56871-11-5Relevant academic research and scientific papers
Studies of Some Ternary Complexes of Copper(II) involving ?-Bonding Ligands. Part 2
Gopalakrishnan, K.,Bhattacharya, Pabitra K.
, p. 353 - 358 (2007/10/02)
The proton-ligand formation constants of HL, formation constants of the binary complexes + and , and formation constants of the ternary complexes +, where A = 2,2'-bipyridyl, 1,10-phenanthroline, 2-(2'-pyridyl)benzimidazole, or 2-(2'-pyridyl)imidazole, and L = salicylamide ion, salicylanilide ion, 5-bromosalicylamide ion, or 5-bromosalicylanilide ion have been determined in dioxan-water (1 : 1, v/v) solutions, and 0.2 moldm-3 Na, at 30 deg C.The mixed-ligand stability constants KCuAL', for the reaction 2+ + L- +, have been calculated by three methods, namely, graphical linear plot, computer calculations considering complete formation of 2+ prior to the formation of +, and also considering all possible species to be present in solution.The values so obtained are very similar and the concentration plot confirms that the major species present in the solution are only 2+ and +.The value of Δ log K = log KCuAL' - logCuL is positive, except when A is 2-(2'-pyridyl)imidazoline.The majority of the mixed-ligand complexes have been synthesized and characterized.Electronic spectra confirm that there is no significant interaction between the two ligands through the metal d? orbitals in the mixed-ligand complexes.The greater stability of the ternary complexes may be due to a lowering of repulsion between metal d? electrons and the ligand electrons in these compounds.
