epimeric at C9. The exclusive formation of the (7R) stereochemistry results from SN2-like attack of the olefin on a chelate involving the o- methoxy group and the dioxan ring. Ion pairing plays a major role in determining the C9 stereochemistry with internal delivery of a chloride ion giving the major product (18). The presence of a hydroxy group meta to the 1,3-dioxan as in (4) does not affect the stereoselectivity , but cyclization affords the C10 alcohol (23) as well as the C9 chloro tetracycles (16) and (17) suggesting that carbocations are involved in some cases.
Cylindricines C-G, Perhydropyrrolo[2,1-j]quinolin-7-one Alkaloids From the Ascidian Clavelina cylindrica
Authors: Li CP , Blackman AJ
Published: September 2010

Five novel perhydropyrrolo [2,1-j]quinolin-7-one alkaloids have been isolated from two different Tasmanian collections of the ascidian Clavelina cylindrica. The compounds, cylindricines C-G, are closely related in structure to cylindricine A which has been obtained previously from the same ascidian. Cylindricines F and G are thiocyanates, the first known from an ascidian . The identification of the new alkaloids was by 1H n.m.r. and 13C n.m.r. spectroscopy, high-resolution e.i . mass spectrometry, and chemical interconversions.
The Origin of the Unusual C4ν Structure Predicted for SH4
Authors: Marsden CJ , Smart BA
Published: September 2010

Ab initio molecular orbital calculations have been performed on C2v and C4v isomers of SH4, SF4 and S(CH3)4 to investigate the origin of the different structures adopted by these molecules. We propose an electrostatic model similar in spirit to the VSEPR approach; this implies that the net charges on the ligands L in SL4 compounds can control the geometry of these compounds. Steric factors may also be significant. Even though the net charges on hydrogen and on the CH3 group are similar when these act as ligands towards sulfur, the carbon atom in the methyl group bears a substantial negative net charge, which has important structural consequences. Binding energies and structural parameters are presented for SH4 which are obtained from more complete theoretical calculations than those previously reported.
Neural inhibition enables selection during language processing
Authors: Snyder Hannah R. , Hutchison Natalie , Nyhus Erika , Curran Tim , Banich Marie T. , O'Reilly Randall C. , Munakata Yuko
Published: September 2010

Whether grocery shopping or choosing words to express a thought, selecting between options can be challenging, especially for people with anxiety. We investigate the neural mechanisms supporting selection during language processing and its breakdown in anxiety. Our neural network simulations demonstrate a critical role for competitive, inhibitory dynamics supported by GABAergic interneurons. As predicted by our model, we find that anxiety (associated with reduced neural inhibition) impairs selection among options and associated prefrontal cortical activity, even in a simple, nonaffective verb-generation task, and the GABA agonist midazolam (which increases neural inhibition) improves selection, whereas retrieval from semantic memory is unaffected when selection demands are low. Neural inhibition is key to choosing our words.
Inflammatory Mediators of Esophagitis Alter p27Kip1 Expression in Esophageal Epithelial Cells
Authors: Nguyen Kim‐Doan Katrina , Blain Stacy W , Gress Frank , Treem William R
Published: September 2010

Background:

Barrett esophagus (BE) is a premalignant condition that develops due to prolonged gastroesophageal reflux disease (GERD). In some but not all cases, BE progresses to Barrett‐associated adenocarcinoma. p27Kip1is a tumor‐suppressor protein that regulates the cell's division cycle and appears to be frequently inactivated in Barrett‐associated adenocarcinoma due to increased degradation or cytoplasmic mislocalization. Reduced or mislocalized p27 would remove it from its nuclear targets and result in increased proliferation. Although bile acid and hydrochloric acid (HCl) are linked to the pathogenesis of BE, not every patient with BE has a history of GERD. Eosinophilic esophagitis mimics GERD, but eosinophil granule proteins, known to mediate inflammation, have not been linked to BE. It was unknown whether mediators of esophagitis affect p27 expression and/or localization in normal esophageal cells. We assessed the effects of bile acid, HCl, and eosinophil granule proteins on p27 protein expression, localization, and its ability to regulate cell proliferation.

Materials and Methods:

Human esophageal epithelial (HET‐1A) cells were incubated with chenodeoxycholic acid (CDC), HCl, and eosinophil granule proteins (major basic protein, MBP; and eosinophil peroxidase, EPO). Cell viability analysis, immunoblot, immunofluorescence microscopy, and flow cytometric analysis were performed.

Results:

Exposure of HET‐1A cells to CDC, HCl, MBP, and EPO did not affect total p27 levels. CDC, HCl, MBP, and EPO caused mislocalization of p27 from the nucleus to the cytoplasm. Flow cytometry showed that CDC exposure also increased HET‐1A cell proliferation.

Conclusions:

Mislocalization of p27 caused by mediators of GERD or eosinophilic esophagitis may serve as an early marker of increased cell proliferation, which may contribute to the risk for esophageal dysplasia.
Cytokeratin 8 interacts with clumping factor B: a new possible virulence factor target
Authors: Haim M. , Trost A. , Maier C. J. , Achatz G. , Feichtner S. , Hintner H. , Bauer J. W. , önder K.
Published: September 2010

Staphylococcus aureusis a human pathogen of growing clinical significance, owing to its increasing levels of resistance to most antibiotics. Infections range from mild wound infections to severe infections such as endocarditis, osteomyelitis and septic shock. Adherence ofS. aureusto human host cells is an important step, leading to colonization and infection. Adherence is mediated by a multiplicity of proteins expressed on the bacterial surface, including clumping factor B. In this study, we aimed to identify new targets of clumping factor B in human keratinocytes by undertaking a genome-wide yeast two-hybrid screen of a human keratinocyte cDNA library. We show that clumping factor B is capable of binding cytokeratin 8 (CK8), a type II cytokeratin. Using a domain-mapping strategy we identified amino acids 437–464 as necessary for this interaction. Recombinantly expressed fragments of both proteins were used in pull-down experiments and confirmed the yeast two-hybrid studies. Analysis withS. aureusstrain Newman deficient in clumping factor B showed the clumping factor B-dependence of the interaction with CK8. We postulate that the clumping factor B–CK8 interaction is a novel factor inS. aureusinfections.
Variation in the Neisseria meningitidis FadL-like protein: an evolutionary model for a relatively low-abundance surface antigen
Authors: Yero Daniel , Vipond Caroline , Climent Yanet , Sardiñas Gretel , Feavers Ian M. , Pajón Rolando
Published: September 2010

The molecular diversity of a novelNeisseria meningitidisantigen, encoded by the ORF NMB0088 of MC58 (FadL-like protein), was assessed in a panel of 64 diverse meningococcal strains. The panel consisted of strains belonging to different serogroups, serotypes, serosubtypes and MLST sequence types, of different clinical sources, years and countries of isolation. Based on the sequence variability of the protein, the FadL-like protein has been divided into four variant groups in this species. Antigen variants were associated with specific serogroups and MLST clonal complexes. Maximum-likelihood analyses were used to determine the relationships among sequences and to compare the selection pressures acting on the encoded protein. Furthermore, a model of population genetics and molecular evolution was used to detect natural selection in DNA sequences using the non-synonymous : synonymous substitution (dN : dS) ratio. The meningococcal sequences were also compared with those of the related surface protein in non-pathogenic commensalNeisseriaspecies to investigate potential horizontal gene transfer. TheN. meningitidis fadLgene was subject to only weak positive selection pressure and was less diverse than meningococcal major outer-membrane proteins. The majority of the variability infadLwas due to recombination among existing alleles from the same or related species that resulted in a discrete mosaic structure in the meningococcal population. In general, the population structuring observed based on the FadL-like membrane protein indicates that it is under intermediate immune selection. However, the emergence of a new subvariant within the hyperinvasive lineages demonstrates the phenotypic adaptability ofN. meningitidis, probably in response to selective pressure.
Wine producers' strategic response to a crisis situation
Authors: Duquesnois Franck , Gurãu Cãlin , Le Roy Frédéric
Published: September 2010

Purpose

The purpose of this paper is to investigate the competitive strategies adopted by French wine producing firms in a crisis context.

Design/methodology/approach

First, two case studies have been developed through interviews with wine producers. They show that many strategies, corresponding to different levels of performance, are possible in a crisis industry. Second, an empirical study has been conducted applying a questionnaire survey addressed in June 2008 to wine producing firms from the Languedoc‐Roussillon region, south of France. Third, ordinal regression is operated in order to link financial performance and strategic choices of the investigated 160 respondent firms.

Findings

The findings indicated some interesting trends concerning wine producers' perception regarding the effect of the crisis and the strategies adopted by firms. The preferred strategic choice of the majority of investigated firms is the combination of “niche + differentiation” strategies. On the other hand, the strategic choice of firms is influenced by their experience; many less experienced firms prefer to adopt a differentiation strategy or a combination of the “niche + differentiation” strategies. Moreover, statistical analysis shows that no implementation of niche, differentiation or relational marketing lead toward decreasing turnover.

Research limitations/implications

This research is focused only on wine producing firms from Languedoc‐Roussillon region in France. A second limitation is the fact that firms' performance was not systematically measured. The performance is evaluated mainly indirectly, considering that the investigated firms have survived the crisis.

Originality/value

Very few studies have been conducted on this particular topic.
Sports events and tourism: the Singapore Formula One Grand Prix
Authors: Henderson Joan C. , Foo Ken , Lim Hermes , Yip Serene
Published: September 2010

Purpose

The purpose of this paper is to examine the significance of the inaugural Singapore Formula One Grand Prix within a tourism context. Impacts of the event and attitudes towards it are explored with a view to illuminating the consequences of and challenges inherent in sports events tourism for destinations with limited prior experience.

Design/methodology/approach

A case study approach is employed and the account is based upon the collection and analysis of materials in the public domain. This information is supplemented by primary data obtained from a survey of local residents and personal observation.

Findings

The Singapore Grand Prix is an example of sports events tourism, a subset of events tourism, which now has an important role in development and marketing strategies. Official expectations of the particular event seem to have been largely met, but understanding of its costs and benefits varies and whether the latter outweighs the former remains to be determined. Lessons have been learned from the experience, but the dynamic environment of tourism means constant change and new dilemmas to confront.

Originality/value

The use of sports events in tourism strategies is a comparatively recent trend in parts of Asia and the case of Singapore reveals some of the underlying factors and forces at work. Insights are afforded into impacts of major sports contests at such destinations and the obstacles to overcome in pursuit of success.
Diagnosis of adrenal histoplasmosis by fine needle aspiration cytology: an analysis based on five cases
Authors: Jaiswal S. , Vij M. , Chand G. , Misra R. , Pandey R.
Published: September 2010

S. Jaiswal, M. Vij, G. Chand, R. Misra and R. Pandey Diagnosis of adrenal histoplasmosis by fine needle aspiration cytology: an analysis based on five cases

Background: There is limited description in the literature of the initial diagnosis of adrenal histoplasmosis by fine needle aspiration cytology (FNAC).

Objective: To study the aetiology, clinical features and morphological differential diagnosis of adrenal histoplasmosis diagnosed initially by FNAC.

Methods: Five cases diagnosed by ultrasound‐guided FNAC from 2008 to 2010 were found in the laboratory records and reviewed. Clinical features and cytomorphological features were correlated.

Results: All the patients were male and were aged 45–83 years (mean 60 years). Three patients had a history of contact with birds, one was diabetic and all were negative for human immunodeficiency virus (HIV). The commonest symptom was weight loss. On cytological smears, uniform round to oval (about 2–4 μm in diameter) budding yeasts were seen intracellularly (within histiocytes) as well as extracellularly. In three cases, an inflammatory response in the form of epithelioid cell granulomas along with multinucleated giant cells was seen.

Conclusions: Adrenal histoplasmosis does occur in immunocompetent persons living in areas not endemic for the disease. Although it is not common, it needs to be considered in the differential diagnosis of bilateral adrenal enlargement. FNAC is a simple, safe technique to establish the initial diagnosis. Correct diagnosis and treatment leads to a favourable outcome.
Depression among female psychiatric nurses in southern Taiwan: main and moderating effects of job stress, coping behaviour and social support
Authors: Lin Huey‐S , Probst Janice C , Hsu Yu‐C
Published: September 2010

Aims and objectives.  In this study, we tested the following hypotheses among psychiatric nurses: (1) job stress would be positively correlated with depression; (2) coping behaviour would be significantly correlated with depression and moderate the relationship between job stress and depression; (3) social support would be significantly negatively correlated with depression and was a significant moderator on the relationship between job stress and depression.

Background.  Most studies in Taiwan related to depression have focused on the general public rather than nurses. The main effect of job stress (coping behaviour, social support) on level of depression has been documented in some population, but the moderating effects of coping behaviours and social support on the relationship between job stress and depression have not been well studied among nurses, especially among psychiatric nurses.

Design.  A cross‐sectional research design was employed.

Method.  A self‐report questionnaire was adopted to measure personal characteristics, depression (Beck Depression Inventory), job stress (Taiwanese Nurse Stress Checklist), coping behaviour (Jalowiec Coping Scale) and social support (short form, Interpersonal Support Evaluation List). Eligible subjects were female, non‐supervisory, inpatient ward nurses in a psychiatric hospital in southern Taiwan. One hundred and fifty‐four questionnaires were distributed, and the response rate was 91·6%.

Results.  After adjusting for covariates, we found that: (1) Job stress and affective‐oriented coping were significantly positively correlated with BDI‐II scores. (2) Coping behaviour was not a significant moderator on the relationship between job stress and depression scores among psychiatric nurses, but social support was.

Conclusions.  Depression scores were correlated with job stress and affective‐oriented coping, but social support could work to reduce the effect of stress on depression among psychiatric nurses.

Relevance to clinical practice.  Nursing managers should explore both ways of reducing job stress and techniques for building social support networks in the institution to protect their members against stress and depression.
The use of sildenafil to treat pulmonary hypertension associated with interstitial lung disease
Authors: CORTE Tamera J. , GATZOULIS Michael A. , PARFITT Lisa , HARRIES Carl , WELLS Athol U. , WORT S. John
Published: September 2010

Background and objective:  Limited data suggest a benefit following sildenafil treatment in patients with pulmonary hypertension (PH) and interstitial lung disease (ILD). The role of sildenafil in the management of PH in ILD is not clear. We report our experience of ILD patients with PH after 6‐month sildenafil therapy.

Methods:  We reviewed 15 patients (mean age 55 ± 15 years; 8 men) with ILD (mean FVC 52.6 ± 15.4%) and PH (mean right ventricular systolic pressure 73.8 ± 17.8 mm Hg). Median brain natriuretic peptide: 37 (5–452) pmol/L; mean 6MWD: 156 ± 101 m.

Results:  Following 6‐month treatment with sildenafil, brain natriuretic peptide levels were lower (n = 12, P = 0.03), 6MWD was higher (n = 6, P < 0.05), but no change in right ventricular systolic pressure (n = 11) was demonstrated.

Conclusions:  Our observations suggest that sildenafil may be useful in the management of PH in ILD. Controlled trials are warranted before therapeutic recommendations can be made.