Recent Progress of Dinuclear Organotin (IV) Complexes with Bis-hydrazones

In coordination chemistry, interest in the use of hydrazones as polyfunctional ligands has increased considerably. Acyl/aroyl hydrazones with the C=NNHC(O) functional group are a particular category of hydrazones. Among these derivatives, the chemistry of bis acyl/aroyl-hydrazones is seen to be of particular interest due to the possibility of creating various types of coordination modes. The flexibility of distance introduced between two coordinating units of these bifunctional hydrazones may result in interesting structural or reactivity features in the ligand and its metal complexes. Recently, the synthesis and structural investigation of binuclear organotin(IV) complexes of bis-hydrazones have received attention and we have also published several articles in this area [1-3]. Research into the organotin(IV) chemistry is a prolific area of chemical investigations. These compounds have found more industrial, agricultural and medicinal applications than any other organometallic compounds. In addition, they present an interesting structural variety, so that structural studies have always been prominent in organotin(IV) chemistry. Among these studies, the inclusion of two organotin units, instead of just one, in the same molecular entity may produce compounds with interesting biological and structural properties. As a part of our investigation dealing with the study of organotin(IV) complexes, we review the synthesis, structural chemistry and biological properties of binuclear organotin(IV) complexes with several bis-hydrazones. In most of these complexes, the dihydrazone ligand was symmetric and both tin atoms were in the same chemical environments, while in some others bis-hydrazone is asymmetric or contains two different donor environments. This is readily proven by observing one or two signal in 119Sn NMR spectrum of the complex. Also, The X-ray crystallographic structures, in vitro antibacterial activity, interaction with DNA and in vitro cytotoxicities of some synthesized ligands and their complexes will be described.