Preparation and properties of difluorophosphino monothioacetate

Abstract

When difluorophosphino monothioacetate is prepared by the exchange reaction of PBrF₂ with CH₃COSSnBu₃(which contains an S–Sn bond) the isomer in which the difluorophosphino-group is bound to oxygen is formed first. When it is prepared from PBrF₂and CH₃CSOSiH₃(which contains an O–Si bond) the S-bonded isomer is formed. In each case equilibration then occurs to give ca. 80% O-bonded and 20% S-bonded at room temperature. Thermodynamic data are reported. The new ester has been isolated, and characterised by n.m.r., vibrational, and mass spectroscopy. Difluorophosphino monoselenoacetate has been prepared by analogous reactions, but it is unstable and has not been isolated.