A theoretical study of the cleavage of the amide bond of formamide by attack of the hydroxyl ligand in [Mo(OH)(η3-C3H5)(CO)2(N2C2H4)] and [Re(OH)(CO)3(N2C2H4)] complexes

The cleavage of the amide bond of formamide in dichloromethane by attack of the hydroxyl ligand in [Mo(OH)(η3-C3H5)(CO)2(N2C2H4)] and [Re(OH)(CO)3(N2C2H4)] complexes was theoretically investigated at the B3LYP/6-31+G(d) level (LANL2DZ for Mo and Re atoms). The effect of CH2Cl2 as solvent was evaluated by the PCM-UAHF method. According to our theoretical results the more favorable mechanisms for these reactions are concerted. The energy barriers obtained by us (54.6 kcal mol−1 for [Mo(OH)(η3-C3H5)(CO)2(N2C2H4)] and 51.9 kcal mol−1 for [Re(OH)(CO)3(N2C2H4)]) are higher than those found for the neutral hydrolysis of formamide in water (about 44-46 kcal mol−1). In contrast with water solvent, the effect of bulk CH2Cl2 is quite important increasing the barriers of these two concerted processes by about 2 and 6 kcal mol −1, respectively, and making more favorable the concerted mechanism in solution in the case of the Mo complex.