Synthesis and characterization of molybdenum and tungsten complexes of oxindole hydrazone and DFT study

A new hydrazonoic Schiff base, (Z)-4-((3-cyano-4,6-dimethylpyridin-2-yl)amino)-N'-(2-oxoindolin-3-ylidene)benzohydrazide (H2BISH) (1) and its corresponding metal chelates; [MoO2(HBISH)2] (2) and [WO2(HBISH)2] (3) were synthesized and characterized using elemental analyses (C, H, N and M content) and spectroscopic methods, viz Infrared and UV-visible. The data indicated that ligand reacts with the metal ion in a 2:1 (L:M) molar ratio.IR and electronic spectral data revealed that H2BISH (1) behaves as monobasic bidentate chelate through the oxygen atom of the enolized (C=O) group of isatin moiety and the nitrogen atom of the hydrazonic (N-H) group in an octahedral geometry. Molecular modelling was computed by density function theory (DFT) to deduce the geometries of the prepared H2BISH ligand (1) and its meta complexes (2 &3) and evaluate other energetic parameters such as highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO). Finally, the energy gap values of the prepared ligand H2BISH (1) and its complexes (2 &3) were calculated.