Bis‐dioxomolybdenum (VI) oxalyldihydrazone complexes: Synthesis, characterization, DFT studies, catalytic epoxidation potential, molecular modeling and biological evaluations. (11th February 2020) - Adam, Mohamed Shaker S.
Abstract : Two cis ‐ bis ‐dioxomolybdenum oxalylsalicylidenedihydrazone complexes (MoO2 L1 and MoO2 L2) were synthesized via the complexation of dioxomolybdenum (VI) acetylacetonate with oxalylsalicylidenedihydrazone (H2 L1) and p ‐sodium sulfonate oxalylsalicylidenedihydrazone (H2 L2) bis ‐Schiff base chelating ligands, respectively. The structures of the newly synthesized complexes were confirmed by 1 H‐ and 13 C‐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 H2 O2 or tert ‐butyl hydroperoxide ( t BuOOH) at 85 °C. Under aqueous conditions, the MoO2 L2 (with p ‐sodium sulfonate substituent) exhibited superior that of the MoO2 L1 (without p ‐NaSO3 ―group), highlighting the role of sodium sulfonate substituent in the catalytic progress of the Mo‐chelate. The ligands (H2 L1 and H2 L2) and their corresponding Mo‐complexes (MoO2 L1 and MoO2 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. Abstract : Two cis ‐dioxo‐molybdenum oxalylsalicylidenedihydrazone complexes were synthesized and fully characterized. The catalytic reactivity of the bis ‐MoO2 (IV) oxalyldihydrazone complexes was investigated in the (ep)oxidation of 1, 2‐cyclooctene, benzyl alcohol and thiophene using H2 O2 or tert ‐butyl hydroperoxide, under aqueous conditions. Both the ligands and their bis ‐MoO2 (IV) complexes were assessed for antitumor and antimicrobial activities. The antioxidant activity was also evaluated. The binding nature of the bis ‐MoO2 (IV) complexes with calf thymus DNA was also studied using spectroscopic, and hydrodynamic techniques.