Mononuclear and Binuclear Complexes of Platinum(0) Containing (Alkynyl)phenylsilanes

Abstract

Reaction of bis(cycloocta-1,5-diene)platinum(0) with the (alkynyl)phenylsilanes Ph₃SiC₂Bu^t, Ph₂Si(C₂Bu^t)₂ and PhSi(C₂Bu^t)₃ gives, respectively, [Pt (Ph₃SiC₂Bu^t)₂] (1b), [Pt {Ph₂Si(C₂Bu^t)}]₂ (2b), and [Pt {PhSi(C₂Bu^t)₃}]₂ (4b), which contain zerovalent platinum atoms coordinated by two alkyne units. Spectroscopic data indicate that (2b) and (4b) contain two PtC₄ and two SiC₄ tetrahedra joined at the corners. X-Ray crystallography shows that complex (4b) is isostructural and isomorphous with the known nickel analogue, two of the alkyne units being uncoordinated; the central eight-membered ring comprising two silicon, four alkyne carbon and two platinum atoms has an approximate chair conformation. In contrast, the monomer (1b) is isostructural but not isomorphous with the analogous nickel compound (1a); in the crystal there is evidence for a weak intramolecular phenyl-phenyl interaction.