Theoretical Study on the cooperativity/anticooperativity of metal–carbonyl and metal–dihydrogen bonds in some complexes of group ۶transition metals

The aim of this project is to study the structure, interaction energy, stabilization energy,cooperative/anticooperative energy and the nature of the metal-ligand bond in some group ۶transition metal complexes containing dihydrogen and carbonyl ligands. For this project, somecomplexes with the general formula [M(η۲-H۲)(CO)۴L] (M=Cr, Mo or W; L= SiO, PH۳,NO+,N۲,NC−, CS,CO, and CN−) were selected [۱-۳]. It should be noted that, ligand L is in the cisor trans position to the dihydrogen ligand. To carry out this project, the initial structures of theabove complexes were optimized by Gaussian۰۹ computing software at the BP۸۶ and B۳LYPlevels and using the def۲-TZVPP basis set. Then, the values of total interaction and stabilizationenergies, cooperative energy and the length of M–(η۲-H۲), M−CO and M–L bonds in theoptimized complexes were calculated and compared. Then, using NBO calculations, the amountof the natural charges of atoms, hybrid orbitals and bond orders were checked in each complex.Good correlations were observed, only in trans isomers, between the values of positivecooperative energies with the length and Wiberg bond order of the M–(η۲-H۲) bond. The lowestbond order and the longest M–(η۲-H۲)bond length were observed for the complexes that have thehighest values of anticooperative energies between (η۲-H۲)–M(CO)۴ and M(CO)۴–L bonds. Also,in all the trans complexes, the nature of bondswas investigated by the Energy DecompositionAnalysis (EDA) method.

کلیدواژه ها:

Theoretical Study ، Dihydrogen complexes ، Interaction and stabilization energies ، NBO calculation ، EDA analysis