Modification of Ligands

These results strongly indicated that the minimum requirements for the ligand were two amides and one nitrogen atom on picoline. However, the real active Mo catalyst is not clear. 

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Modification of ligand properties (affinity, agonist, or antagonist character) toward amino acid receptors (e.g., excitatory amino acid receptors). 

The toxic action of NO has an important role, especially in nerve systems. It is assumed that during a stroke, for example, excess production of NO leads to death of nerve cells. Direct modification of ligand-gated ion chaimels, such as the receptor for N-methyl-D-aspartate (NMDA receptor), by NO has a special role in coimection with this. 

This synthetic method includes various chemical reactions of ligands and allows us to obtain new coordination compounds of many types on the basis of metal complexes. It became known long ago [2,314a,319,320] as an integral part of template synthesis and at present is examined as one of its variants [318]. Modification of ligands is the most important part of the problem of the reaction capacity of coordination compounds [130,320,321]. 

Among other template transformations, related to modification of ligand systems, it is necessary to indicate reactions of deoxygenation of sulfoxide complexes, for instance (3.195) [417] ... 

Modification of ligand systems in azine complexes was studied for the example of reactions (3.223) of r 6-coordinated 2,4,6-collidinechromiumtricarbonyl 773 (L = CO) [294] and its monotriphenylphosphine derivative 773 (L = PPh3) [492] with Lewis acids (AlBr3, SnCl4 TiCl4), leading to binuclear structures 774 ... 

The Lehn group synthesised the trinuclear copper(I) complex of the substituted 2,2 -bipyridyl/ether derivative 29 and confirmed its helical structure by X-ray diffraction (Figure 6.15). A dinuclear copper(I) complex of 30 (Figure 6.15) was also synthesised and subsequently the corresponding dimeric ethane-bridged bipyridine and phenanthroline ligands were also demonstrated to yield similar di-helicate copper(I) species. These results thus indicate that helicate formation is tolerant towards minor modification of ligand structure. ... 

These linear-chain metal complexes have been used as textbook examples to understand the basic nature of one-dimensional conductors, such as the validity of tight-binding calculations, the effectiveness of chemical modifications of ligands, the phase control by ion doping, and so on. 

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