POTENTIOMETRY AND NMR-STUDIES OF 1,5,9-TRIAZACYCLODODECANE-N,N',N''-TRIACETIC ACID AND ITS METAL-ION COMPLEXES

被引：36

作者：

CORTES, S ^{[1
]}

BRUCHER, E ^{[1
]}

GERALDES, CFGC ^{[1
]}

SHERRY, AD ^{[1
]}

机构：

[1] UNIV TEXAS,POB 830688,RICHARDSON,TX 75083

来源：

INORGANIC CHEMISTRY | 1990年 / 29卷 / 01期

关键词：

D O I：

10.1021/ic00326a003

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

A new chelating macrocycle, 1,5,9-triazacyclododecane-N,N′,N″-triacetic acid (DOTRA), has been synthesized, and its complexes with Zn2+, Cd2+, Ca2+, Mg2+, and Mn2+ have been examined by potentiometry and NMR spectroscopy. The first protonation constant of the free ligand (log K1 = 12.8) was determined spectrophotometrically, while the remaining were evaluated from potentiometric data (log K2 = 7.55, log K3 = 3.65, log K4 = 2.1). DOTRA forms complexes with Mn2+, Mg2+, and Ca2+ rather slowly but reacts much more rapidly with Zn2+ and Cd2+. As reported previously for the nine-membered-ring triaza analogue NOTA, DOTRA also forms a more stable complex with Mg2+ than with Ca2+ (log Kst = 7.1 versus 6.0). High-resolution NMR spectra of the Zn2+, Cd2+, and Mg2+ complexes (log Kst = 19.0, 15.7, and 7.1, respectively) indicate the three six-membered chelate rings are symmetrical and quite rigid in aqueous solution, as evidenced by nonequivalence of all six chelate ring protons. © 1990, American Chemical Society. All rights reserved.

引用

页码：5 / 9

页数：5

共 23 条

[21]

VANDERMERWE MJ, 1983, INORG CHEM, V22, P3489

[22] 1,4,7-TRIAZACYCLONONANE-N,N',N''-TRIACETATE (TCTA), A HEXADENTATE LIGAND FOR DIVALENT AND TRIVALENT METAL-IONS - CRYSTAL-STRUCTURES OF [CRIII(TCTA)], [FEIII(TCTA)], AND NA[CUII(TCTA)].2NABR.8H2O [J].