Arpan Dutta

Copper(II) induced oxidative modification and complexation of a schiff base ligand: synthesis, crystal structure, catalytic oxidation of aromatic hydrocarbons and DFT calculation

A mononuclear square planar complex [CuII(Lf)] (1) was synthesized and structurally characterized by single crystal X-ray diffraction studies. Though we have started with the Schiff base H2La with two –CH2OH groups for complexation with Cu2+, the final product appears to have two formyl groups where two carbinols were oxidized during the course of the reaction with Cu2+. It opens up the possibility of using this complex as a precursor for condensation with suitable amines to give symmetric/asymmetric cyclic/acyclic Schiff base complexes. Systematic studies on catalytic oxidation of aromatic hydrocarbons like toluene and xylenes by an environmentally benign oxidant, H2O2 in the presence of 1 as a catalyst reveals that it is an efficient catalyst leading to the formation of the corresponding alcohol as the major product with TON ∼300 and alcohol selectivity of ∼72%.

Mononuclear manganese(III) complexes of bidentate NO donor Schiff base ligands: synthesis, structural characterization, magnetic and catecholase studies

We have synthesized four mononuclear manganese(III) complexes (1–4) of four closely related bidentate NO donor Schiff-base ligands, out of which three (2–4) were structurally characterized. Crystal structure determination reveals that all these complexes are in octahedral geometries. Magnetic studies have been carried out on complexes 2, 3 and 4 in the temperature range 2–300 K under a magnetic field of 0.1 T which yielded negative ZFS parameters of −2.96, –3.51 and −3.72 cm−1 respectively. The catecholase activities of complexes 1–4 have been investigated following the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butylbenzoquinone (3,5-DTBQ) with molecular oxygen in DCM at 25 °C, which were found to follow the Michalis–Menton type relation giving the highest TON (Kcat) for the so far reported Mn(III) complexes.