A novel Pyridine-2,6-dicarboxylic acid mixed ligands complex of formula [Co(NO3)2].6H2O has been obtained by the reaction of Pyridine-2,6-dicarboxylic acid with cobalt nitrate and 1,10-phenanthroline on heating in water. The structures of [Co(pydc)(Phen)(H2O)](pydcH2).4H2O receptors, and their complexes were optimized using DFT method at the B3LYP/3-21G** level. The highest occupied molecular orbital (EHOMO) and the lowest unoccupied molecular orbital (ELUMO) energies have been derived at the same level of theory. All the calculations were performed using the GAUSSIAN 03 program. The optimized geometries and frequencies of the stationary point are calculated at the B3LYPlevel of theory. The large HOMO-LUMO energy gap, both in neutral and anionic form, further provide evidence of their stability.Complex structure of the protein withamino acid groups is shown. All chemicals purchased were of reagent grade or better and were used without further purification. Manuscript profile

Compound (N,N-bis (salicylidene) 1,2-diaminophenylene) was prepared by condensation of ethanolsolution of 2-Hydroxybanzaldehyde and 1,2-diaminophenylene. The compound was characterized by1H NMR, infrared spectroscopy (FT-IR) data and analytical data. The geometrical parameters andenergies have been obtained from Density Functional Theory (DFT) B3LYP method and Hartree-Fock (HF) method with 3-21G* (6D, 7F) basis sets calculations. In the first instance, the full geometryoptimization of the studied molecule was performed at the gradient corrected density functional levelof theory using the hybrid B3LYP method based on Becke’s three parameters functional of DFT andGauge Including Atomic Orbital (GIAO). HF/3-21G* (6D, 7F) calculations on B3LYP geometrieswere done for all the reactants and HOMO-LUMO energy gaps. The force fields calculated with theB3LYP functional yield infrared spectra in very good agreement with the experiment. All of thesecalculations were performed using Gaussian 03 program. Manuscript profile