Nickel(III) Complex Derived from 2-Hydroxy-3-Methoxybenzaldehyde Semicarbazone and 2,2’-Bipyridine

Abstract

Abstract. Reaction of 2-hydroxy-3-methoxybenzaldehyde semicarbazone with Ni(NO 3 ) 2 ·6H 2 O, in the presence of 2,2'-bipyridine, afforded a dinuclear complex (1). Crystal structure of 1 revealed the dinuclear complex, in which one nickel center is surrounded octahedrally by two monoanionic O,N,O-donor semicarbazone. The second nickel center also adopts an octahedral geometry created by two 2,2'-bipyridine ligands and the bridging phenolate oxygen of the monodeprotonated semicarbazones.Keywords: semicarbazone, binuclear nickel(II) complex, crystal structure. IntroductionChemistry and pharmacological applications of semicarbazones have been extensively investigated due to their wide range of biological activities, such as antitumoral, antibacterial, antiviral and antimalarial effects [1,2]. By coordination to a metal ion, the biological properties of semicarbazones are often modifi ed: lipophilicity, increasing of activity, decreasing of side effects, reduction of drug-resistance. Tridentate ONO Schiff base, obtained by condensation of salicylaldehyde with semicarbazide has been used for the synthesis of a large variety of synthesis of mononuclear complexes and multinuclear clusters of transition metals, such as Cu(II) [3][4][5][6][7], Cr(III) [8], Co(III) [9], as well as dioxovanadium(V) [10] complexes. A dinuclear zinc(II) complex with salicylaldehyde semicarbazone was prepared and structurally characterized, where the deprotonated phenol group of the ligand forms a bridge between the two zinc centers [11]. Additional coordinating groups attached to salicylaldehyde would increase both the denticity of the resulted Schiff bases, and as result the ability to generate polynuclear complexes. 2-Hydroxy-3-methoxybenzaldehyde was largely employed as carbonyl precursor for the synthesis of multimetallic assemblies due to ability of metoxy group to display a variety of bonding geometries, such as chelating, monodentate/bidentate bridging, and chelating bridging [12][13][14]. The Schiff base ligand, 2-hydroxy-3-methoxybenzaldehyde semicarbazone (H 2 L, Figure 1) has been used to synthesize monomeric vanadium(V) and dimeric palladium complexes [15][16]. The structure of H 2 L has been reported in [17].

Structure and Some Biological Properties of Fe(III) Complexes with Nitrogen-Containing Ligands

“…The complex is well soluble in methanol and DMF, less soluble in water and diethyl ether. Yield-80% [13].…”

“…The literature, in the last decades, denotes high physiological activity of the coordination compounds of transition metals on biological objects, including microorganisms [1][2][3][4][5][6][7][8][9][10][11][12][13]. Some authors note a signifi cant role of these compounds in the directed synthesis of biologically active substances from microalgae and cyanobacteria, fi lamentous fungi and yeast [1][2][3][4][5][6][7][8][9][10]12].…”