Exchange reactions of bromodifluorophosphine with silyl and germyl derivatives of the Group VI elements

Abstract

The reactions of PF₂X (X = Cl or Br) with (MH₃)₂Y (M = Si or Ge; Y = O, S, Se, or Te) have been studied by n.m.r. spectroscopy. When X = Br and Y = S, Se, or Te, reaction occurs at room temperature to give the species MH₃YPF₂, (PF₂)₂Y, and MH₃Br. ¹⁹F and ¹H N.m.r. and double-resonance techniques have been used to determine the chemical shifts (¹H, ¹⁹F, ³¹P, and ⁷⁷Se) and coupling constants (including relative signs) of the products. The PF₂Se– and PF₂Te– compounds have exceptionally low ³¹P chemical shifts. The ¹⁹F spectrum of (PF₂)₂Se has been studied over a wide range of temperatures, and ²J(PP) and both ⁴J(FF) values are found to be strongly temperature-dependent. The ¹H spectrum of SiH₃TePF₂ is also temperature-dependent.