Syntheses of [Pt-6(CO)(8)(SnCl2)(SnCl3)(4)](4-) and [Pt-6(CO)(8)(SnCl2)(SnCl3)(2)(PPh3)(2)](2-) Platinum-Carbonyl Clusters Decorated by Sn-II Fragments

The reaction of [Pt-6(CO)(6)(SnCl2)(2)(SnCl3)(4)](4-) (1) with CO under atmospheric pressure resulted in the new [Pt-6(CO)(8)(SnCl2)(SnCl3)(4)](4-) (2) cluster by the addition of two CO ligands and the elimination of a stannylene SnCl2 group. In turn, 2 reacted with 2 equivalents of PPh3 under a CO atmosphere to afford [Pt-6(CO)(8)(SnCl2)(SnCl3)(2)(PPh3)(2)](2-) (3) by elimination of two stannyl [SnCl3](-) ligands. Conversely, the reaction of 2 with 2 equivalents of PPh3 under a N-2 atmosphere resulted in a species tentatively formulated as [Pt-6(CO)(5)(SnCl2)(2)(SnCl3)(2)(PPh3)(2)](2-) (4-5CO) on the basis of C-13 NMR, P-31 NMR spectroscopy and ESI-MS studies. Compounds 2-4 were spectroscopically characterized by IR spectroscopy and multinuclear (C-13 and P-31) variable-temperature NMR spectroscopy. The crystal structures of 2 and 3 were determined by means of single-crystal X-ray diffraction, and their bonding was computationally investigated by DFT calculations. The possible structure of 4-5CO was predicted by means of DFT methods.