Synthesis and Crystal Structures of Mn(II) and Co(II) Complexes as Catalysts for Oxidation of Cyclohexanone

The global demand on adipic usage in the production of plasticizers and synthetic polyamide is increasing. In line with search for an efficient energy-conserving way to isolate acid (AA) good yields, this paper introduces oxidization cyclohexanone utilizing two new coordination compounds, [Mn(2,6-pydc)2](imi) (1) [Co(H2pza)2(H2O)2(NO3)].NO3 (2), as catalysts. Compounds 1 2 were synthesized by room temperature refluxing methods, characterized spectral analyses (IR UV-Vis.), SEM, BET, TGA, elemental, X-ray crystallography. single crystal structure compound revealed that pyridinedicarboxylate (2,6-pydc) imidazole (imi) moieties coordinated Mn(II) atom through imine nitrogen deprotonated oxygen atoms, form undistorted octahedral geometry N2O4 donor set. axial equatorial planes containing O2, O4, O5, O7 atoms from adjacent 2,6-pydc ligands which formed unidendate ligand; imi, other hand, acted a bidendate ligand. For 2, Co(II) was being pyrazinamide (H2pza) moieties, water molecules occupying position, one nitrate molecule apical within sphere; disordered outside sphere. distance, 4.658 Å, between Co1 N8 uncoordinated molecule, range reported elsewhere. Cyclohexanone peroxidation experiments exhibited unique catalytic performance giving 72.8% yield acid, comparison 71.3% obtained 2. yields AA maintained recyclability evaluation. reaction kinetics gave less activation energy, Ea 2938 J mol−1, while thermodynamic parameters indicated chemical reactivity active surfaces compounds via monolayer physisorption.