Zur Untersuchung,在世界各地的澳大利亚,自然界的内在力量Liganden das Gleichgewicht zwischen den paramagnetischen,blauen Komplexen(I)和den diamagnetischen,gelben Komplexen(II)beeinflust,wimitmiten没关系。
Anions as stabilizing ligands for Ni(III)(cyclam) in aqueous solutions
作者:Dror Shamir、Israel Zilbermann、Eric Maimon、Alexander I. Shames、Haim Cohen、Dan Meyerstein
DOI:10.1016/j.ica.2010.03.057
日期:2010.10
Abstract Several new anions were shown to be good stabilizing ligands for Ni(III)L(H 2 O ) 2 3 + , (L = 1,4,8,11-tetraazacyclotetradecane, cyclam) in aqueoussolutions. Mo 7 O 24 6 - , phosphonates, phosphates, including the biological relevant ATP were shown to have the highest binding constants to the tervalent nickel ion. The results suggest that the charge density of the anion at the binding site
Bicyclam [6,6′-bi(1,4,8,11-tetra-azacyclotetradecane)]: a ditopic receptor for homo- and hetero-bimetallic complexes
作者:Luigi Fabbrizzi、Laura Montagna、Antonio Poggi、Thomas A. Kaden、Liselotte C. Siegfried
DOI:10.1039/dt9870002631
日期:——
Bicyclam [6,6′-bi(1,4,8,11-tetra-azacyclotetradecane)](L2) was prepared by reducing 6,6′-bi(1,4,8,11-tetra-azacyclotetradecan-5,7-dione)(L1) with B2H6 in bis(2-methoxyethyl) ether. Ligand L2 forms homo- and hetero-binuclear complexes with Cu2+ and Ni2+, the spectral properties and the electrochemistry of which have been studied. Whereas the visible spectra are very similar to those of the mononuclear
A new technique, based on microwaveheating, is proposed for the determination of thermodynamicfunctions of chemicalreactions. The reliability of the method has been varified by studying two typical chemical equilibria (complex-formation and acid–base) as well as the temperature behaviour of several polar solvents. The absence of temperature gradients inside the sample, the broad range of variability
Formation and homolysis of organonickel(III) complexes
作者:Douglas G. Kelley、Adam Marchaj、Andreja Bakac、James H. Espenson
DOI:10.1021/ja00020a020
日期:1991.9
The reactions of Ni(1,4,8,11-tetraazacyclotetradecane)2+ with alkyl radicals were studied. Data were collected for the R,R,S,S (or beta) and R,R,R,R (or alpha) isomers. The reactions form sigma-bonded organometallic cations, as in the equation NiL2+ + R. + H2O reversible RNiL(H2O)2+. The values of the rate constants for the forward (colligation) and reverse (homolysis) reactions were measured separately by laser flash photolysis techniques with a kinetic probe. The values of k(col) lie in the order CH3 >> primary >> secondary, and just the reverse order applies to k(hom). Thus the equilibrium constants for formation of RNiL(H2O)2+, given by k(col)/k(hom), are most favorable for methyl and least favorable for secondary alkyls. These nickel-alkyl bonds are much weaker than those in corresponding cobalt and chromium complexes. For that reason, values of k(col) vary widely with the nature of R.. Values of k(col) are considerably higher for alpha-Ni(cyclam)2+ than for the beta-isomer, and the reverse order applies to k(hom). Also, the alpha-isomer has the highest equilibrium constant for the formation equilibrium. The kinetic and thermodynamic trends can be rationalized by structural effects.