Structure and Bonding Energy Analysis of Cobalt, Rhodium, and Iridium Borylene Complexes [(η~5-C_5H_5)(CO)M(BNX_2] (X = Me, SiH_3, SiMe_3) and [(η~5-C_5H_5)(PMe_3)M{BN(SiH_3)_2}] (M = Co, Rh, Ir)

摘要

Geometry, electronic structure, and bonding analysis of the terminal neutral borylene complexes of cobalt, rhodium, and iridium [(η~5-C_5H_5)(CO)M(BNMe_2)] (I, M = Co, II, M = Rh, III, M = Ir), [(η~5-C_5H_5)(CO)M{BN(SiH_3)_2)}] (IV, M = Co, V, M = Rh, VI, M = Ir), [(η~5-C_5H_5)(CO)M{BN- (SiMe_3)_2)}] (VII, M = Co, VIII, M = Rh, IX, M = Ir), and [(η~5-C_5H_5)(PMe_3)M{BN(SiH_3)_2}] (X, M = Co, XI, M = Rh, XII, M = Ir) were investigated at the BP86 level of theory. The calculated geometry parameters of iridium borylene complex [(η~5-C_5H_5)(CO)Ir{BN(SiMe_3)_2}] are in excellent agreement with their available experimental values. Pauling bond order of the optimized structures of I-XII shows that the M-B bonds in these complexes are nearly MdB double bonds, which is also supported by the performed energy decomposition analysis. The orbital interactions between the metal and boron arise mainly from M←BNX_2 σ-donation. In all complexes, the π-bonding contribution is smaller (26.2-37.0% of total orbital contributions) and increases via M = Rh < Co