Bis(cyclopentadienyl)dihydrido Mo and W complexes as Lewis bases — A computational study about their adducts with BX3 (X = F, Cl) and Al(CH3)3

A computational investigation about the Lewis acid–base adducts between bases Cp2MH2 (M = Mo, W) and acids BX3 (X = F, Cl) and Al(CH3)3 is presented. Density functional methods based on pure and hybrid correlation-exchange functionals and relativistic corrections based on the zero order relativistic approximation (ZORA) have been applied. A comparison with experimental data has been addressed to give insights about the nature of the acid–base interaction with the aim to evaluate the role of the transition metal in charge donation toward the acid centre. In this respect, the likelihood of proposed criteria for recognizing the presence of transition-metal direct charge donation has been discussed.