TY - JOUR
T1 - Water-exchange rate and rotational dynamics of [Gd(TTDA-PY)(H 2O)]- and [Gd((S)-4-Bz-TTDA)(H2O)]2- in aqueous solution
T2 - A variable temperature 17O NMR study
AU - Ou, Ming Hung
AU - Liu, Gin Chung
AU - Wang, Yun-Ming
PY - 2004
Y1 - 2004
N2 - 17O NMR longitudinal and transverse relaxation rates and chemical shifts were measured at variable temperatures at 9.4 T magnetic fields for aqueous solutions of two Gd(III) TTDA-like complexes (TTDA = 3,6,10-tri(carboxymethyl)-3,6,10-triazadodecanedioic acid), [Gd(TTDA-PY)(H 2O)]- (TTDA-PY = 3,10-di(carboxymethyl)-6-pyridylmethyl-3, 6,10-triazadodecanedioic acid) and [Gd((S)-4-Bz-TTDA)(H2O)] 2- ((S)-4-Bz-TTDA = ((SH-4-benzyl-3,6,10-tri(carboxymethyl)-3,6,10- triazadodecanedioic acid). The results were analyzed in terms of the water-exchange kinetics and the rotational motion of the complex. The water-exchange kinetic (kex298) parameters for [Gd(TTDA-PY)(H2O)]2- ((30.3 ± 1.8) × 10 6 s-1) and [Gd((S)-4-Bz-TTDA)(H2O)] 2- ((115 ± 2.5) × 106 s-1) are lower than that of [Gd(TTDA)(H2O)]2- (kex 298 = (330 ± 4.0) × 106 s-1) and are significantly higher than that of [Gd(DTPA)(H2O)]2- (kex298 = (4.1 ± 0.3) × 106 s -1)(DTPA = diethylenetriamine-N,N,N′-pentaacetic acid). The higher kex298 values for [Gd((S)-4-Bz-TTDA)(H 2O)]2- and [Gd(TTDA)(H2O)]2- suggest that the longer backbone of the multidentate ligand may be pulled tightly into the first coordination sphere, resulting in high steric constraints at the water binding site. The rotational correlation time (τR) for [Gd(TTDA-PY)(H2O)]- (129 ps) and [Gd((S)-4-Bz-TTDA)(H 2O)]2- (141 ps) are significantly higher than those of [Gd(DTPA)(H2O)]2- (103 ps) and [Gd(TTDA)(H 2O)]2- (75 ps), and this is owing to that τR is related to the magnitude of their molecular weight.
AB - 17O NMR longitudinal and transverse relaxation rates and chemical shifts were measured at variable temperatures at 9.4 T magnetic fields for aqueous solutions of two Gd(III) TTDA-like complexes (TTDA = 3,6,10-tri(carboxymethyl)-3,6,10-triazadodecanedioic acid), [Gd(TTDA-PY)(H 2O)]- (TTDA-PY = 3,10-di(carboxymethyl)-6-pyridylmethyl-3, 6,10-triazadodecanedioic acid) and [Gd((S)-4-Bz-TTDA)(H2O)] 2- ((S)-4-Bz-TTDA = ((SH-4-benzyl-3,6,10-tri(carboxymethyl)-3,6,10- triazadodecanedioic acid). The results were analyzed in terms of the water-exchange kinetics and the rotational motion of the complex. The water-exchange kinetic (kex298) parameters for [Gd(TTDA-PY)(H2O)]2- ((30.3 ± 1.8) × 10 6 s-1) and [Gd((S)-4-Bz-TTDA)(H2O)] 2- ((115 ± 2.5) × 106 s-1) are lower than that of [Gd(TTDA)(H2O)]2- (kex 298 = (330 ± 4.0) × 106 s-1) and are significantly higher than that of [Gd(DTPA)(H2O)]2- (kex298 = (4.1 ± 0.3) × 106 s -1)(DTPA = diethylenetriamine-N,N,N′-pentaacetic acid). The higher kex298 values for [Gd((S)-4-Bz-TTDA)(H 2O)]2- and [Gd(TTDA)(H2O)]2- suggest that the longer backbone of the multidentate ligand may be pulled tightly into the first coordination sphere, resulting in high steric constraints at the water binding site. The rotational correlation time (τR) for [Gd(TTDA-PY)(H2O)]- (129 ps) and [Gd((S)-4-Bz-TTDA)(H 2O)]2- (141 ps) are significantly higher than those of [Gd(DTPA)(H2O)]2- (103 ps) and [Gd(TTDA)(H 2O)]2- (75 ps), and this is owing to that τR is related to the magnitude of their molecular weight.
KW - Contrast agent
KW - Gadolinium(III) complexes
KW - MRI
KW - O NMR
KW - Rotational correlation time
KW - Water-exchange rate
UR - http://www.scopus.com/inward/record.url?scp=28244484989&partnerID=8YFLogxK
U2 - 10.1002/jccs.200400170
DO - 10.1002/jccs.200400170
M3 - Article
AN - SCOPUS:28244484989
SN - 0009-4536
VL - 51
SP - 1147
EP - 1152
JO - Journal of the Chinese Chemical Society
JF - Journal of the Chinese Chemical Society
IS - 5 B
ER -