Syntheses and crystal structures of lithium derivatives of diphosphanes R2P-P(SiMe3)Li•3L, R = Ph, iPr and iPr2N, L = THF or DME

The reactions of R2P-P(SiMe3)(2) (R = Ph, Pr-i and (Pr2N)-Pr-i) with BuLi in THF or DME solution lead to ion-contacted lithium derivatives R2P-P(SiMe3)Li center dot 3THF (R = Pr-i, (Pr2N)-Pr-i) with tetrahedrally surrounded Li atoms and to the solvent-separated ionic [Li center dot 3DME](+)[Ph2P-PSiMe3](-) with an octahedrally surrounded Li atom as confirmed by X-ray crystal structure analysis. The reaction of BuLi with Ph2P-P(SiMe3)(2) is accompanied with a significant side-reaction leading to Ph2P-PPh2 and to LiP(SiMe3)(2.) (C) 2007 Elsevier Ltd. All rights reserved.