Mixed ligand metal-complexes of tridentate N, N, S pyrazole containing Schiff base and 2-amino-1-ethylbenzimidazole: Synthesis, structure, spectroscopic studies and quantum-chemical calculations

The synthesis of a series of adducts of 2-amino-l-ethylbenzimidazole (L-1) in Cu(II), Co(II), Zn(II) and Ni(II) chelates of the N, N, S tridentate basic form of the tosylamino functionalized pyrazol containing Schiff base N-[2-[[3-methyl-1-phenyl-5-thioxo-pyrazole-4-ylidenemethyl]amino]pheny1]-4-methylbenzene-sulfonamide (H2L) with common formula [M(L)L-1] was performed. The compounds were characterized with C, H, N elemental analysis, FT-IR, H-1 NMR, X-ray absorption spectroscopy and magnetic measurements. Crystal structure of nickel complex [Ni(L)L-1] showed that the 2-amino-l-ethylbenzimidazole co-ligand is coordinated through the endocyclic nitrogen atom of pyridine type. The assignment and the nature of the electronic transitions observed in the UV-Vis spectra of chelates were analyzed using time-dependent (TD) DFT calculations. (C) 2017 Elsevier Ltd. All rights reserved.