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Single‐crystal X‐ray diffraction studies for a variety of metal ion complexes of functionalised sarcophagines (sarcophagine=sar=3,6,10,13,16,19‐hexa‐azabicyclo[6.6.6]icosane) have further confirmed not only that the form of the metal ion/sar unit is unique for each metal, albeit with a sensitivity of the conformation to the associated counter anions, but also that for any given metal and ligand substituent, the dimensions (bond lengths and angles) of the complex and the substituent at the secondary nitrogen centres do not differ significantly from those of the isolated components. Despite this, where the substituent contains reactive sites, the reactivity differs markedly from that of their form in an uncoordinated substrate. Rationalisations are offered for these differences, in part through the use of Hirshfeld surface analysis of the intermolecular interactions. The kinetic inertness of the complexes means that the metal ions can be considered to act as regioselective protecting groups. [ABSTRACT FROM AUTHOR]

Reactions of [Ru{C=C(H)‐1,4‐C6H4C≡CH}(PPh3)2Cp]BF4 ([1 a]BF4) with hydrohalic acids, HX, results in the formation of [Ru{C≡C‐1,4‐C6H4‐C(X)=CH2}(PPh3)2Cp] [X=Cl (2 a‐Cl), Br (2 a‐Br)], arising from facile Markovnikov addition of halide anions to the putative quinoidal cumulene cation [Ru(=C=C=C6H4=C=CH2)(PPh3)2Cp]+. Similarly, [M{C=C(H)‐1,4‐C6H4‐C≡CH}(LL)Cp ]BF4 [M(LL)Cp'=Ru(PPh3)2Cp ([1 a]BF4); Ru(dppe)Cp* ([1 b]BF4); Fe(dppe)Cp ([1 c]BF4); Fe(dppe)Cp* ([1 d]BF4)] react with H+/H2O to give the acyl‐functionalised phenylacetylide complexes [M{C≡C‐1,4‐C6H4‐C(=O)CH3}(LL)Cp'] (3 a–d) after workup. The Markovnikov addition of the nucleophile to the remote alkyne in the cations [1 a–d]+ is difficult to rationalise from the vinylidene form of the precursor and is much more satisfactorily explained from initial isomerisation to the quinoidal cumulene complexes [M(=C=C=C6H4=C=CH2)(LL)Cp']+ prior to attack at the more exposed, remote quaternary carbon. Thus, whilst representative acetylide complexes [Ru(C≡C‐1,4‐C6H4‐C≡CH)(PPh3)2Cp] (4 a) and [Ru(C≡C‐1,4‐C6H4‐C≡CH)(dppe)Cp*] (4 b) reacted with the relatively small electrophiles [CN]+ and [C7H7]+ at the β‐carbon to give the expected vinylidene complexes, the bulky trityl ([CPh3]+) electrophile reacted with [M(C≡C‐1,4‐C6H4‐C≡CH)(LL)Cp'] [M(LL)Cp'=Ru(PPh3)2Cp (4 a); Ru(dppe)Cp* (4 b); Fe(dppe)Cp (4 c); Fe(dppe)Cp* (4 d)] at the more exposed remote end of the carbon‐rich ligand to give the putative quinoidal cumulene complexes [M{C=C=C6H4=C=C(H)CPh3}(LL)Cp']+, which were isolated as the water adducts [M{C≡C‐1,4‐C6H4‐C(=O)CH2CPh3}(LL)Cp'] (6 a–d). Evincing the scope of the formation of such extended cumulenes from ethynyl‐substituted arylvinylene precursors, the rather reactive half‐sandwich (5‐ethynyl‐2‐thienyl)vinylidene complexes [M{C=C(H)‐2,5‐cC4H2S‐C≡CH}(LL)Cp']BF4 ([7 a–d]BF4 add water readily to give [M{C≡C‐2,5‐cC4H2S‐C(=O)CH3}(LL)Cp'] (8 a–d)]. [ABSTRACT FROM AUTHOR]

Ten manganese(I) tricarbonyl diimine complexes bound to variably functionalised 5‐aryl‐tetrazolato ligands were prepared, and their photochemical properties were investigated. Upon exposure to light at 365 nm, each complex decomposed to its free diimine and tetrazolato ligands, simultaneously dissociating three CO ligands, as evidenced by changes in the IR spectra of the irradiated complexes over time. The anti‐bacterial properties of one of these complexes were tested against Escherichia coli. While the complex displayed no effect on the bacterial growth in the dark, pre‐irradiated solutions inhibited bacterial growth. Comparative studies revealed that the antibacterial properties originate from the presence of free 1,10‐phenanthroline. [ABSTRACT FROM AUTHOR]

Bioactive natural products underpin the intriguing pollination strategy used by sexually deceptive orchids. These compounds, which mimic the sex pheromones of the female insect, are emitted in particular blends to lure male insect pollinators of specific species. By combining methods from field biology, analytical chemistry, electrophysiology, crystallography, and organic synthesis, we report that an undescribed β‐hydroxylactone, in combination with two specific hydroxymethylpyrazines, act as pollinator attractants in the rare hammer orchid Drakaea micrantha. This discovery represents an unusual case of chemically unrelated compounds being used together as a sexual attractant. Furthermore, this is the first example of the identification of pollinator attractants in an endangered orchid, enabling the use of chemistry in orchid conservation. Our synthetic blend is now available to be used in pollinator surveys to locate suitable sites for plant conservation translocations. [ABSTRACT FROM AUTHOR]

Together with the more intuitive and commonly recognized conductance mechanisms of charge‐hopping and tunneling, quantum‐interference (QI) phenomena have been identified as important factors affecting charge transport through molecules. Consequently, establishing simple and flexible molecular‐design strategies to understand, control, and exploit QI in molecular junctions poses an exciting challenge. Here we demonstrate that destructive quantum interference (DQI) in meta‐substituted phenylene ethylene‐type oligomers (m‐OPE) can be tuned by changing the position and conformation of methoxy (OMe) substituents at the central phenylene ring. These substituents play the role of molecular‐scale taps, which can be switched on or off to control the current flow through a molecule. Our experimental results conclusively verify recently postulated magic‐ratio and orbital‐product rules, and highlight a novel chemical design strategy for tuning and gating DQI features to create single‐molecule devices with desirable electronic functions. [ABSTRACT FROM AUTHOR]

The observation of an unusual crystal habit in the common diuretic drug hydrochlorothiazide (HCT), and identification of its subtle conformational chirality, has stimulated a detailed investigation of its crystalline forms. Enantiomeric conformers of HCT resolve into an unusual structure of conjoined enantiomorphic twin crystals comprising enantiopure domains of opposite chirality. The purity of the domains and the chiral molecular conformation are confirmed by spatially revolved synchrotron micro‐XRD experiments and neutron diffraction, respectively. Macroscopic inversion twin symmetry observed between the crystal wings suggests a pseudoracemic structure that is not a solid solution or a layered crystal structure, but an unusual structural variant of conglomerates and racemic twins. Computed interaction energies for molecular pairs in the racemic and enantiopure polymorphs of HCT, and the observation of large opposing unit‐cell dipole moments for the enantiopure domains in these twin crystals, suggest a plausible crystal nucleation mechanism for this unusual crystal habit. [ABSTRACT FROM AUTHOR]

Class II mixed‐valence bimetallic complexes {[Cp′(PP)M]C≡C−C≡N[M′(PP)′Cp′]}2+ (M, M′=Ru, Fe; PP=dppe, (PPh3)2; Cp′=Cp*, Cp) exist as conformational ensembles in fluid solution, with a population of structures ranging from cis‐ to trans‐like geometries. Each conformer gives rise to its own series of low‐energy intervalence charge‐transfer (IVCT) and local d–d transitions, which overlap in the NIR region, giving complex band envelopes in the NIR absorption spectrum, which prevent any meaningful attempt at analysis of the band shape. However, DFT and time‐dependent (TD)DFT calculations with dispersion‐corrected global‐hybrid (BLYP35‐D3) or local hybrid (lh‐SsirPW92‐D3) functionals on a small number of optimised structures chosen to sample the ground state potential energy hypersurfaces of each of these complexes has proven sufficient to explain the major features of the electronic spectra. Although modest in terms of computational expense, this approach provides a more accurate description of the underlying molecular electronic structure than would be possible through analysis of the IVCT band by using the static point‐charge model of Marcus–Hush theory and derivatives, or TDDFT calculations from a single (global) minimum energy geometry. [ABSTRACT FROM AUTHOR]

The synthesis, characterization and use, as initiators for phenylacetylene polymerizations, of three new rhodium(I)‐vinyl complexes containing fluorenyl functionality with fluorine‐functionalized phosphine ligands is described. Rh(nbd)(CPh=CFlu)P(4‐FC6H4)3, Rh(nbd)(CPh=CFlu)P(4‐CF3C6H4)3, and Rh(nbd)(CPh=CFlu)P[3,5‐(CF3)2C6H3]3 (nbd: 2,5‐norbornadiene; Flu: fluorenyl) were prepared and isolated as discrete, orange compounds and were readily recrystallized yielding X‐ray quality crystals. All complexes were characterized by a combination of 1H, 31P, 19F, 103Rh NMR spectroscopy and 2D 31P‐103Rh/31P‐103Rh{103Rh} heteronuclear multiple‐quantum correlation (HMQC) experiments, elemental analysis, and single‐crystal X‐ray analysis. The complexes were active as initiators in the co‐ordination insertion polymerization of phenylacetylene, with initiation efficiencies spanning the range 13–56 %, and yielded polyphenylacetylenes of low dispersity (Ð = Mw/Mn) with high cis‐transoidal stereoregularity. Three new well‐defined, isolated rhodium(I) vinyl complexes containing fluorenyl functionality in combination with fluorine functionalized phosphine ligands are presented. All complexes are shown to be active as initiators for phenylacetylene yielding highly stereoregular polymers with a cis‐transoidal structure. [ABSTRACT FROM AUTHOR]

The formal cycloaddition adduct of 1,4-benzoquinone with two equivalents of cyclopentadiene is a scaffold with two non-conjugated alkenes. Both alkenes undergo endo [4+2] cycloaddition with a diene to form a rigid U-shaped molecular cleft. Here we show experimental, computational and structural evidence that π interactions between the alkenes affect structural rigidity, Diels-Alder reactivity, cleft formation and host-guest capture. [ABSTRACT FROM AUTHOR]

The trans-epoxysuccinyl amide group as a biologically active moiety in cysteine protease inhibitors such as loxistatin acid E64c has been used as a benchmark system for theoretical studies of environmental effects on the electron density of small active ingredients in relation to their biological activity. Here, the synthesis and the electronic properties of the smallest possible active site model compound are reported to close the gap between the unknown experimental electron density of trans-epoxysuccinyl amides and the well-known function of related drugs. Intramolecular substituent effects are separated from intermolecular crystal packing effects on the electron density, which allows us to predict the conditions under which an experimental electron density investigation on trans-epoxysuccinyl amides will be possible. In this context, the special importance of the carboxylic acid function in the model compound for both crystal packing and biological activity is revealed through the novel tool of model energy analysis. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of 5,11,17,23-tetra- tert-butyl-25-hydroxy-26,27,28-tris(tetrazol-5-ylmethoxy)calix[4]arene is reported. Purification of the macrocycle required the use of preparative HPLC techniques. The macrocycle was found to be a poorer ligand for complexation of lanthanoid cations than the bis(tetrazole) analogue, but somewhat more effective than the tetrakis(tetrazole)-substituted derivative. Two metal complexes of the tris(tetrazole)-calixarene were structurally characterised. A polymeric sodium salt of the tris(tetrazole)-calixarene was isolated from a solution containing yttrium and a sodium acetate buffer. A praseodymium complex was isolated in the presence of an ammonium acetate buffer, where the calixarene acts as a unidentate ligand, bound to the metal atom through one tetrazole N-atom. Increasing the amount of buffer resulted in the crystallisation of a metal-free ammonium salt of the calixarene. [ABSTRACT FROM AUTHOR]

The reaction of hydrated lanthanoid chlorides with tribenzoylmethane and an alkali metal hydroxide consistently resulted in the crystallization of neutral tetranuclear assemblies with the general formula [Ln(Ae ⋅HOEt)( L)4]2 (Ln=Eu3+, Er3+, Yb3+; Ae=Na+, K+, Rb+). Analysis of the crystal structures of these species revealed a coordination geometry that varied from a slightly distorted square antiprism to a slightly distorted triangular dodecahedron, with the specific geometrical shape being dependent on the degree of lattice solvation and identity of the alkali metal. The near-infrared (NIR)-emitting assemblies of Yb3+ and Er3+ showed remarkably efficient emission, characterized by significantly longer excited-state lifetimes ( τobs≈37-47 μs for Yb3+ and τobs≈4-6 μs for Er3+) when compared with the broader family of lanthanoid β-diketonate species, even in the case of perfluorination of the ligands. The Eu3+ assemblies show bright red emission and a luminescence performance ( τobs≈0.5 ms, ${{\Phi}{{{\rm L}\hfill \atop {\rm Ln}\hfill}}}$≈35-37 %, ηsens≈68-70 %) more akin to the β-diketonate species. The results highlight that the β-triketonate ligand offers a tunable and facile system for the preparation of efficient NIR emitters without the need for more complicated perfluorination or deuteration synthetic strategies. [ABSTRACT FROM AUTHOR]

Copper(I) thiocyanate derivatives were prepared by the reaction of CuNCS with pyridine (py) and tertiary monophosphine ligands [PR3 in general; in detail: PPh3, triphenylphosphine, P(4-FPh)3, tris(4-fluorophenyl)phosphine)], as well as the potentially bidentate ligand diphenyl(2-pyridyl)phosphine (PPh2py). Mechanochemical methods were used in some cases to investigate stoichieometries that were not easily accessible by conventional solution syntheses. Three forms of the resulting adducts of CuNCS/PR3/py-base (1:3- n: n) stoichiometry-all containing four-coordinate copper(I) atoms and monodentate N-thiocyanate groups-were confirmed crystallographically. Mononuclear arrays are defined for [(PPh2py)3- n(py) nCu NCS], n = 0, 1, 2, the monodentate thiocyanate being N-coordinated in all; two polymorphs are observed for the n = 2 complex, both crystallizing in monoclinic P21 ( Z = 2) cells with similar cell dimensions, but with aromatic components eclipsed about the Cu-P bond in the PPh3 complex, and staggered in the PPh2py complex. Bridging thiocyanate groups are found in the 1:1:1 CuNCS/PPh2py/2-methylpyridine (mpy) and P(4-FPh)3/mpy complexes, wherein centrosymmetric dimers with eight-membered central rings are obtained: [(R3P)(mpy)Cu( NC S)2Cu(PR3)(mpy)], as is also the case in the parent 1:2 CuNCS/PPh2py adduct [(pyPh2P)2Cu( NC S)2Cu(PPh2py)2]. For the 1:1:1 Cu NC S/P(4-FPh)3/py and PPh3/Brmpy (Brmpy = 3-bromo-4-methylpyridine) adducts, and, likely, Cu NC S/PPh2py/py (1:1:1), single-stranded polymers of the form [ ···Cu( NC S)(PR3)(py-base)(Cu) ···](∞|∞) with linearly bridging NCS ligands were obtained. Some derivatives, representative of all forms, display medium to strong green to blue luminescence when excited with radiation at 365 nm. The 31P CPMAS NMR spectroscopic data clearly differentiate the inequivalent phosphorus positions within each system, showing a wide range of 1 J(31P,63/65Cu) values ranging from 965 Hz for [Cu( NCS)(PPh2py)3] to 1540 Hz for dimeric [(4-FPh)3P(mpy)Cu( NC S)2Cu(P(4-FPh)3)(mpy)], reflecting the large variations in the Cu-P bond length. [ABSTRACT FROM AUTHOR]

Herein we describe the design and preparation of inexpensive, air-stable nickel phosphite-based catalysts for use in the CN cross-coupling reaction. The combination of nickel tetrakis(triphenyl phosphite) {Ni[P(OPh)3]4} and 1,1′-bis(diphenylphosphino)ferrocene (dppf), and in particular a newly developed catalyst (dppf)Ni[P(OPh)3]2, were found to be extremely effective in catalyzing a range of amination reactions of anilines and amines with aryl chlorides. This new catalyst system offers an alternative to the bis(cyclooctadienyl)nickel [Ni(COD)2] and palladium(0) catalysts commonly used for CN bond formation. [ABSTRACT FROM AUTHOR]

[RuCl(arene)(μ-Cl)]2 dimers were treated in a 1:2 molar ratio with sodium or thallium salts of bis- and tris(pyrazolyl)borate ligands [Na(Bp [ABSTRACT FROM AUTHOR]

A quaterphenylterpyridine ligand (qptpy) with the rodlike quaterphenyl unit attached in the 4′-position has been synthesised by a Pd-catalysed Suzuki cross-coupling reaction. A crystal structure determination on the complex [Zn(qptpy)Cl2]·dmf (dmf = dimethylformamide) has shown the ligand to be bound in the expected N3-tridentate manner to the essentially trigonal-bipyramidal dichloro metal ion, with the quaterphenyl substituents involving a twisted array of the separate phenyl groups and the shortest contacts between aromatic groups involving just the polar terpyridine head groups to give an infinite, offset face-to-face (OFF) π-stacking array. A comparison is made with the structures of the bis(ligand) complexes of Zn(ClO4)2 and Cd(ClO4)2 with the bromobiphenylterpyridine ligand (Brbptpy) synthesised as an intermediate for the formation of qptpy. A study of the absorption and emission spectra of qptpy and a range of its metal-ion complexes has shown that the ligand provides a ratiometric fluorescence response for both ZnII and CdII. [ABSTRACT FROM AUTHOR]

The single-crystal structure of a β'-copper vanadium bronze, Cu0.63V2O5, has been studied at room temperature and 9.6 K, and compared with that of the β-sodium vanadium bronze, Na0.33V2O5, structure. No convincing evidence to oppose an assignment of centrosymmetric C2/m symmetry to the structure was identified using the X-ray data. A subsequent convergent beam electron diffraction (CBED) experiment was performed and confirmed the C2/m space group. The oxygen-vanadium atom framework of Cu0.63V2O5 iS close to that of Na0.33V2O5. However, in the copper compound the Cu atoms are located in two positions: Cul in the 4(i) position with x = 0.541, y = 0 and z: 0.345, and Cu2 in the 8(j) position with x = 0.529, y = 0.038 and z: 0.357. The crystal structure changes little with temperature. Disorder of the Cu ion over two sites is seen at 9.6 K. This suggests that distribution of the Cu atoms over two sites is of a more static than dynamic nature. [ABSTRACT FROM AUTHOR]

A single crystal of 3,5-di-tert-butylpyrazole has been the subject of structure determinations at 10, 100, 120 and 299 K. Above ∼ 110 K, the structure is Pbca, a ≈ 11.3, b ≈ 20.6, c ≈ 10 Å, Z = 8. Below 110 K, the c axis is doubled and the space group becomes Pb21a, Z = 16. Here the asymmetric unit is comprised of four molecules, arranged as a pair of overlapping hydrogen-bonded dimers, all components being ordered. In each case one methyl group of each t-butyl group lies coplanar with its parent pyrazole ring and, within each quasi-inversion-related dimer, one molecule has both of these methyl groups directed away from the N2 component ‘cis’, while in the other, one methyl group is toward (‘trans’). Above 110 K the four molecules collapse into one, with one t-butyl group (corresponding to an overlaid ‘cis/trans’ pair of the low-temperature form) modelled as disordered. The disorder has been previously described as ‘temperature dependent’ (Deacon et al, 2001), but the present studies suggest it to be dependent on the history of the particular specimen as well. [ABSTRACT FROM AUTHOR]

The crystal structures of the α-alums rubidium chromium bis(­sulfate) dodecahydrate, RbCr(SO4)2·12H2O, and caesium chromium bis[tetraoxoselenate(VI)] dodecahydrate, CsCr(SeO4)2·12H2O, have been determined by X-ray diffraction at 293 and 12 K. The metal atoms lie on sites and the anions lie on threefold rotation axes. The accurate and extensive data sets lead to much more precise determinations than are available from earlier work, particularly at 12 K. The changes in the atomic displacement parameters between 293 and 12 K correspond to the respective predominances of intermolecular and intramolecular vibrational effects. [ABSTRACT FROM AUTHOR]

The crystal structures of the Tutton salts (NH4)2-[Cu(H2O)6(SO4)2, diammonium hexaaquacopper disulfate, formed with normal water and isotopically substituted H218O, have been determined by X-ray diffraction at 9.5 K and are very similar, with Cu-O(7) the longest of the Cu-O bonds of the Jahn-Teller distorted octahedral [Cu(H2O) 6]2+ complex. It is known that structural differences accompany deuteration of (NH4)2[Cu(H2O) 6](SO4)2, the most dramatic of which is a switch to Cu-O(8) as the longest such bond. The present result suggest that the structural differences are associated with hydrogen-bonding effects rather than with increased mass of the water ligands affecting the Jahn-Teller coupling. The Jahn-Teller distortions and hydrogen-bonding contacts in the compounds are compared with those reported for other Tutton salts at ambient and high pressure. [ABSTRACT FROM AUTHOR]

Keywords: alkynes; cumulenes; electrophiles; metal acetylides; ruthenium EN alkynes cumulenes electrophiles metal acetylides ruthenium 7143 7143 1 06/08/20 20200605 NES 200605 B The formation of "quinoidal cumulenes" b is inferred from a series of trapping reactions using ruthenium and iron vinylidene and alkynyl precursors with a variety of nucleophilic and electrophilic species. This is illustrated in the cover artwork (designed by Brady Johnston) by the transformation of a ruthenium vinylidene complex, wherein the terminal alkyne moiety reacts with water to give a corresponding acetyl group. Alkynes, cumulenes, electrophiles, metal acetylides, ruthenium. [Extracted from the article]

The crystal structure of the title compound, [ReCl4(C8H10N2)2], has been determined by X-ray diffraction at 11 K and by neutron diffraction at 20 K. The accurate and extensive data sets lead to more precise determinations than are available from earlier work. The agreement in atomic positional and displacement parameters at these very low temperatures is good. The results will facilitate re-examination of the magnetic structure of the complex. The Re atom lies on a special position and the molecule has twofold crystallographic symmetry. [ABSTRACT FROM AUTHOR]

Precise X-ray determinations of the crystal structure of the 1:2 complex of N-ethyl- N-methyl­morpholinium and 7,7,8,8-tetra­cyano- p-quinodi­methanide, abbreviated as MEM-TCNQ or MEM(TCNQ)2 (C7H16NO+·2C12H4N40.5−), have been performed at 293 and at 10 K. Evidence for the expected spin-Peierls transition at 19 K is not found, and this may follow from radiation damage to the crystal or from insufficient equipment sensitivity. [ABSTRACT FROM AUTHOR]

The crystal structure of Na2Fe(CN)5(NO)·2D2O, disodium penta­cyano­nitro­syl­ferrate(III) bis­(dideuterium oxide), has been determined by X-ray diffraction at 11 and 293 K, and by neutron diffraction at 15 K. The accurate and extensive data sets lead to more precise determinations than are available from earlier work. The agreement in atomic positional and displacement parameters between the determinations at low temperature is very good. [ABSTRACT FROM AUTHOR]

The crystal structure of dicaesium potassium hexacyanomanganese(III) has been determined by X-ray diffraction at 293, 85 and 10 K. The Mn and K atoms lie on inversion centres and the Cs atom is in a general position. The accurate and extensive data sets collected should be suitable for charge-density analysis studies. [ABSTRACT FROM AUTHOR]

The crystal structure of hexa­carbonyl­chromium(0), [Cr(CO)6], has been refined with an accurate and extensive X-ray data set collected at 11 K. This data set should be suitable for charge-density analysis studies. The structure is made up of isolated Cr(CO)6 mol­ecules of very near octahedral symmetry, containing a crystallographic mirror plane. [ABSTRACT FROM AUTHOR]

The crystal structure of trisodium hexanitro­cobaltate(III) has been determined by X-ray diffraction at 293 and 10 K. It contains the slightly distorted octahedral Co(NO2)63− anion. [ABSTRACT FROM AUTHOR]

The title compound, (NH4)ZnPO4-HEX, is built up from a three-dimensional network of ZnO4 and PO4 tetrahedra [ dav(Zn-O) = 1.9400 (7) Å and dav(P-O) = 1.5396 (7) Å], fused together via Zn-O-P links [θav = 133.47 (4)°]. An undisordered linear Zn-O-P bond occurs (all three atoms lie on a threefold axis). Extra-framework NH4+ cations, which interact with the [ZnPO4]− framework by hydrogen bonds, complete the crystal structure. [ABSTRACT FROM AUTHOR]

The crystal structure of tricaesium cobalt pentachloride has been determined by X-ray diffraction at 10 K. The Co atom is at a site with symmetry, one Cs atom is at a site with 42 symmetry, the other has mm site symmetry, one Cl ligand has 4/ m symmetry and the other has m symmetry. The accurate and extensive data set collected should be suitable for charge-density analysis studies. In the CoCl42− ion, as the temperature is lowered, the Co-Cl bond length increases a little and the small distortion of the tetrahedron (site symmetry 2 m) is slightly reduced. [ABSTRACT FROM AUTHOR]

The new Ni-catalyst is extremely effective in the amination reaction of various amines with arylchlorides and bromides. [ABSTRACT FROM AUTHOR]

The crystal structure of tripotassium sodium hexa­chloro­ferrate(II) has been determined by X-ray diffraction at 293, 84 and 9.5 K. The accurate and extensive data sets collected should be suitable for charge-density analysis studies. [ABSTRACT FROM AUTHOR]

Novel complexes of form (NHC)Au(SCOR) (NHC = N‐heterocyclic carbene, SCOR− = thiocarboxylate ligand) were synthesised and characterised by spectroscopic techniques and X‐ray diffraction studies. The results of NMR and X‐ray studies indicated that thiocarboxylate ligands are comparable with NHCs in their electron donor ability. The complexes were stable at room temperature in the solid state but in solution underwent disproportionation reactions to form equilibria with [Au(NHC)2]+ and [Au(SCOR)2]−. In solution, the thiocarboxylate ligand in (NHC)Au(SCOR) underwent rapid exchange with other thiocarboxylate or thiolate ligands. The (NHC)Au(SCOR) complexes showed toxicity against cisplatin‐resistant ovarian cancer cells (OVCAR‐8), with IC50 < 10 μM, in the range exhibited by cationic [Au(NHC)2]+ complexes well‐known for their promising anticancer activity. [ABSTRACT FROM AUTHOR]

The title compound, [Co(C7H3N2O6)2(C2H6OS)2(H2O)2], has been prepared and its structure established by an X-ray structure determination in order to assist the modelling of processes of chemisorption of organic salts formed by di­nitro­benzoic acids (DNBH) and secondary amines ( R2NH) by metal surfaces. The 2,4-DNB ions and di­methyl sulfoxide (DMSO) mol­ecules behave as monodentate ligands coord­inated to the Co atom through their O atoms. These ligands, together with two mol­ecules of water, form a slightly distorted octahedral coordination environment for the Co atom which is disposed at a centre of symmetry. [ABSTRACT FROM AUTHOR]

The single-crystal structure of a beta'-copper vanadium bronze, Cu0.63V2O5, has been studied at room temperature and 9.6 K, and compared with that of the beta-sodium vanadium bronze, Na0.33V2O5, structure. No convincing evidence to oppose an assignment of centrosymmetric C2/m symmetry to the structure was identified using the X-ray data. A subsequent convergent beam electron diffraction (CBED) experiment was performed and confirmed the C2/m space group. The oxygen-vanadium atom framework of Cu0.63V2O5 is close to that of Na0.33V2O5. However, in the copper compound the Cu atoms are located in two positions: Cu1 in the 4(i) position with x=0.541, y=0 and z=0.345, and Cu2 in the 8(j) position with x=0.529, y=0.038 and z=0.357. The crystal structure changes little with temperature. Disorder of the Cu ion over two sites is seen at 9.6 K. This suggests that distribution of the Cu atoms over two sites is of a more static than dynamic nature.

In order to model processes of chemisorption in organic salts formed between dinitrobenzoic acids (DNBH) and secondary amines (R(2)NH), a series of compounds of composition [M(II)(3,5-DNB)(2)(DMSO)(2)(H(2)O)(2)] (where M(II) is Zn, Cu, Ni or Co, 3,5-DNB is the 3,5-dinitrobenzoate ion, and DMSO is dimethyl sulfoxide) have been prepared. In diaquabis(dimethyl sulfoxide)bis(3,5-DNB)zinc(II), [Zn(C(7)H(3)N(2)O(6))(2)(C(2)H(6)OS)(2)(H(2)O)(2)], the 3,5-DNB ions and molecules of DMSO are monodentate ligands that are coordinated to the Zn atom through their O atoms. These ligands, together with two molecules of water, form a slightly distorted octahedral coordination environment for the Zn atom, which lies on a center of symmetry.