Ligand flexibility ligands

Besides rigid ligands, flexible ligands can also be used to obtain zigzag chains. Figure 6(a) shows how the flexibility of l,6-di(friazole-l-yl-methyl)-4-methylphenol (L22) allows for its cis conformation and induces the formation... 

R and M M Hann 2000. The In Silico World of Virtual Libraries. Drug Discovery Today 5 326-336. R and I D Kuntz 1990. Conformational Analysis of Flexible Ligands in Macromolecular eptor Sites. Journal of Computational Chemistry 13 730-748. 

C M, 1D Kuntz and J S Dixon 1995. Flexible Ligand Docking Using a Genetic Algorithm. Journal Zomputer-Aided Molecular Design 9 113-130. 

DM Lorber, BK Shoichet. Flexible ligand docking using conformational ensembles. Protein Sci 7 938-950, 1998. 

The flexible ligand (731) forms stable dinickel(II) complexes both in solution and in the solid state. The crystal structure of [Ni2(731)Cl3] reveals the bridging phenolato-O, a secondary Cl bridge, and two terminal Cl ligands, i.e., six-coordinate metal ions.1885... 

A number of mixed crown ligands have been synthesized combining N, O, or S ligands. The larger, more flexible, ligand systems can show interesting coordination patterns as the zinc binds to its preferred donor set. 

Mills JEJ, De Esch IJP, Perkins TDJ, Dean PM. SLATE a method for the superposition of flexible ligands. J Corn-put Aided Mol Design 2001 15 81-96. 

The grafting of aromatic groups onto the skeletons of aliphatic ligands such as cyclam and/or the addition of other substituents to the ring is generally reflected by loss of ligand flexibility. For example, the restricted... 

In contrast to the peak selectivity just discussed, there is evidence that the larger, more flexible, ligands tend to exhibit plateau selectivity - a reflection that a number of the larger metal ions are accommodated by the cryptand without major variation in binding energy. 

The need for multiple desolvation of the metal ion in some systems may provide a barrier to complex formation which is reflected by lower formation rates - especially for inflexible macrocycles such as the porphyrins. Because of the high energies involved, multiple desolvation will be unlikely to occur before metal-ion insertion occurs rather, for flexible ligands, solvent loss will follow a stepwise pattern reflecting the successive binding of the donor atoms. However, because of the additional constraints in cyclic systems (relative to open-chain ones), there may be no alternative to simultaneous (multiple) desolvation during the coordination process. 

Combination of the electronically flexible ligands and transition metals... 

Examples of non-symmetric and electronically flexible ligands are shown in Fig. 7, including neutral monoanionic as well as dianionic ligands. The ligands possess HOMO/LUMO energy gap values of <8.5 eV for neutral ligands and <7.0 eV for anionic ligands, at the MNDO-PM3 level calculations. 

A large number of transition metal complexes whose cationic complexes are 10- to 16-electron species (including those with the ligands summarized in Fig. 7) were investigated to determine their potential as ethylene polymerization catalysts with methyaluminoxane (MAO) activation at 25 °C under atmospheric pressure. As a result, we discovered a number of high-activity catalysts for ethylene polymerization that contain electronically flexible ligands [11]. 

Docking flexible ligands to macromolecular receptors by molecular shape, J. Med. 

Three methods can be followed for the synthesis of a SIB catalyst (i) zeolite synthesis around the metal complex (ii) template synthesis and (iii) the flexible ligand method. 

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