Selective ligand design

This overview of MM calculations on metal complexes demonstrated the versatility and increasing utility of the MM approach in understanding steric effects in coordination chemistry. The quantitative correlation of MM results with experimentally determined reactivity parameters should encourage the further application of MM as a tool for metal-selective ligand design. As additional force field parameters for metal complexes are developed and refined, the use of MM methods for metal complexes will continue to gain in popularity. 

Bremner,. B., Coban, B., Griffith, R Groenewoud, K. M., Yates, B. F. Ligand design for alpha] adrenoceptor subtype selective antagonists. Bioorg. Med. Chem. 2000, 8, 201-214. 

The ideas presented here merely scratch the surface of factors that control metal ion selectivity in biological systems. It is hoped that in future the picture will become even clearer, enabling us to learn much more about ligand design and selective metal ion complexation. 

This review will focus on processes which depend on the selection or design of ligands to enhance the effectiveness of the four unit operations listed above. In general, the application of such ligands relates to equilibria involving distribution of a metal between two phases. 

To produce 100 000 tonnes of nonanal per year (25% down time, 100% conversion of substrate, 80% selectivity to nonanal) requires a production rate from the reactors of 19 tonne h 1, so that each batch must be 6.3 tonnes. Assuming a 1 1 ratio by volume of fluorous solventdiquid substrate and a 75 % loading, each reactor must have a volume of 20 m3. If the distillation column were fully integrated into the system it would be required to handle 19 tonnes aldehyde h 1. An increase in selectivity to the linear product, which could be achieved using careful ligand design would reduce the reactor size by up to 25%. 

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