Coordination Chemistry In Chemistry

1.1. Introduction:

Coordination chemistry is exactly it is, the chemistry of metal atoms "coordinated" by molecules and atoms. Coordination chemistry has always been a challenging task to the inorganic chemist. In the recent days of chemistry this seemed unusual (the name complexes) to define the usual rules of valency. But now-a-days this compramise a large body of current inorganic research. A survey of various articles is recent issues of journal Inorganic chemistry indicates that perhaps 70% could be considered to deal with coordination compounds. The usual bonding theories can be extended to accommodate these compounds, but this still provides many stimulating problems which have to get resolved. But in synthetic work, this continues

It was found that substances would change their properties under certain external conditions, and this observation is a characteristic of various chemical reactions involved. For example, the ancient Egyptians found that if malachite, a green ore, was burnt with charcoal, a red metal was obtained, called copper. Medicinal application of many metals can be traced back to almost 5000 years [1]. The development of modern medicinal inorganic chemistry has stimulated the discovery of cis dichlorodiammine platinum (II) [cisplatin] and its subsequent usage as a drug in treatment of several human tumors [2,3], has facilitated the inorganic chemist's knowledge on coordination and redox properties of metal ions. The positively charged metal centers, bind to negatively charged bimolecules and the constituents of proteins and nucleic acids offer as excellent ligands for binding to these metal ions. The metal complexes hence has excellent potential in pharmaceutical

Some of the side effects may be reduced by coordination, the lipophilicity which controls the rate of entry into cell, is modified[25-26]. Thiosemicarbazones may block DNA synthesis in mammalian cells by inhibiting the enzyme, ribo-nucleoside diphosphate reductase either by chelation with an iron ion required by the enzyme or because a preformed metal chelate of the inhibitor interacts with the target enzyme [27-28]. The study also show the ability of thiosemicarbazones to severe the DNA strands [29]. A major clinical challenge in treatment of cancer with anticancer drugs is that few tumour cells develop a particular phenotype, known as multi drug resistance (MDR), which transform or convert these cells resistant to other classes of anticancer agents to which the tumor cells have not been treated earlier[30]. Synthesis and characterization of a palladium complex of phenathrenequinone thiosemicarbazone and evaluation of its antiproliferative properties on breast cancer cells and normal cells have been described