الفهرس 
Synthesis of metal complexes of Schiff basesOnly 14 pages are availabe for public view
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Abstract
Compound with the general structure R2C=NR’ (R’ ≠ H) can be considered a sub-class of imines, being either secondary ketimines or secondary aldimines depending on their structure [1]. A number of special naming systems exist for these compounds [2]. For instance a Schiff-base derived from an aniline, where R is a phenyl or a substituted phenyl, can be called an anil [3], while bis-compounds are often referred to as salen-type compounds. The term of Schiff base is normally applied to these compounds when they are being used as ligands to form coordination complexes with metal ions. Such complexes do occur naturally, but the majority of Schiff-bases are artificial and are used to form many important catalysts, such as Jacobsen’s catalyst
Different Schiff-bases and their metal complexes had shown notable bioactivity as chelating therapeutics, as drugs and as inhibitors of enzymes [4]. Also, some Schiff-bases acted as an important analytical reagents for the gravimetric and colorimetric determination of transition metals [5]. The presence of Cu(II) ion in these complexes had received wide interest in the fields of the magneto-structural relationship and the characterization of active sites in multicopper proteins [6]. Cu(II) complexes had a wide range of biological activity and some of these complexes had been known to be antitumor, antiviral, and anti-inflammatory agents. In addition to Cu(II) complexes especially with Schiff-base ligands were models of physical and chemical behavior of biological copper systems, considerable attention had been focused on these compounds [1,7] . The Cu(II) complex of 1, 10-phenathroline was the first synthetic transition metal complex effectively exhibiting nucleolytic activity.
The development of Schiff-base species based on transition metal compounds and polydentate ligands had been the subject of extensive research due to their potential applications in materials science [5], environmental chemistry and medicine. Schiff-base compounds played a vital role in coordination chemistry are due to their ability to react with a range of metal ions forming stable complexes which had applications in different fields. One interesting application in the field of coordination chemistry had been to investigate the use of Schiff-base ligands to develop phenoxo-bridged binuclear complexes with homometallic and heterometallic centres. This included design molecules containing paramagnetic metal centers were able to self-assemblethrough metal-ligand interactions rendering supramolecular assemblies with interesting structural and magnetic properties [8,9]. Schiff-base metal complexes also had applications in biomedical [10, 11], biomimetic and catalytic systems The role of Schiff-base and their metal complexes, in particular cobalt, in the biological systems make them one interested branch in the coordination and organometallic chemistry. Significant publications dealt with the development of coordination chemistry were related to the preparation and characterization of Schiffbase and their metal complexes. These included the investigation of synthetic methods and coordination modes of Schiff-base species upon complexation [14]. It was well known that, Schiffbase species can bind a metal in different coordination modes [15]. The mode of bonding was investigated through physico-chemical and spectroscopic methods. X–ray crystal structures confirmed the preparation of six-coordinate Schiff-base complexes. It was well documented that, Schiffbase compounds and their complexes with transition metals had many applications in medicine, biology, industry, and catalysis [16]. The chemistry of Schiff-base complexes had been broadly investigated [17]. Particularly in Cu(II) and Ni(II) complexes with Schiff-base ligands The coordination chemistry of the Schiff-base ligands had been widely studied with the 3d metal ions [20, 21]. The Schiff-base imines of ligands capable of withstand higher oxidation states of the central metal ion through strong ligand to metal [L-M] σ - donation. The strength of the hydrogen bond in Schiff-base depends on the size and chemical environment around the metal ion.