Square planar versus square pyramidal copper(II) complexes containing N3O moiety: Synthesis, structural characterization, kinetic and catalytic mimicking activity

Tuning the structural and catalytic properties of copper(II)-based complexes containing pyridine-2,6-diimines

Four mononuclear penta coordinated copper(II) chelates, [CuLⁿBr₂] nH₂O, containing the tridentate neutral ligands, pyridine-2,6-diimine (Lⁿ), were prepared via the template technique. Analytical and several physicochemical methods have been used to characterize the prepared metal chelates. Square-pyramidal stereochemistry was described to the current copper(II) complexes. DFT technique has been applied to optimize the structure of the running diimines and their corresponding copper-based compounds. Ligand substitution study performed to link the catalytic potency of the candidate oxidase mimics and their lability characters. Spectral investigations reveal that nature of substituents of the chelated ligands effectively tuning the Lewis acidity of copper(II) centers. Biomimetics of redox proteins specifically containing copper were examined towards the aerobic oxidation of polyphenol. Kinetic studies with the stopped-follow technique showed a close association between the Lewis acidity of the copper(II) nuclei of the prepared chelates and their oxidase-like activity. The catalytic activity of the natural enzyme (catechol oxidase from sweet potatoes) measured and compared with that for the present Cu^II chelates. The thermodynamic parameter drive force (ΔG° or λ) of the performed oxidation processes was determined from the values of redox potential of the chemical species involved in these catalytic reactions. The proposed catalytic reactions pathways have been discussed based on the outcomes of the kinetic investigations.Communicated by Ramaswamy H. Sarma.

The effect of structural configuration on the DNA binding and in vitro antioxidant properties of new copper(ii) N2O2 Schiff base complexes

DNA interaction with cis and trans-copper NO complexes favours the cis configuration due to low energies observed in the cis configuration.

Mononuclear copper(ii) Schiff base complexes as effective models for phenoxazinone synthase

Copper(ii) complexes of tridentate (N2O) Schiff base ligands as efficient catalysts for 2-aminophenol oxidation to 2-aminophenoxazin-3-one with excellent reaction rates.

Synthesis and spectroscopic characterization of ternary copper(ii) complexes containing nitrogen and oxygen donors as functional mimics of catechol oxidase and phenoxazinone synthase

Two ternary copper(ii) complexes 1 [(Cu₂Me₄en)₄(EDTA)] and 2 [(CuMe₄en)₂(MIDA)] containing the mixed ligand system of 1,1′,4,4′-tetramethylethylenediamine (Me₄en) (L) and N-methyliminodiacetic (MIDAH₂) (L′) or ethylenediaminetetraacetic acid (EDTAH₄) (L′) were synthesized.