钴(Ⅱ)氨基酸配合物分子内配体间疏水作用  

Intramolecular ligand-ligand hydrophobic interactions of complexes of Co(Ⅱ)ion with amino acids

作　　者：乐学义[1] 李维嘉[1] 

机构地区：[1]华南农业大学应用化学系,广东广州510642

出　　处：《化学试剂》2004年第5期259-260,284,共3页Chemical Reagents

基　　金：广东省自然科学基金 ( 0 10 3 3 8) ;广东省教育厅自然科学研究基金 ( 2 0 0 0 70 )

摘　　要：应用pH电位滴定法研究了二元配合物Co(Aa) 2 [Aa-=苯丙氨酸根 (L phe) ,缬氨酸根 (L val) ,亮氨酸根 (L leu) ,异亮氨酸根 (L ile) ,色氨酸根 (L trp) ]在水溶液中的稳定性 [T =2 5℃ ,c=0 1mol/LNaClO4]。配合物Co(Aa) 2 相对于母体配合物Co(Aa) + 稳定性用ΔlogK[ΔlogK =logKCo(Aa)Co(Aa) 2 logKCoCo(Aa) ]表示。结果表明 :与L 丙氨酸 (L ala)配合物Co(L ala) 2 相比 ,所有这些氨基酸配合物Co(Aa) 2 均具有相对较大的ΔlogK ,表明这些配合物分子内存在着额外的稳定化作用。这种稳定性化作用可能主要归因于配合物分子内氨基酸侧链之间的疏水作用 。Stability constants of complexes Co(Aa)_2 have been determined by pH potentiometric titrations in water,where (Aa^-=)L-valinate,L-leucinate,L-isoleucinate,L-tryptophanate and L-phenylalaninate(T=25℃,I=0.1mol/L NaClO_4).The stability of complexes Co(Aa)_2 relative to their parent complexes (Co(Aa)^+) was defined by ΔlogK[ΔlogK=logK^(Co(Aa))_Co(Aa)_2-logK^(Co)_(Co(Aa))].The results showed that,compared with the complex Co(L-ala)_2 with L-alaninate,the complexes with the amino acids had larger ΔlogK values,indicating that there were extra stabilizing effects in the complexes.This might be mainly attributed to the intramolecular hydrophobic interaction between the side chains of two amino acids in the complexes,and the interaction varies with the side chains of the amino acids.

关 键 词：钴配合物 氨基酸 疏水作用 PH电位滴定法 稳定常数 

分 类 号：O614.812[理学—无机化学] O641.4[理学—化学]