Polarization of ligands

Volkov, Grischenko and Delimarsky [293] mentioned a similar tendency of the complexes to increase in strength with the increase in the polarity of ligands along the sequence F to I. This concept confirms the significance of the covalent share in the energetics of the formation of complex ions in molten media. 

Evaluation of Relative Polarity of Ligands Using the Pauling Electronegativity Scale... 

The appearance of the seventh ligand (Xn ) predominantly in the first coordination sphere of the complex or outside of the complex depends on the polarization potential of the alkali metal cation, M+, and on the polarity of the seventh anion, Xn". Increased polarity of the anion favors its entering into the first coordination sphere of the complex ion. 

Theories based on cr-effects consider that the more electronegative a ligand the more polarization of the metal occurs, weakening the bond trans to it. This can alternatively be viewed in terms of electronic transmission via a <7-type (p) orbital shared by the two ligands. 

Table IV presents the results of the determination of polyethylene radioactivity after the decomposition of the active bonds in one-component catalysts by methanol, labeled in different positions. In the case of TiCU (169) and the catalyst Cr -CjHsU/SiCU (8, 140) in the initial state the insertion of tritium of the alcohol hydroxyl group into the polymer corresponds to the expected polarization of the metal-carbon bond determined by the difference in electronegativity of these elements. The decomposition of active bonds in this case seems to follow the scheme (25) (see Section V). But in the case of the chromium oxide catalyst and the catalyst obtained by hydrogen reduction of the supported chromium ir-allyl complexes (ir-allyl ligands being removed from the active center) (140) C14 of the...

Analysis of Ligand Binding in the Intact Cell. A model of LR dynamics in the intact cell consistent with the results of these studies is presented in Figure 6, and a fit to the data of a polarization binding experiment is shown. The model has these characteristics ... 

Middle panel The data are a continuous polarization analysis of ligand binding (1 nW FLPEP) to lO cells/mL at 37 C, which represents LR.j,, the sum of occupied receptors in all... 

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