Metal (II) complex of thiophene-2-carboxylic acid Hydrazide (TCH) ligand of the type [M(TCH) 2 X 2 ] where M= Mn(II), Co(II), Ni(II),Cu(II), Zn(II) and Cd(II) , X=Cl-, NO 3 have been prepared and characterized by metal analysis, molar conductance, magnetic moment measurements and electronic and IR spectral data. Based on physico-chemical studies, an octahedral geometry was assigned for all the complexes and the ligand (TCH) acted as neutral bidentate ligand, coordinating via the carbonyl oxygen and the amino nitrogen atoms.

New α-(2-pyridyl)benzylidine (5-nitropyrid-2-yl)amine (L) ligand has been synthesized by condensation of 2-benzoyl pyridine and 2-amino-5-nitro pyridine in 1:1 molar ratio in ethanol. Further the Co +2 ,Ni +2 and Cu +2 complexes were synthesized by reacting above ligand with metal chloride in (1:1) (1:2) or (2:2) (Ligand:metal) molar ratio in ethanolic medium. The ligand and their complexes were characterized by electronic and IR spectra, magnetic susceptibility measurements, molar conductance and metal content analysis. The complexes (1-3) and (7-9) are found to be non ionic in nature while the complexes (4-6) are found to be (1:2) electrolyte. The magnetic moment and electronic spectral studies show a tetrahedral geometries for the complexes (1-6) and octahedral geometries for the rest of the complexes.

Three types of Metal(II) complexes with hydrazone derived from condensation of thiophene-2-carboxylic acid hydrazide and 2-furaldehyde namely 2-furaldehyde-2thenoylhydrazone (fth) of the general formulas [M (fth-H) 2 ],[M(fth) 2 Cl 2 ] and [M(fth) 2 ] (NO 3) 2 , where M= Co(II), Ni(II), Cu(II), and Zn(II), were synthesized and characterized on the basis of elemental analysis, molar conductance, magnetic moment, infrared and electronic spectral data. The infrared and molar conductance data of the complexes reveal the monobasic tridentate ONO nature of the ligand and coordination through the enolate oxygen, furan ring oxygen and azomethine nitrogen atoms, in the complexes [M(fth-H 2)] upon deprotonation of the ligand. The same ligand acts as neutral bidentate ON in the chloro-complexes coordinated through the carbonyl oxygen and azomethine nitrogen atoms and neutral tridentate ONO in the nitrate complexes coordination through carbonyl oxygen and furan ring oxygen atoms in addition to the azomethine nitrogen atom. The magnetic and electronic spectral data suggested an octahedral geometry for the complexes.