Coordination chemistry of bisstannylenes with platinum(0)

Reaction of stoichiometric amounts of the benzannulated bisstannylene 1 with [Pt(nbe)(3)] in the presence of PPh(3) and OPPh(3) gave complex 3 with an Sn(2)PtP(2) core and an O=PPh(3) molecule coordinated to one of the stannylene donors according to an X-ray diffraction study. Complex 3 was also obtained by substitution of two PPh(3) ligands in [Pt(PPh(3))(4)] by the bisstannylene 1 in the presence of OPPh(3). 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 (119)Sn NMR spectra for complex 5 with the 1,3-(CH(2))(2)C(6)H(4) bridging unit between the stannylene donors indicate the presence of an equilibrium between complexes with three- and tetra-coordinated platinum atoms in solution.