Small Platinum−Thallium Clusters Stabilized by Ethylenediamine, [(NC)5Pt−Tl(en)n−1] (n = 1−3) − Characterization in Solution and in the Solid State

Abstract

Three neutral binuclear platinum−thallium compounds containing a direct and “naked” (unsupported by ligands) metal−metal bond have been prepared in dimethyl sulfoxide (DMSO). The compounds have the formula [(NC)5Pt−Tl(en)n−1] (n = 1−3, for compounds 1, 2 and 3, respectively) and were found to exist in solution by means of multinuclear NMR (195Pt, 205Tl, 13C and 1H) and Raman spectroscopy. The compounds exhibit very large single bond 195Pt−205Tl spin-spin coupling constants of 48−66 kHz. In addition, the solid state analogues of 1 and 3, [(NC)5Pt−Tl(DMSO)4](DMSO) and [(NC)5Pt−Tl(en)2](DMSO)2, were synthesized and their structures determined by single crystal X-ray diffraction. The metal−metal bond lengths of Pt−Tl are 2.6131(4) Å and 2.6348(5) Å in compounds 1 and 3, respectively. Crystal data for compound 1: monoclinic, space group Cc (No. 9), Z = 4, a = 17.2367(14), b = 9.5560(11), c = 17.7941(15) Å, β = 100.551(10)°, V = 2881.4(5) Å3, T = 110(1) K; and for compound 3: monoclinic, space group P21 (No. 4), Z = 2, a = 9.3167(14), b = 12.3007(13), c = 11.4586(16) Å, β = 112.318(16)°, V = 1214.8(3) Å3, T = 110(1) K.