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Title: pH dependence of relaxivities and hydration numbers of gadolinium(III) complexes of macrocyclic amino carboxylates

Abstract

In the authors' previous paper, they reported the pH dependence of T[sub 1] relaxivities (R[sub 1], the second-order rate constant that describes the catalytsis of T[sub 1] relaxation by a paramagnetic species) for Gd(III) complexes, and hydration numbers (q, the number of inner-sphere coordinated water molecules) for analogous Tb(III) complexes of the linear amino carboxylic acid ligands: EDTA, HEDTA, EGTA, DTPA, and TTHA. A plot of R[sub 1] vs q values for all the complexes of the linear amino carboxylic acids in monomeric forms gave a straight line with an intercept of 2.2[plus minus]0.1 (mM s)[sup [minus]1] and a slope of 1.6[plus minus]0.1 (mM s)[sup [minus]1] per coordinated water. It was concluded that the intercept represents the outer-sphere relaxivity for these Gd(III) complexes, and the slope represents the estimated contribution of each inner-sphere water to R[sub 1]. To further examine the effect of charge and ligand structure on the relaxation behavior, they have determined the relaxivities and inner-sphere hydration numbers of Gd(III) and Tb(III) complexes of three macrocyclic amino carboxylic acids, i.e., DO3A, HP-DO3A, and DOTA as a function of solution pH. An energy-transfer quenching experiment using Eu(III) and Tb(III) complexes was carried out to detect any marked tendency tomore » form oligomers in these macrocyclic complex solutions. 24 refs., 4 figs., 1 tab.« less

Authors:
; ; ; ; ;  [1]
  1. Bristol-Myers Squibb Pharmaceutical Research Inst., New Brunswick, NJ (United States)
Publication Date:
OSTI Identifier:
7070105
Resource Type:
Journal Article
Journal Name:
Inorganic Chemistry; (United States)
Additional Journal Information:
Journal Volume: 31:26; Journal ID: ISSN 0020-1669
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; GADOLINIUM COMPLEXES; HYDRATION; SPIN-LATTICE RELAXATION; AMINES; CARBOXYLIC ACIDS; EUROPIUM COMPLEXES; LIGANDS; LUMINESCENCE; PH VALUE; TERBIUM COMPLEXES; COMPLEXES; ORGANIC ACIDS; ORGANIC COMPOUNDS; RARE EARTH COMPLEXES; RELAXATION; SOLVATION; 400201* - Chemical & Physicochemical Properties

Citation Formats

Zhang, Xun, Chang, C A, Brittain, H G, Garrison, J M, Telser, J, and Tweedle, M F. pH dependence of relaxivities and hydration numbers of gadolinium(III) complexes of macrocyclic amino carboxylates. United States: N. p., 1992. Web. doi:10.1021/ic00052a040.
Zhang, Xun, Chang, C A, Brittain, H G, Garrison, J M, Telser, J, & Tweedle, M F. pH dependence of relaxivities and hydration numbers of gadolinium(III) complexes of macrocyclic amino carboxylates. United States. https://doi.org/10.1021/ic00052a040
Zhang, Xun, Chang, C A, Brittain, H G, Garrison, J M, Telser, J, and Tweedle, M F. 1992. "pH dependence of relaxivities and hydration numbers of gadolinium(III) complexes of macrocyclic amino carboxylates". United States. https://doi.org/10.1021/ic00052a040.
@article{osti_7070105,
title = {pH dependence of relaxivities and hydration numbers of gadolinium(III) complexes of macrocyclic amino carboxylates},
author = {Zhang, Xun and Chang, C A and Brittain, H G and Garrison, J M and Telser, J and Tweedle, M F},
abstractNote = {In the authors' previous paper, they reported the pH dependence of T[sub 1] relaxivities (R[sub 1], the second-order rate constant that describes the catalytsis of T[sub 1] relaxation by a paramagnetic species) for Gd(III) complexes, and hydration numbers (q, the number of inner-sphere coordinated water molecules) for analogous Tb(III) complexes of the linear amino carboxylic acid ligands: EDTA, HEDTA, EGTA, DTPA, and TTHA. A plot of R[sub 1] vs q values for all the complexes of the linear amino carboxylic acids in monomeric forms gave a straight line with an intercept of 2.2[plus minus]0.1 (mM s)[sup [minus]1] and a slope of 1.6[plus minus]0.1 (mM s)[sup [minus]1] per coordinated water. It was concluded that the intercept represents the outer-sphere relaxivity for these Gd(III) complexes, and the slope represents the estimated contribution of each inner-sphere water to R[sub 1]. To further examine the effect of charge and ligand structure on the relaxation behavior, they have determined the relaxivities and inner-sphere hydration numbers of Gd(III) and Tb(III) complexes of three macrocyclic amino carboxylic acids, i.e., DO3A, HP-DO3A, and DOTA as a function of solution pH. An energy-transfer quenching experiment using Eu(III) and Tb(III) complexes was carried out to detect any marked tendency to form oligomers in these macrocyclic complex solutions. 24 refs., 4 figs., 1 tab.},
doi = {10.1021/ic00052a040},
url = {https://www.osti.gov/biblio/7070105}, journal = {Inorganic Chemistry; (United States)},
issn = {0020-1669},
number = ,
volume = 31:26,
place = {United States},
year = {Wed Dec 23 00:00:00 EST 1992},
month = {Wed Dec 23 00:00:00 EST 1992}
}