Analysis of newly synthesized disulfides of aryldithiocarbonates and vanadium(V) and niobium(V) complexes of aryldithiocarbonates based on spectroscopic, thermogravimetric, SEM and DFT studies

Oxidation of the sodium salt of 2-methyl, 3-methyl, 4-methyl and 4-chloro-3-methylphenyldithiocarbonic acid by I-2 affords the disulfides of respective dithiocarbonates [(ArOCS2)(2)] (Ar = 2-CH3C6H4, 3-CH3C6H4, 4-CH3C6H4 and 4-Cl-3-CH3C6H3. Vanadium(V) and Niobium(V) complexes of 2-methyl, 3-methyl, 4-methyl and 4-chloro-3-methylphenyldithiocarbonates have also been synthesised by one-step synthetic route. The metal salt (VOCl3 and NbCl5) were reacted with 2-CH3C6H4, 3-CH3C6H4, 4-CH3C6H4 and 4-Cl-3-CH3C6H3OCS2Na in 1:2 stoichiometric molar ratio yielding the complexes corresponding to the molecular formula [(ArOCS2)(2)VO(Cl)] and [(ArOCS2)(2)NbCl3] [Ar = 2-CH3C6H4, 3-CH3C6H4, 4-CH3C6H4 and 4-Cl-3-CH3C6H3OCS2)]. The compounds were characterised by elemental analyses, infrared, mass and heteronuclear NMR (H-1 and C-13) spectroscopic studies. Thermogravimetric analysis and scanning electron microscopic analyses were also carried out for deeper investigation of the structural features. Comprehensive theoretical investigation was performed by applying density functional theory (DFT) calculations on vanadium and niobium complexes by the DFT/B3LYP/LANL2DZ method to obtain the optimised molecular geometry, vibrational frequencies, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), thermodynamic properties and various other quantum-mechanical parameters.