S-allyl-3-(2-pyridyl-methylene)dithiocarbazate ligand and its manganese(II), cobalt(III) and nickel(II) complexes

A new NNS tridentate ligand, S-allyl-3-(2-pyridyl-methylene)dithiocarbazate (HL) has been prepared. Three coordination complexes, Mn(L)2 (1), [Co(L)2]NO3 (2) and Ni(L)2 (3) (L− is the deprotonated monoanionic form of HL) have been synthesized and characterized by elemental analysis, molar conductivity, FT-IR, 1H NMR and UV–Vis spectroscopy. 1 and 3 are neutral complexes, while 2 is cationic with nitrate as the counter ion. Single crystal X-ray diffraction analysis shows that bis-chelate complexes have a distorted octahedral geometry in which two ligands in thiolate tautomeric form coordinate to the metal center through N atoms of the pyridine and imino moieties and one S atom. Molecular geometry from X-ray analysis, molecular geometry optimization, atomic charges distribution and bond analysis of the ligand and complexes have been performed using the density functional theory (DFT) with the B3LYP functional.

Graphical abstractA new NNS tridentate ligand, S-allyl-3-(2-pyridyl-methylene)dithiocarbazate (HL) and its Mn(L)2, [Co(L)2]NO3 and Ni(L)2 complexes have been prepared and characterized with usual methods. Single crystal X-ray analysis shows that bis-chelate complexes have a distorted octahedral geometry. Molecular geometry optimization, atomic charges distribution and bond analysis of the ligand and complexes have been performed using DFT with the B3LYP functional.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A new S-allyl dithiocarbazate (SNN) ligand and its some complexes were synthesized. ► All compounds are studied by IR, 1H NMR, UV/Vis and CHNS. ► Single crystal X-ray of complexes showed that they have distorted octahedral geometry. ► The ligand and Mn- and Ni-complexes have been studied by DFT/B3LYP functional.