Potential ligand for

Many substitution reactions occur between metal carbonyls and other potential ligands. For example,... 

Prior to their work with the Strecker reaction the Jacobsen group reported a combinatorial approach to the discovery of coordination complexes (29). A modular approach was taken in the synthesis of libraries of potential ligands for transition metals. Four variable components were used. Two amino acids were placed at positions 1 and 2, with a turn element connecting these groups (Scheme 9). The... 

F. Wust, J.M.H.M. ReuI, T. Rein, A. Abel, G. Stocklin, PET-corticosteroids as potential ligands for mapping brain glucocorticoid receptors (GR), J. Label. Compds Radiopharm. 44 (2001) S12-S14. 

F. Wust, K.E. Carlson, J.A. Katzenellenbogen, Synthesis of novel arylpyrazolo corticosteroids as potential ligands for imaging brain glucocorticoid receptors. Steroids 68 (2003) 177-191. 

H. Luo, A. Hasan, V. Sood, R.C. McRee, B. Zeeberg, R.C. Reba, D.W. McPherson, F.F. Knapp Jr, Evaluation of 1-azabicyclo[2.2.2]oct-3-yl ot-fluoroalkyl-a-hydroxy-a-phenylacetates as potential ligands for the study of muscarinic receptor density by positron emission tomography, Nucl. Med. Biol. 23 (1996) 267-276. 

Aicher B, Lerch MM, Muller T et al (1997) Cellular redistribution of protein tyrosine phosphatases LAR and PTPa by inducible proteolytic processing. J Cell Biol 138 681-96 Alete DE, Weeks ME, Hovanession AG et al (2006) Cell surface nucleolin on developing muscle is a potential ligand for the axonal receptor protein tyrosine phosphatase-cr. FEBS J 273 4668-81 Andrade MA, Perez-Iratxeta C, Ponting CP (2001) Protein repeats structures, functions, and evolution. J Struct Biol 134 117-31... 

Brugel, T.A. and Hegedus, L.S. (2003) N-functionalization of poly(ethylene glycol)-linked mono- and bis-dioxocyclams as potential ligands for Gd3 +. Journal of Organic Chemistry, 68, 8409—8415. 

VLDL=very low density lipoproteins LDL=low density lipoproteins substances such as fibrin in blood clots (i.e. potential ligands for targeting of fibrinolytics). 

Disproportionation reactions. Metal carbonyls undergo disproportionation reactions in the presence of other potential ligands. For example, in the presence of amines, Fe(CO)5 reacts as follows ... 

In the presence of potential ligands for lithium, f-butyllithium was found to be a dimer in diethyl ether-<7 0, a mixture of dimers and monomers in TIIIw7 0 and entirely monomeric when complexed to PMDTA. All these results are derived from one bond 13C—6Li coupling patterns in 13C NMR spectra, needless to say with NMR determined at low temperature, >160 K, since the reagent rapidly deprotonates all these ligands at higher temperatures. 

The large size of transferrins (670-700 residues), with the consequent difficulties of chemical sequencing, meant that it was not until 1982 that the first amino acid sequences, those of human serum transferrin 10) and chicken ovotransferrin 34,35), were established. These were closely followed by that of human lactoferrin 11). The twofold internal repeat in each sequence (see below) was immediately apparent, and comparison of all three sequences then identified conserved tyrosines and histidines that were potential ligands for iron (11). 

Figure 4. Synthesis of amino alcohols on a solid phase as potential ligands for the addition of diethylzinc to aldehydes.

Figure 5. Synthesis of a peptide library with phosphine-containing amino acids as potential ligands for the asymmetric hydrogenation.

Linking stacks together can be achieved by incorporating ligands with pendant arms into the first stack, which are themselves potential ligands, for example (34). One of the results of this strategy is the formation of (21). 

Bolm, C. Muniz, K. Planar Chiral Arene Chromium (0) Complexes Potential Ligands for Asymmetric Catalysis, Chem. Soc. Rev. 1999, 28, 51-59. 

Because of their basic resemblance to porphyrins, it was initially expected that the sapphyrins would mimic, at least on some level, the rich coordination chemistry displayed by the porphyrins. However, the larger core size ca. 5.5 A inner N-N diameter vs. ca. 4.0 A for porphyrins), the greater number of potentially chelating heteroatom centers, and the fact that pentaazasapphyrins when fully deprotonated are potentially trianionic ligands made sapphyrin a likely candidate for large metal chelation, particularly as a potential ligand for the trivalent lanthanides and actinides. Unfortunately, in spite of extensive effort, this hope remains largely unrealized. Nonetheless, some metal complexes of sapphyrins and heterosapphyrins have been successfully prepared and characterized. Their preparation and properties are reviewed in this section. 

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