Abstract
Two cis-bis-dioxomolybdenum oxalylsalicylidenedihydrazone complexes (MoO(2)L1 and MoO(2)L2) were synthesized via the complexation of dioxomolybdenum (VI) acetylacetonate with oxalylsalicylidenedihydrazone (H(2)L1) and p-sodium sulfonate oxalylsalicylidenedihydrazone (H(2)L2) bis-Schiff base chelating ligands, respectively. The structures of the newly synthesized complexes were confirmed by H-1- and C-13-NMR, IR, ultraviolet-visible and mass spectra, as well as elemental analyses (EA) and conductivity measurements. The spectrophotometric continuous variation method revealed the formation of 2: 1 (metal: ligand molar ratios). DFT studies were applied for the ligands and their Mo-chelates. Interestingly, the bis-MoO2(VI) oxalyldihydrazone complexes showed remarkable catalytic sufficiency towards the selective (ep)oxidation of 1,2-cyclooctene, benzyl alcohol and thiophene using H2O2 or tert-butyl hydroperoxide (tBuOOH) at 85 degrees C. Under aqueous conditions, the MoO(2)L2 (with p-sodium sulfonate substituent) exhibited superior that of the MoO(2)L1 (without p-NaSO3?group), highlighting the role of sodium sulfonate substituent in the catalytic progress of the Mo-chelate. The ligands (H(2)L1 and H(2)L2) and their corresponding Mo-complexes (MoO(2)L1 and MoO(2)L2) were assessed for their antitumor and antimicrobial activities. Furthermore, the antioxidant activity was also evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide dismutase (SOD) assays. The binding nature between the Mo-complexes and calf thymus DNA (ctDNA) was also studied within spectroscopic and hydrodynamic techniques.