- 作者: 歐明鴻、劉金昌、王雲銘
- 作者服務機構: Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan, R.O.C.
- 中文摘要: 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)(H2O)]- (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 = ((S)-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)]- ((30.3 ± 1.8)×106 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- (kex298 = (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',N",N"-pentaacetic acid). The higher kex298 values for [Gd((S)-4-Bz-TTDA)(H2O)]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 (tR) for [Gd(TTDA-PY)(H2O)]- (129 ps) and [Gd((S)-4-Bz-TTDA)(H2O)]2- (141 ps) are significantly higher than those of [Gd(DTPA)(H2O)]2- (103 ps) and [Gd(TTDA)(H2O)]2- (75 ps), and this is owing to that tR is related to the magnitude of their molecular weight.
- 英文摘要: --
- 中文關鍵字: 17O NMR; Water-exchange rate; Rotational correlation time; MRI; Contrast agent; Gadolinium(III) complexes.
- 英文關鍵字: --