Novel porphyrin-thallium-platinum complex with 'naked' metal-metal bond : multinuclear NMR characterization of [(tpp)Tl-Pt(CN)(5)](2-) and [(thpp)Tl-Pt(CN)(5)](2-) in solution

The novel porphyrin-thallium-platinum complexes with "naked" metal-metal bond, with the composition [(tpp)Tl-Pt(CN)(5)](2-) (1) and [(thpp)Tl-Pt(CN)(5)](2-) (2) (tpp = tetraphenylporphrin and thpp = tetrakis(4-hydroxyphenyl)-porphine), were synthesized and characterised by multinuclear NMR (Tl-205, Pt-195, C-13 and H-1) and Raman spectroscopies in solution. The presence of a direct Pt-Tl metal-metal bond in the complexes is convincingly confirmed by a very strong one-bond Pt-195-Tl-205 spin-spin coupling (47.8 and 48.3 kHz for 1 and 2, respectively) detected in both Pt and Tl NMR spectra. The corresponding force constant in molecule 1, 1.92 Ncm(-1), was calculated using Raman stretching frequency of the Pt-T1 vibration and is characteristic for a single metal-metal bond. (C) 2004 Elsevier B.V. All rights reserved.