New molybdenum(VI) complexes with bidetantete (N,N), (N, S), and (S, S) ligands spectral characterization and theoretical calculations

Abstract

[MoO2(acac)(ATP)], [MoO2(4CPD)(ATP)], [MoO2(ATP)2], and [MoO2(ATP)(DTO)] are four new MO(VI) complexes have been synthesized, where (acac) is acetylacetone, (ATP) is 2-aminothiophenol, (4CPD) is 4-chloro-ophenylenediamine, and (DTO) is dithiooxamide. The complexes were characterized using a variety of spectral techniques, such as mass spectroscopy, 1 H NMR, FT-IR, UV–Vis., and theoretical calculations. The FT-IR spectra showed that the oxygen, nitrogen, and sulfur atoms coordinated the ligands with the MO(VI) ion. The mass spectrum of each complex describes its mononuclear structure. The complexes are diamagnetic and have an electrical configuration of d0 . The complexes’ lowest unoccupied molecular orbitals ranged in energy from − 0.095 to − 0.260 a.u., while their highest occupied molecular orbitals ranged from − 0.347 to − 0.373 a.u., according to the computational results. The complexes were found to be softer and more soluble than the free ligands. The prepared complexes feature distinct coordination environments around the MO(VI) ion, specifically: (2O, N, S), (3N, S), (2N, 2S), and (N, 3S). This variation in the percentage of sulfur atoms surrounding the Mo(VI) ion was intentionally designed based on Pearson’s Hard and Soft Acids and Bases theory. The comparatively easier electronic transitions observed in the complexes, relative to the free ligands, suggest their potential for future application in photocell research. For each complex, a distorted octahedral geometry was proposed based on the calculated bond lengths and bond angles.