Increasing the lability of polarised phosphorus-phosphorus bonds

Diphosphanes with polarised P-P bonds react readily with Lewis acids like borane, gallium trichloride, or with elemental selenium, to give products arising from electrophilic attack at the more basic phosphorus atom and consecutive bond cleavage. Spectroscopic studies proved that the initial reaction with borane proceeds under preservation of the P-P bond to give a transient phosphane-borane which rearranged below ambient temperature. The results suggest that Lewis acid coordination decisively enhances the weakening of the polarised P-P bond. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).