21524-04-9Relevant academic research and scientific papers
Ligand substitution kinetics and equilibria in the systems formed by tetrabromoaurate(III) anion and heterocyclic nitrogen donors
Cattalini, Lucio,Chessa, Gavino,Michelon, Gianni,Pitteri, Bruno,Tobe, Martin L.,Zanardo, Andrea
, p. 3409 - 3413 (2008/10/08)
The kinetics of the forward and reverse reactions [AuBr4]- + am = [AuBr3(am)] + Br- has been studied in 95/5 vol % methanol/water mixtures at 25.0°C for am = pyridine and a variety of substituted pyridines. When there is methyl substitution on both the 2- and 6-positions, the low stability of the amine complexes precludes a study of the kinetics of their formation. However, they can be prepared and the kinetics of their decomposition are reported. The second-order rate constants for the forward and reverse reactions depend upon the amine basicity and take the form log kf2 = a(pKa) + b and log kr2 = -a(pKa) + b′ where a and a′ are independent of the extent of ortho substitution in the ligand. In contrast to the case for the chloro analogues, the reactions in both directions are retarded by 2(6)-methyl substituents in the pyridine ring, manifested by a change in b and b′.
