THEORETICAL-STUDY OF ELECTROPHILIC VERSUS NUCLEOPHILIC CHARACTER OF TRANSITION-METAL COMPLEXES OF PHOSPHINIDENE

A comparative theoretical study of the terminal phosphinidene complexe s HPCr(CO)(5), HPTi(Cp-2) and HPTiCl2, at the MP2 and DFT levels, has been carried out. The calculated results have then been used for deter mining the electron localization function (ELF) in these moieties. Bot h techniques show that in the singlet ground state of HPCr(CO)(5), one gets a weak double P-Cr bond, with an electrophilic character on P (i .e. electron-deficient center). Conversely, in the singlet ground stat e of Ti complexes, the P-Ti bond shows a greater double bond character than in the P-Cr linkage, associated with an overall nucleophilic cha racter of P. These results are in good agreement with all available ex perimental data. (C) 1998 Elsevier Science S.A. All rights reserved.