Two new Schiff base ligands containing ASiOCH 3 or ASiOCH 2 CH 3 groups, 4-{[(3-trimethoxysilanepropyl)imino]methyl}benzene-1,3-diol (1) Hmsb and 4-{[(3-triethoxysilanepropyl)imino]methyl}benzene-1,3-diol (5) Hesb, have been synthesized by the reaction of 2,4-dihydroxybenzaldehyde with 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane. Six new transition metal [Cu II , Ni II and Co II ] complexes of these Schiff Base ligands were prepared. The complexes are formed by coordination of N, O atoms of the ligands. Their structures were confirmed by elemental analyses, 1 H nmr, i.r. and u.v.-vis. spectral data. The analytical data shows that the metalto-ligand ratio in the Schiff Base complexes contains silane in 1:2. In addition, the antimicrobial activity of (1) Hmsb and (5) Hesb Schiff ligands, and their [M(msb) 2 ] and [M(esb) 2 ] type coordination compounds, were investigated.

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A new vicinal dioxime ligand containing azo and thione chromophores, namely 1,3-bis[4-(phenyldiazenyl)-phenyl]-2-thiooxaimidazoline-4,5-dione dioxime (bppH 2 ), was synthesized by the reaction of cyanogen di-N-oxide with N,N 0 -bis(4-phenylazophenyl) thiourea in dichloromethane solution at -10°C. Mononuclear complexes of bppH 2 with nickel(II), cobalt(II), and copper(II) were synthesized. The complexes, [Ni(bppH) 2 ], [Cu(bppH) 2 ], and [Co(bppH) 2 ] were characterized by several techniques using elemental analyses, conductivity measurements, FT-IR, and electronic spectral studies. The data suggest that the ligand coordinates through the N,N atoms, as do most vic-dioximes. The molar conductivities in DMF solution indicate nonelectrolytic nature for the complexes. Antimicrobial activities of the ligand and its metal complexes were estimated for five bacteria, namely Klebsiella pneumoniae, Micrococcus luteus, Mycobacterium smegmatis, Enterobacter cloaca and Bacillus megaterium and three fungi, namely Candida albicans, Kluyveromyces marxianus, and Rhodotorula rubra.

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