Ligand complexes, high-complexation

Colorimetric. A sensitive method for the deterrnination of small concentrations of dissolved iron is the spectrophotometric deterrnination of the orange-red tris(1,10-phenanthroline)iron (IT) complex. Other substituted phenanthrolines can be even more sensitive. Only the inon(II) complexes of these Ligands are highly colored. The sample is first treated with an excess of reducing agent. The complexes are stable from pH 2 ndash 9 and analysis preferably is done at about pH 3.5. 

The magnitude of J(Pt—P) for some phosphine-substituted SiPt complexes depends on the covalency of the Pt—P bond (136). Such a bond is relatively ionic in a system where it lies trans to a ligand of high trans influence and J(Pt—P) is then small. The coupling in cis complexes decreased in the order Cl > C > Si and since a comparable situation has been observed for methyl-Pt compounds it is suggested that the effect is one of a- rather than tr-interaction. 

It is important to emphasize that this lattice database is highly idealized compared to real databases. Unlike the lattice database, real databases cannot be treated as thermodynamic ensembles of protein-ligand complexes equilibrated at room temperature [33,34]. Two of the more straightforward reasons are mentioned here. First, real databases are inherently biased toward strong binders (K < 10 pM), because weak binders are difficult to crystallize and of lesser interest. Second, as mentioned above, real databases are not composed of a representative selection of proteins and ligands, and their compositions are biased toward peptide and peptidomimetic inhibitors and certain protein superfamilies. In contrast, because only one protein and four ligand types are used, the lattice database should have representative ligand compositions. 

In the hydroformylation of lower alkenes using a modified cobalt catalyst complex separation is achieved by distillation. The ligands are high-boiling so that they remain with the heavy ends when these are removed from the alcohol product. Distillation is not possible when higher alcohols or aldehydes are produced, because of decomposition of the catalyst ligands at the higher temperatures required. Rhodium complexes can usually also be removed by distillation, since these complexes are relatively stable. 

Once a structure of the desired protein has been solved, it is a very rapid process to produce subsequent high-quality structures and, in fact, some groups have even linked various scripts together, or modified software tools to provide much more automated software aids to repeated crystal structure solution, such as when solving multiple ligand complexes of the same protein [7]. 

Dithiolene complexes with the maleonitriledithiolate (mnt) ligand form highly delocalized systems and are widespread in studies of conducting and magnetic materials. The electronic properties have been extensively studied with various computational methods including Hiickel and extended Hiickel approaches to identify the nature of the orbitals involved in intramolecular and intermolecular interactions. These structural properties allow the complexes to interact in the solid state via short stacking S, S and short interstack S---S contacts.10 4-1048... 

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