Metal complexes of N'-(2-hydroxy-5-phenyldiazenyl) benzylideneisonicotinohydrazide: Synthesis, spectroscopic characterization and antimicrobial activity

A new series of Cu(II), Ni(II), Co(II), Mn(II), Zn(II), Cd(II), Hg(II) , VO(II), UO2(II) , Fe(III) and Ru(III) complexes of N'-(2-hydroxy-5- phenyldiazenyl)benzylideneisonicotinohydrazide(H2L) have been synthesized and characterized by elemental,1H-NMR, IR, UV-Vis., ESR, magnetic, thermogravimetric analyses(TG) and conductivity measurements. The spectral data show that, the ligand behaves as a neutral bidentate, (2), (4), (5), (6) and (14), monobasic bidentate, (3), (7), (8), (9) and (10), monobasic tridentate (11) and (16) or dibasic tridentate (12), (13) and (15) bonded to metal ions via the carbonyl oxygen atom in ketonic or enolic form, azomethine nitrogen atom and/or deprotonated phenolic hydroxyl oxygen. The ESR spectrum of solid vanadyl(II), complex (2) shows axially anisotropic spectrum with eight lines in the low field region and g?>g||, A||>>A?relationship, which is characteristics of distorted octahedral structure with dxy ground state. However, copper(II) complexes (4), (5) and (6) and manganese(II) complex (10) show an isotropic type while the copper(II) complexes (3) and (7)show an axial symmetry type with g||>g?>ge indicating a covalent bond character. The antibacterial and antifungal activities of the ligand and its metal complexes show mild activity compared with standard drugs (Tetracycline for bacteria and amphotricene B for fungi).