A computational investigation of structural and spectroscopic properties of [MoCp 2 (6-mercaptopurine)] + complexes

A computational investigation was reported to illustrate the structure, bonding, and spectroscopic properties of two isomers of [MoCp2(6-mercaptopurine)]+ complex. Quantum chemistry computations were considered with mPW1PW91 functional, 6–311 G(d,p) (for main group atoms) and the Def2-TZVPPD (for Mo) basis sets. Two possible isomers were considered by the interaction of interactions of MoCp2 with N5 atom (A) and MoCp2 with N3 atom (B). Energetic stability and polarity of the two isomers were explored. Energetic stability was found for B-complex than A-complex. Energy decomposition analysis (EDA), the natural bond orbital (NBO) approach, and the electron localization function (ELF) provided a significant understanding of the nature and strength of the molybdenocene and 6-mercaptopurine binding. Charge decomposition analysis (CDA) was used to illustrate the charge transfer between two fragments. CDA results revealed larger charge transfer was occurred from 6-mercaptopurine ligand to MoCp2 fragment for two complexes. Additionally, the 14N NQR parameters of two complexes of [MoCp2(6-mercaptopurine)]+ were calculated.