Simulation investigation of bis(pentaphospholyl)metallocenes of Fe, Ru, and Os

摘要

The structures, stabilities, and bonding features of neutral M(η~5-P_5)_2 (M = Fe, Ru, and Os) and cationic M(η~5-P_5)~+ have been investigated using density functional theory (DFT) (hybrid B3LYP and pure BP86 methods). The eclipsed (D_(5h)) structure has been predicted to be the global minimum for this triad bis(pentaphospholyl) metallocenes, and the staggered (D_(5d)) structure to be the rotational transition state. The distances between the metal and cyclo-P5 center in bis(pentaphospholyl) metallocenes are longer than in the corresponding M(η~5-P_5)~+ by 0.28-0.38 A. The M(η~5-P_5)~+ complexes may be tighter binding with the shorter metal-ring distances, the possible reason is that there being stronger metal-ring n interactions in M(η~5-P_5)~+ than in M(η~5-P_5)_2, even though latter satisfies the 18-electron rule. The electron densities are found to accumulate at the metal centers, this novel situation may have an impact on the mechanism of some potential catalysis reactions.