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Notes: The title compound, [PtI2(S2C4H8)], consists of a 1,4-dithiane and two iodo ligands coordinated to a Pt atom in a distorted square-planar cis-system with Pt on a twofold axis. The dithiane forms a bidentate chelate with Pt, bonding via the S atoms. The Pt—I bonds are 2.6035 (5) Å and the Pt—S bonds 2.2751 (16) Å. The Pt—S bond is influenced mainly by the cis-chelate effect and the Pt—I bond by the trans-influence of sulfur.

Notes: Two different crystals (A and B) were used to structurally characterize trans-[PtCl2(PPh3)2] and to study random and systematic errors in derived parameters. The compound is isomorphous with trans-[PdCl2(PPh3)2] and with one of the polymorphs of trans-[PtMeCl(PPh3)2] reported previously. Half-normal probability plot analyses based on A and B show realistic s.u.'s and negligible systematic errors. R.m.s. calculations give very good agreement between A and B, 0.0088 Å. Important geometrical parameters are Pt—P = 2.3163 (11) Å, Pt—Cl = 2.2997 (11) Å, P—Pt—Cl = 87.88 (4) and 92.12 (4)°. Half-normal probability plots and r.m.s. calculations were also used to compare the title compound with the palladium analogue, showing small systematic differences between the compounds. The torsion angles around the Pt—P bond were found to be very similar to those reported for isomorphous complexes, as well as to the torsion angles around the Pt—As bond in trans-[PtCl2(AsPh3)2]. The NMR coupling constants for the title compound are similar to Pt—P coupling constants reported for analogous trans complexes.

Notes: The Pd atom in each of the two title compounds, [Pd(NO3)2(C2H6OS)2], (I), and [Pd(NO3)2(C4H8OS)2], (II), coordinates two O atoms from two nitrate ligands and two S atoms from dimethyl sulfoxide (dmso) and thioxane (systematic name: 1,4-oxathiane) ligands in a pseudo-square-planar cis-geometry. In the dmso complex, the distances to palladium are Pd—O 2.067 (2) and 2.072 (2) Å, and Pd—S 2.2307 (11) and 2.2530 (8) Å. The corresponding distances in the thioxane complex are Pd—O 2.053 (3) and 2.076 (2) Å, and Pd—S 2.2595 (9) and 2.2627 (11) Å. Both compounds may be regarded as dimers with an inversion centre, where one of the coordinating nitrate O atoms in one molecule also interacts with the Pd atom in the adjacent molecule, with Pd—O distances of 2.849 (9) and 3.31 (3) Å in (I) and (II), respectively.

Notes: Both cis- and trans-dichlorobis(diphenyl sulfide)platinum(II), [PtCl2(C12H10S)2], crystallize as mononuclear pseudo-square-planar complexes. In the cis compound, the Pt—Cl distances are 2.295 (2) and 2.319 (2) Å, and the Pt—S distances are 2.280 (2) and 2.283 (2) Å. In the trans compound, Pt is located on a centre of inversion and the Pt—Cl and Pt—S distances are 2.2786 (15) and 2.3002 (12) Å, respectively.

Notes: A series of structures of trans-dichlorobis(triphenylarsine)platinum(II), recrystallized from four different solvents, have been characterized by X-ray crystallography and were shown to crystallize as different solvates (same metal complex, different crystallization solvents). Their geometric differences induced by packing and solvent molecules were analysed with half-normal probability plots and root-mean-square deviations. The recrystallization solvents used in the investigation were 1,1,1-trichloroethane, dichloromethane, 1,2-dichloroethane and benzene, and the following crystallization modes were obtained. From 1,1,1-trichloroethane the metal complex crystallizes without solvent as trans-[PtCl2(AsPh3)2] in P21/n with Z = 2, a = 9.271 (2), b = 19.726 (4), c = 9.830 (2) Å, β = 111.83 (3)°, V = 1668.8 (6) Å3, R = 0.0262, and from dichloromethane with two solvent molecules as trans-[PtCl2(AsPh3)2]·2CH2Cl2 in Pbca with Z = 4, a = 20.582 (4), b = 8.146 (2), c = 23.491 (5) Å, V = 3938.5 (14) Å3 and R = 0.0316. From dichloroethane it crystallizes with one solvent molecule as trans-[PtCl2(AsPh3)2]·C2H4Cl2 in P\overline 1 with Z = 1, a = 9.390 (2), b = 9.548 (2), c = 11.931 (2) Å, α = 109.70 (3), β = 108.26 (3), γ = 98.77 (3)°, V = 915.6 (3) Å3, R = 0.0390, and from benzene with half a solvent molecule as trans-[PtCl2(AsPh3)2]·0.5C6H6 in P21/n with Z = 4, a = 11.778 (2), b = 18.712 (4), c = 16.647 (3) Å, β = 104.78 (3)°, V = 3547.3 (12) Å3 and R = 0.0303. In all four compounds platinum(II) coordinates to triphenylarsine and chloride in a pseudo-square-planar trans configuration. The Pt—As distances are in the range 2.4104 (4)–2.3923 (4) Å and the Pt—Cl distances are in the range 2.309 (2)–2.2839 (9) Å. The solvents have a large influence on the packing, resulting in different space groups or different occupancies in the same space group. Half-normal probability plots show that the largest geometric differences, within the metal complex, are in the bond and torsion angles around the As—C bonds. Very similar torsion angles were observed around the Pt—As bond for all the structures, except for one AsPh3 ligand in the benzene solvate, which differs by about 10° from the others. The metal–donor bond distance varies by as much as 0.019 and 0.025 Å (95% confidence interval) for Pt—As and Pt—Cl, respectively. The variations are essentially caused by intermolecular interactions. Packing efficiency is expressed as the volume filled by each metal complex in the unit cell and is calculated by subtracting the sum of the solvent molecule volumes from the total volume of the unit cell and then dividing by Z. The efficiency is largest in the dichloroethane solvate and smallest in the non-solvated compound, with a difference of approximately 22 Å3 per metal complex.