Synthesis and X-ray crystal structure of bis(tetrahydroborato)bis[1,5-bis(diphenylphosphino)pentane]dicobalt(I), Co2(BH4)2(Ph2P[CH2]5PPh2)2·0.5C6H6: a novel mode of tetrahydroborate co-ordination

Abstract

The title compound, obtained as one of several intermediates in a complex sequence of reactions involving Co^II, NaBH₄, and α,ω-bis(diphenylphosphino)alkanes, is isolated as a phosphine-bridged binuclear species in which each of two tetrahydroborato groups also bridges the two Co^I units via the previously unknown M–H–BH₂–H–M type of linkage; an additional and unexpected feature of the X-ray crystal structure is that one hydrogen atom of each of the two central BH₂ groups also acts as a bridging ligand.