Synthesis and complexation properties of DTPA-N,N″-bis[bis(n-butyl)]-N′-methyl-tris(amide). Kinetic stability and water exchange of its Gd<sup>3+</sup>complex
作者:Z. Jászberényi、É. Tóth、T. Kálai、R. Király、L. Burai、E. Brücher、A. E. Merbach、K. Hideg
DOI:10.1039/b417272h
日期:——
novel DTPA-tris(amide) derivative ligand, DTPA-N,N''-bis[bis(n-butyl)]-N'-methyl-tris(amide)(H2L3) was synthesized. With Gd3+, it forms a positively charged [Gd(L3)]+ complex, whereas with Cu2+ and Zn2+ [ML3], [MHL3]+ and [M2L3]2+ species are formed. The protonation constants of H2L3 and the stability constants of the complexes were determined by pH potentiometry. The stability constants are lower than
合成了新型的DTPA-三(酰胺)衍生物配体DTPA-N,N''-双[双(正丁基)]-N'-甲基-三(酰胺)(H2L3)。使用Gd3 +,它会形成带正电的[Gd(L3)] +复合物,而使用Cu2 +和Zn2 + [ML3],则会形成[MHL3] +和[M2L3] 2+物种。H 2 L 3的质子化常数和配合物的稳定性常数通过pH电位法测定。由于(L3)2- 。[Gd(L3)] +的动力学稳定性通过与Eu3 +,Cu2 +和Zn2 +的金属交换反应速率来表征。通过[Gd(L3)] +的质子和金属离子辅助解离发生的交换反应比[Gd(DTPA)] 2-的反应明显慢,因为酰胺基团不能被质子化并且只能与侵蚀性金属离子发生微弱的相互作用。[Gd(L2)]和[Gd(L3)] +的弛豫度在10-20摄氏度之间恒定,表明水交换相对缓慢。与其他Gd3 + DTPA-双(酰胺)络合物类似,在25摄氏度以上时,弛豫度降低。[Gd(L3)]