Easy ring expansion and contraction in Pt–Sn bonded metallacycles

Abstract

The alkyne RCCR, R = CO₂Me, reacts with 5-membered metallacycles [PtMe₂{SnMe₂ESnMe₂E}(bu₂bpy)], E = S, Se or Te, bu₂bipy = 4,4′-di-tert-butyl-2,2′-bipyridine, yielding the corresponding 7-membered metallacycles [PtMe₂{SnMe₂ESnMe₂CRCRE}(bu₂bpy)] which slowly eliminate “Me₂SnE” to give new 5-membered metallacycles [PtMe₂{SnMe₂CRCRE}(bu₂bpy)]; further reaction of which with excess RCCR gives [PtMe₂(CRCRH)(CCR)(bu₂bpy)], a complex which contains alkyl, alkenyl and alkynyl functionalities in the same molecule.