Coordination chemistry of bisstannylenes with platinum(0)

Abstract

Reaction of stoichiometric amounts of the benzannulated bisstannylene 1 with [Pt(nbe)₃] in the presence of PPh₃ and OPPh₃ gave complex 3 with an Sn₂PtP₂ core and an OPPh₃ molecule coordinated to one of the stannylene donors according to an X-ray diffraction study. Complex 3 was also obtained by substitution of two PPh₃ ligands in [Pt(PPh₃)₄] by the bisstannylene 1 in the presence of OPPh₃. The reaction of 2 equivalents of the bisstannylenes 1 and 2 exhibiting different spacers between the stannylene donors with one equivalent of [Pt(nbe)₃] gave the intensely coloured homoleptic [Pt(bisstannylene)₂] complexes 4 and 5. Both complexes were characterized by X-ray diffraction studies which demonstrated the presence of four identical tin atoms for complex 4 and two different types of tin atoms for complex 5. Temperature dependent ¹¹⁹Sn NMR spectra for complex 5 with the 1,3-(CH₂)₂C₆H₄ bridging unit between the stannylene donors indicate the presence of an equilibrium between complexes with three- and tetra-coordinated platinum atoms in solution.