铜与缓冲剂Bicine及芳香氮碱三元混配配合物的稳定性研究

Studies on Stability of Ternary Mixed-Ligand Complexes of Cu(Ⅱ)-Buffer (Bicine)-Heteroaromatic N Bases

用pH电位滴定法测定了HL的酸常数（L＝苯并咪唑，吡啶，3，4－二甲基吡啶，异喹啉）以及二元配合物CuL2＋和三元混配配合物Cu（Bic）L＋（Bic-＝Bicine的单电荷阴离子）的稳定常数．三元混配配合物相对于二元配合物的稳定性用△lgKCu＝lgKCu(Bic)Cu(Bic)L-lgKCuCuL来表示．结果表明由于δ-π协同效应和疏水作用。

The acidity constant of HL (L = Pyridine, 3, 4-Lutidine, Benzimidazole,Iso-quinoline ) and the stability constants of the binary complexes CuL2+ were determined by potentiometric pH titration in aqueous soution (Ⅰ= 0. 1 mol/L NaNO3, 25℃ ). The stabili-ty of the ternary complexes containing in addition N, N-bis (2- hydroxyethyl) glycinate (Bic- ) was firstly measured. The stability of ternary complexes in relation to the stability of their binary parent complexes was characterized by △lg KCu = lgKCu(Bic)Cu(Bic)L - 1gKCuCuL. The re-sults show that these ternary complexes are more stable than would be expected on statistcal grounds because of σ-π cooperative effect and the hydrophobic interaction.