Synthesis and structure of monomeric and platinum-bonded (1,10-phenanthroline)thallium complexes

Oxidative addition of (1,10-phenanthroline)thallium(III) complexes [Tl(phen)n(solv)]3+ (n = 1-2) (phen = 1,10-phenanthroline) to [Pt(CN)4]2- in DMSO, in the presence of cyanide ions and in the absence of cyanide ions yielded heterodinuclear metal-metal-bonded complexes, [(NC)5Pt-Tl(phen)n(solv)] and [(NC)4Pt-Tl(phen)n(solv)]+ (n = 0, 1, and 2), respectively. The presence of a direct Pt-Tl bond in the complex is evident by a very strong one-bond 195Pt-205Tl spin-spin coupling detected by 205Tl NMR: 1J = 94.0 kHz (1a), 84.2 kHz (2a), and 77.1 kHz (3a) corresponding to n = 0, 1, and 2 in [(NC)4Pt-Tl(phen)n(solv)]+, and 1J = 65.4 kHz (2b) and 62.5 kHz (3b) for n = 1 and 2, respectively, in [(NC)5Pt-Tl(phen)n(solv)]. The crystal structures of [(NC)5Pt-Tl-(phen)(DMSO)3]·(DMSO) (2b), [(NC)5Pt-Tl(phen)2]·(DMSO)3 (3b), and [Tl(phen)2Cl2] (ClO4) (4) complexes were determined. Very short Pt-Tl bonds, 2.6296(3) and 2.6375(5) Å, are present in structures 2b and 3b, respectively. The corresponding force constants in the molecules in the solid state, 1.84 and 1.74 N/cm for 2b and 3b, respectively, were calculated using Raman stretching frequencies of the Pt-Tl vibrations, and are characteristic for a single, strong metal-metal bond. Electronic absorption spectra were recorded for selected compounds and the optical transition attributed to the metal-metal bond was assigned. © Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.