Applied coordination chemistry

Despite their crucial role in life, the trace metals make up only a tiny fraction of the human body-weight (Table 28.1). In this chapter we look at the ways in which living systems store metals, and the manner in which trace metal ions take part in the transport of molecules such as O2, electron transfer processes and catalysis. It is assumed that the reader has already studied Chapters 19 and 20, and is familiar with the general principles of J-block coordination chemistry a study of the trace metals in biological systems is applied coordination chemistry. 

Molecular mechanics calculations have become a well established tool in the area of coordination chemistry, including the coordination chemistry of nickel375-379 where they are often applied for the analysis or the prediction of structures,380 the computation of isomer or conformer ratios and metal ion selectivities,381,382 and for simulating spectroscopic properties in combination with AOM calculations or by hybrid quantum mechanics/molecular mechanics (QMMM) methods.383,384 Details of the various approaches, e.g., the incorporation of d-electron stabilization energy... 

In the broadest sense, coordination chemistry is involved in the majority of steps prior to the isolation of a pure metal because the physical properties and relative stabilities of metal compounds relate to the nature and disposition of ligands in the metal coordination spheres. This applies both to pyrometallurgy, which produces metals or intermediate products directly from the ore by use of high-temperature oxidative or reductive processes and to hydrometallurgy, which involves the processing of an ore by the dissolution, separation, purification, and precipitation of the dissolved metal by the use of aqueous solutions. 4... 

Technetium and rhenium coordination chemistry has actively developed in order to design materials as potential radiopharmaceuticals diagnostic imaging agents for technetium and potential therapeutic reagents based on rhenium. Continuous efforts are still applied to find efficient chelating systems for the [MO]3+ cores (M=Tc, Re). Thus several complexes with monodentate and... 

The stability of the polypyridyl rhenium(I) compounds mentioned above stimulated applications of this coordination chemistry. Thus, new heterotopic bis(calix[4]arene)rhenium(I) bipyridyl receptor molecules have been prepared and shown to bind a variety of anions at the upper rim and alkali metal cations at the lower rim. A cyclodextrin dimer, which was obtained by connecting two permethylated /3-cyclodextrins with a bipy ligand, was used for the preparation of a luminescent rhenium(I) complex. The system is discussed as a model conipound to study the energy transfer between active metal centers and a bound ditopic substrate. The fluorescence behavior of rhenium(I) complexes containing functionalized bipy ligands has been applied for the recognition of glucose. ... 

Organohydrazine derivatives play an important role in the coordination chemistry of rhenium since they represent important intermediates in the preparation of nitrido, imido, or dinitrogen complexes as has been described in the previous sections. They are defined as complexes which possess metal-nitrogen-nitrogen bonds, which would (strictly applied) also include dinitrogen complexes, and indeed this class has attracted considerable attention in the exploration of biological nitrogen fixation. 

Scheme 3.3-5. (L)-control maps applied to coordination chemistry for investigating the chemical reaction...

O. (2004) Synthetic metallonucleases for RNA cleavage. Curr. Opin. Chem. Biol., 8, 192. (e) Molenveld, P., Engbersen, J.F.J. and Reinhoudt, D.N. (2000) Dinuclear metallophosphodiesterase models application of calix[4]arenes as molecular scaffold. Chem. Soc. Rev., 29, 75. (f) Kimura, E. (2000) Dimetallic hydrolases and their models. Curr. Opin. Chem. Biol., 4,207. (g) Williams, N.H., Takasaki, B. and Chin, J. (1999) Structure and nuclease activity of simple dinuclear metal complexes quantitative dissection of the role of metal ions. Acc. Chem. Res., 32, 485. (h) Hegg, E.L. and Burstyn, J.N. (1998) Toward the development of metal-based synthetic nucleases and peptidases a rationale and progress report in applying the principles of coordination chemistry. Coord. Chem. Rev., 173, 133. 

The treatment has wide applicability to coordination chemistry and to other solution phenomena. For example, aspects of it have been applied by Lilley to an explanation of salting-out and salting-in phenomena (75) and to weak interactions in binary nonelectrolyte mixtures in a third solvent (76). 

This section would not be complete without a brief mention of the use of molecular mechanics calculations in coordination chemistry, as these have been applied mainly to amine complexes 46,47 While most calculations relate to complexes of Co111, these are now being extended to complexes with other metal centres, e.g. Ni11.48... 

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