A density functional study of the dimerization of phosphaalkynes in the presence of transition metal fragments

The dimerization of phosphaalkynes (R-C=P, R = H, Me, tBu) without and with the presence of transition metal fragments, including CpCo (Cp = cyclopent adienyl) and COT-Ti (COT = cyclooctatetraene), has been probed using densit y functional theory calculations (B3LYP with different basis sets). MP2 and CCSD(T) calculations were also performed for the [H2C2P2] systems. In an a ttempt to address the exciting controversy and uncertainty about phosphaalk yne dimerization, a number of dimer formation mechanisms proposed in the li terature have been examined. Some new and plausible intermediates have also been identified.