DFT study on the electronic structure, energetics and spectral properties of several bis(organohydrazido(2-)) molybdenum complexes containing substituted phosphines and chloro atoms as ancillary ligands

A theoretical study of the geometrical and electronic structure of several structurally related bis(organohydrazido(2-))-molybdenum complexes containing substituted phosphines and chloro atoms as ancillary ligands, of formula [Mo(NNPh2)2Cl2(PPh3)2] (1), [Mo(NNPh2)2Cl2(PMePh2)2] (2), [Mo(NNPh2)2Cl2(PMe2Ph)2] (3), [Mo(NNPh2)2Cl2(PMe3)2] (4) and [Mo(NNPh2)2Cl2(PH3)2] (5), was carried out. In order to analyze the electronic effects when the phosphines are changed, a decomposition energy analysis was performed, finding that the Mo-Cl interactions have long distance and ionic character with poor “p” antibonding contributions. Besides, the metal-phosphine interactions have little covalent character, while the Mo-hydrazido(-2) interaction with significant orbital contribution, indicates a strong covalent character with respect to the rest of the ligands. On the other hand, the calculated electronic transitions using the Time-Dependent Density Functional Theory (TDDFT) are also presented at GGA and B3LYP theoretical levels, and despite of the limitations of the first method, we obtained a good correlation with B3LYP analysis performed. Also, the calculated excitations are in good agreement with the experimental data for (2) and (3), moreover, we were able to predict the electronic transitions that could be observed in the proposed (1), (4) and (5) complexes and these results indicate that these compounds are stable and they should be able to be synthesized.