配合物的稳定性与配位体酸碱强度之间的直线自由能关系 Ⅹ.铜(Ⅱ)-乙酰甘氨酸-α-氨基酸三元配合物竞争体系

Linear Free Energy Relationships between Stability of Complex Compounds and Strengths of Acid and Base of Ligands Ⅹ.The Copper(Ⅱ)—N-acetylglycine—α-aminoaeid Competitive Ternary Systems

前文[1,4]曾报道金属与第一配位体——2,2′-联吡啶或邻菲啰啉生成稳定配离子再与第二配位体配位的非竞争型的三元配合物的直线自由能关系.

The formation constants of the competitive ternary mixed ligand complexcompounds copper(Ⅱ)-N-acetylglycine—α-aminoacids have been determined by pHmethod at 25℃in the presence of 0.1tool.din-3 NaClO4.Theα-aminoacides used areL-proline,D,L,-α-aminoisobutyric acid,L-isoleucine,L-valine,glycine,L-serine,L-threonine.It was found that linear free energy relationships exist between thestability of the ternary mixed ligand complex compounds and the base strengths of theα-aminoacids and with the stability of the parent binary complex compounds as well.The relevant correlation expressions are as follows:logβ111=6.79+0.391pK2,γ=0.980;logβ111=0.931+1.176logβ101,γ=0.999;logβ111=2.06+0.565 logβ102,β=0.997,whereβ111is the overall stability constant of the ternary complex compounds,β101andβ102arethe overall stability constants of the parent binary complex compounds,pK2 is thedissociation constant of the aminoacid.