Coordination compounds biological importance

Some of the important types of coordination compounds occur in biological systems (for example, heme and chlorophyll). There are also significant applications of coordination compounds that involve their use as catalysts. The formation of coordination compounds provides the basis for several techniques in analytical chemistry. Because of the relevance of this area, an understanding of the basic theories and principles of coordination chemistry is essential for work in many related fields of chemistry. In the next few chapters, an introduction will be given to the basic principles of the chemistry of coordination compounds. 

The organometallic chemistry of vanadium has been surveyed in COMC (1982) and COMC (1995).152 153 The chemical and biological importance of vanadium was reviewed in a dedicated edition of Coordination Chemistry Reviews.1 4 Relevant synthetic aspects of vanadium chemistry have also been reviewed,155-158 including early report by Hirao et al. on formation of ketones from organovanadium compounds and acid chlorides.159... 

The geometry of the coordination compounds can be similarly predicted based on the coordination number of the central atom. Coordination numbers 2 and 3 are both relatively rare and give linear and planar or pyramidal geometries, respectively. The most important coordination numbers are 4, 5 and 6 with the latter being the most important one as nearly all cations form 6-coordinate complexes. Table 2.4 shows the geometries corresponding to the commonest coordination numbers in biological systems. 

The importance of metal coordination compounds in biological systems has led to the study of polydentate Schilf base complexes of cobalt(II), nickel(II), and copper(II) (204, 205). Dimers have been observed in the spectra of complexes of both tri- and tetradentate ligands [e.g., salicylaldehydeand A,A-bis(salicylidene)ethylenediamine]. The parent ions form the base peaks, and the spectra are characterized... 

Considerable attention has been focussed upon possible amino acid prebiotic syntheses in this section, because of their biological importance. It should be pointed out that many other compounds of biological significance have also been made under simulated primitive conditions and it is proposed to conclude this review with a brief examination of such reactions, particularly with respect to the possible role of coordination compounds in them. 

Our brief review of Bersuker s academic life won t be complete, without mention to his excellent reviews and books on the Jahn-Teller effect and vibronic interactions in molecules and solids, on vibronic theory of ferroelectricity, on electron properties of coordination compounds, and on the electron-conformational approach to the problem of identification of biologically active units in a large set of molecules. However, the most important creation of Isaac Bersuker is his school, the world-known group of scholars that hold his system of views and follow his high... 

Carbohydrates are also oxygen-containing ligands [1, vol.2 554-559]. It is supposed [557] that the diol function, similar to 299, participates as a structural unit in their complexes. It is present both in mono- and dinuclear chelating complexes [557], Among these coordination compounds, the natural carbohydrate complexes [558] have been isolated in relation to their biological and medical importance (for simulation of enzymes). 

Coordination compounds play an important role in modern human life [287]. In this respect, the controlled synthesis is of paramount significant in the modeling and creation of substances with physicochemical and practical properties programmed in advance, in particular those useful in medicine and biology. The examination of this problem is beyond the limits of the present monograph, but we will examine here the most important problems, in our opinion, discussed in 1990-2002. 

It is necessary to pay attention to the fact that, during recent years, the bioinorganic properties of aluminum coordination compounds have become the objects of detailed study their general aspect [354], metabolism and toxicology [355,356], complex formation with nucleozides of di- and triphosphates and nucleo-zide-bound proteins [357], and x-ray analysis of biologically important complexes... 

The coordination compounds of the alkaline-earth metals are becoming increasingly important to many branches of chemistry and biology. A considerable degree of structural diversity exists in these compounds, and monomers up to nonametallic clusters and polymeric species are known. 

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