Reaction of Terminal Phosphinidene Complexes with Dihydrogen

The reaction of H2 with [RP-W­(CO)5] (R =
Ph, Me) above 120 °C leads, first, to the secondary diphosphine
complex (RPH-PHR)­(W­(CO)5)2 and then to the primary
phosphine complex (RPH2)­(W­(CO)5). On the basis
of DFT calculations, the mechanism most likely involves the addition
of H2 to the P–W bond, followed by the formation
of the radical [RPH-W­(CO)5]• by homolysis
of the W–H bond. In the case of [PhNHP-W­(CO)5],
the hydrogenolysis takes place at the P–N bond and ultimately
produces the secondary diaminophosphine complex ((PhNH)2PH)­(W­(CO)5).

氢气（H₂）与[RP-W(CO)₅]（R=苯基（Ph）、甲基（Me））在120℃以上条件下反应时，首先生成仲双膦配合物（secondary diphosphine complex）(RPH-PHR)·(W(CO)₅)₂，继而生成伯膦配合物（primary phosphine complex）(RPH₂)·(W(CO)₅)。基于密度泛函理论（DFT）计算结果，该反应的机理大概率涉及氢气加成至P-W键，随后通过W-H键的均裂生成自由基[RPH-W(CO)₅]·。对于[PhNHP-W(CO)₅]体系，氢解反应发生于P-N键处，最终生成仲二氨基膦配合物（secondary diaminophosphine complex）((PhNH)₂PH)·(W(CO)₅)。