Molecular ligand

Ordinarily, the names of molecular ligands are unchanged. Two important exceptions are H20 aqua NH3 ammine... 

Once in the serum, aluminium can be transported bound to transferrin, and also to albumin and low-molecular ligands such as citrate. However, the transferrrin-aluminium complex will be able to enter cells via the transferrin-transferrin-receptor pathway (see Chapter 8). Within the acidic environment of the endosome, we assume that aluminium would be released from transferrin, but how it exits from this compartment remains unknown. Once in the cytosol of the cell, aluminium is unlikely to be readily incorporated into the iron storage protein ferritin, since this requires redox cycling between Fe2+ and Fe3+ (see Chapter 19). Studies of the subcellular distribution of aluminium in various cell lines and animal models have shown that the majority accumulates in the mitochondria, where it can interfere with calcium homeostasis. Once in the circulation, there seems little doubt that aluminium can cross the blood-brain barrier. 

The data obtained in quantitative studies of these equilibria have been summarized in a review (23). These equilibria can easily be shifted in the desired direction by changing the concentrations of molecular ligands, the nature of the solvent, or the temperature. The coordination of additional ligands is accompanied by a shift of... 

In this communication we have reported the synthesis and characterization of different types of surface modified MCM-41 type pure-silicate and alumino-silicate materials. Simultaneous incorporation of thio- and amino-propyl groups was also achieved. There is tremendous potential in this field as these materials itself can be used as supra-molecular ligand in complexation with a metal ion. They can also be potentially used as host for different nano-cluster stabilization. 

We wished to develop a macroscopic model of the interactions between molecular ligands and receptors. Molecular recognition is a broad subject that describes selective assembly in chemistry and biology, with examples from DNA-protein complex formation to asymmetric catalysis. The principle behind molecular recognition dictates that the molecules that mate have complementary shapes and interfacial characteristics. Our extension of this principle to the mesoscale involved the self-assembly of objects that matched both... 

Homogeneous catalysis with macro-molecular ligands... 

The metal porphyrin in the polymer ligand was used to investigate the modified situation in comparison with a low molecular ligand by... 

Remarkable, the formation constant of porphyrin complexes with polymer ligands are 10 till 10 times higher than with low molecular ligands -This was explained by a higher concentration of the ligand now fixed in the polymer domaine. 

With spin labelled (7b) the metal chelate coordinated by polymer ligands in toluene or in the solid state shows lower ESR movement than the chelates coordinated by low molecular ligand. So the p< sibility of dimer-dimer-interaction during oxygenation leading to irreversible oxidation is reduced. Aggregates of (7a)-pyridine complexes dis-... 

Figure 6. The geminate trap of small molecular ligands bordered by Leu29, Val68 and Ilel07.

With knowledge of the discussion about the site of the - biphasic - action (interfacial conversion versus reaction in the bulk of the liquid [130, 216]) the aqueous phase hydroformylation of higher ( heavier ) alkenes is still much investigated (e. g.. Refs. [216 b, 217 a, 218 g, 219 f, h, 231]). There is a certain trend to recommend high-molecular ligands for this purpose (e. g., calix[4]arenes, dextrins, etc.). Other papers describe the hydroformylation of special alkenes using Co or Ru catalysts [232]. 

Kutsenko AS, Kuznetsov DA, Poroikov VV, Tumanian VG. Mapping of active site of alcohol dehydrogenase with low-molecular ligands. Bioorg Khim 2000 26 179-86. 

The final type of aqueous ionic equilibrium we consider involves a different kind of ion than we ve examined up to now. A simple ion, such as Na" " or S04 , consists of one or a few bound atoms, with an excess or deficit of electrons. A complex ion consists of a central metal ion covalently bonded to two or more anions or molecules, called ligands. Hydroxide, chloride, and cyanide ions are some ionic ligands water, carbon monoxide, and ammonia are some molecular ligands. In the complex ion Cr(NH3)6, for example, Cr is the central metal ion and six NH3 molecules are the ligands, giving an overall 3-1- charge (Figure 19.13). 

M. von Korff, M. Steger, GPCR-tailored pharmacophore pattern recognition of small molecular ligands,/. Chem. Inf. Comput. Sci. 2004, 44,1137-1147. 

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