Bis‐dioxomolybdenum (VI) oxalyldihydrazone complexes: Synthesis, characterization, DFT studies, catalytic epoxidation potential, molecular modeling and biological evaluations

Abstract

Two cis‐bis‐dioxomolybdenum oxalylsalicylidenedihydrazone complexes (MoO2L1 and MoO2L2) were synthesized via the complexation of dioxomolybdenum (VI) acetylacetonate with oxalylsalicylidenedihydrazone (H2L1) and p‐sodium sulfonate oxalylsalicylidenedihydrazone (H2L2) bis‐Schiff base chelating ligands, respectively. The structures of the newly synthesized complexes were confirmed by 1H‐ and 13C‐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 °C. Under aqueous conditions, the MoO2L2 (with p‐sodium sulfonate substituent) exhibited superior that of the MoO2L1 (without p‐NaSO3―group), highlighting the role of sodium sulfonate substituent in the catalytic progress of the Mo‐chelate. The ligands (H2L1 and H2L2) and their corresponding Mo‐complexes (MoO2L1 and MoO2L2) 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.

Light-Initiated C–H Activation via Net Hydrogen Atom Transfer to a Molybdenum(VI) Dioxo

“…Density functional theory computations were performed to probe the frontier orbital composition and the lowest-energy electronic excitations using the Gaussian 16W software suite, the restricted Becke three-parameter Lee–Yang–Parr (rB3LYP) functional, Def2TZVP for Mo, and 6–311G+(d,p) for nonmetal atoms. The geometry of 1 was optimized in conductor-like polarizable continuum solvent model (CPCM) for CH 3 CN . The computed highest occupied molecular orbital (HOMO) of this structure (Figure ) is localized on the bpy- t Bu ligand (>99% contribution of bpy- t Bu), while the lowest unoccupied molecular orbital (LUMO) is a Mo-based orbital (60% Mo d yz , 20% O, 15% Cl, 7% bpy- t Bu) with π* interactions to the O atoms and σ* interactions to the Cl atoms.…”

“…The geometry of 1 was optimized in conductor-like polarizable continuum solvent model (CPCM) for CH 3 CN. 90 The computed highest occupied molecular orbital (HOMO) of this structure (Figure 9) is localized on the bpy- S14) identified as an LMCT, indicating that the accessible excited state supports a transiently reduced Mo center with radical cation character on the bpy-t Bu ligand.…”

Synthesis, structural identification, DNA interaction and biological studies of divalent Mn, Co and Ni chelates of 3‐amino‐5‐mercapto‐1,2,4‐triazole azo ligand

“…Ni (II) complex C3 represented two absorption peaks at 18519 and 20243 cm −1 due to 3 A 2g ! 3 T 1g (P) and 3 A 2g ! 3 T 1g (F) transitions, successively, confirming the octahedral configuration around nickel (II) complex.…”

“…Thus, in recent years, investigation of the interaction between transition metal chelates and DNA (deoxyribonucleic acid) have been pursued. [3][4][5] Azo dye ligands and their metal chelates are wellrenowned to be included in a number of biological reactions, such as inhibition of DNA, RNA, and protein synthesis, nitrogen fixation, and carcinogenesis. [6] The azo dye chelates have received much attention due to their versatile use in many technical applications such as dyeing [7,8] printing systems [9,10] as well as in catalysis.…”

New bis[cis-{MoO2}] complexes with dihydrazone ligands: synthesis, characterization, theoretical investigation and their peroxidase mimicking activity

“…Our strong desire to learn more about the chemistry of molybdenum drives us to create bis-dioxidomolybdenum complexes and determine their functionality. Previously, ligands based on dihydrazone 31 and semicarbazide 32 were developed and used to generate bis-[MoO 2 ] 2+ complexes. In this case, we have chosen Schiff base ligands with two pockets full of ONO donor atoms, which can be coordinated with metal centers to produce binuclear dioxidomolybdenum( vi ) complexes (Scheme 1).…”