Carbonyl halides of the Group VI transition metals. XVI. Reactions of Bis(diphenylphosphino)methane with Diiodotetracarbonyltungsten(II)

Abstract

Compounds of the general formulae W(CO)₃dpmI₂ and W(CO)₂(dpm)₂I₂ [dpm = bis(diphenylphosphino)methane] have been prepared by direct interaction of the ligand with diiodotetracarbonyltungsten(II). However, this apparently simple system is complicated by the existence of two isomers of the tricarbonyl complex and three isomeric forms of the dicarbonyl. The various isomers have been separated and characterized individually and the interconversions between all the complexes have been investigated. The overall reaction scheme contains a partial carbon monoxide carrying system and an example of an unusual type of isomerism:                      W(CO)₂(dpm)₂I₂ → [W(CO)₂(dpm)₂I]I that is, isomerism of a molecular species to an ionic species.