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  • Author: Peter G. Jones x
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The space group of the title compound is probably C2/m rather than the previously reported C2.

Abstract

The crystal structure of the title compound has been determined (P3c 1, a = 2161.5(3), c = 2859.8(4) pm, Z = 6; Rw = 0.07 for 2217 observed reflections). There are three independent (Ph3Sb)4Au+ cations, each with one Au-Sb bond directed along a crystallo-graphic threefold axis. Deviations from ideal tetrahedral coordination are small (max. 8 pm, 1°).

Abstract

The crystal structure of (OC)AuCl has been determined and refined to R 0.037 (space group Cmcm, a = 407.1(1), b = 1042.2(4), c = 532.1(3) pm, Z =4). The structure consists of discrete, exactly linear molecules; all atoms lie on the special positions 0, y, 1/4. The bond lengths involving the light atoms are affected by libration. The shortest Au ··· Au contacts between molecules are 338 pm.

The complexes Ph2SeAuCl (green) and Ph2SeAuCl3 (brown) are prepared by direct reaction between the diphenylselenide ligand and the corresponding gold chloride. The crystal structures confirm the presence of monomeric, linear (AuI) or square planar (AuIII) coordinated complexes with bond lengths A u(I)-Se 2.378(1), Au(III)-Se 2.445(1) Å. Short non-bonded contacts Au(I) ··· Au(I) and Au(III) ··· Cl are observed.

The binuclear complex [(Ph3PAu)2Se(p-C6F4Cl)]+SbF6 - was prepared from Ph3PAuCl and (p-C6F4Cl)2Se2 in the presence of AgSbF6. The crystal structure shows a short intramolecular gold-gold interaction, which leads to an extreme distortion in the coordination geometry at selenium.

All three structures of the form bis(thione)gold(I) camphor-10-sulfonate [thione = imidazolidine-2-thione, 1; 1-methyl-imidazolidine-2-thione, 2; thiazolidine-2-thione, 3] crystallize in chiral space groups with Z′ = 2; local inversion symmetry of the cationic assemblies (less pronounced for 3) provides some rationalisation for this. The basic structural units are accounted for in terms of classical hydrogen bonds, leading to rings involving ion pairs for 1 and 2, but to infinite chains of anions and cations for 3. Neighbouring ion pairs in 1 are joined by further classical hydrogen bonds, in 2 via interactions between parallel S-Au-S axes. Other interactions include Au···N for 1, Au···S and Au···O for 3, and weak hydrogen bonds C-H···O and C-H···S, especially between adjacent chains in 3. Each structure is divided into hydrophobic and hydrophilic regions.

Abstract

The title compound contains three independent formula units. There is a large spread of values for chemically equivalent dimensions, notably in the cations, which display tetrahedral coordination at silver; Ag–N 2.228(4)–2.315(5) [av.2.266] Å, N–Ag–N 104.6(2)–115.7(2) [av. 109.6]°.

In the crystal structure of (dppmSe)2Au+ N(SO2CH3)2- (dppm = Ph2PCH2PPh2) chains are formed from non-conventional hydrogen bonds of the type C -H ···O . Within these chains two bifurcated hydrogen bond systems are present, each involving one methylene hydrogen (H···O 2.51, 2.65 Å) and one phenyl hydrogen (H···O 2.31, 2.35 Å) as donors.

The packing of all ten isomers of di(bromomethyl)naphthalene is analysed; nine of the structures were determined here, one (the 1,8-isomer) was already known. The 1,5- and 2,6-isomers display crystallographic inversion symmetry and the 2,7-isomer mirror symmetry through the central bond. For the 1,2-, 1,7- and 2,7-isomers, the bromomethyl groups point to the same side of the ring system, and for all other isomers to opposite sides. As expected, the molecules are linked into aggregates by various types of interactions: weak hydrogen bonds CH...Br, Br...Br interactions, CH...π contacts, π...π stacking and Br...π contacts. The weak hydrogen bonds tend to be numerous but relatively long, and do not combine to form readily recognisable patterns; a more readily assimilated view of the packing is based on the Br...Br interactions, which are observed for all isomers except 1,7 and 2,3, and in some cases lead to aggregation to form quadrilaterals or chains. With decreasing frequency, the interactions π...π, C-H...π and Br...π are observed, but the latter are rare (just two examples) and very asymmetric, with contacts to only one or two carbons.