A mechanistic study of the C–P bond cleavage reaction of 1,2-(PH2)2-C6H4 with nBuLi/Sb(NMe2)3

Abstract

In situ 31P NMR spectroscopic studies of the reaction of the primary diphosphine 1,2-(PH2)2-C6H4 with the mixed-metal base system nBuLi/Sb(NMe2)3, combined with X-ray structural investigations, strongly support a mechanism involving a series of deprotonation steps followed by antimony-mediated reductive C-P bond cleavage. The central intermediate in this reaction is the tetraphosphide dianion [C6H4P2]2(2-) ([]) from which the final products, the 1,2,3-triphospholide anion [C6H4P3]- () and [PhPHLi] (.Li), are evolved. An EPR spectrocopic study suggests that homolytic C-P bond cleavage is likely to be involved in this final step.