標題: Physicochemical characterization of the dimeric lanthanide complexes [en{Ln(DO3A)(H2O)}(2)] and [pi{Ln(DTTA)(H2O)}(2)](2-): a variable-temperature O-17 NMR study
作者: Lee, TM
Cheng, TH
Ou, MH
Chang, CA
Liu, GC
Wang, YM
生物科技學系
Department of Biological Science and Technology
關鍵字: NMR;EPR;H-1 NMR;H-2 NMR;O-17 NMR;Gd(III) complexes;paramagnetic complexes;proton relaxation
公開日期: 1-Mar-2004
摘要: The Gd(III) complexes of the two dimeric ligands [en(DO3A)(2)] {N,N'-bis[1,4,7-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecan-10-yl-methylcarbonyl]-N,N'-ethylenediamine] and [pi(DTTA)(2)](8-) [bisdiethylenetriaminepentaacetic acid (tratis-1,2-cyclohexanediamine)] were synthesized and characterized. The O-17 NMR chemical shift of H2O induced by [en(Dy(DO3A)}(2)] and [pi{Dy(DTTA)}(2)](2-) at pH 6.80 proved the presence of 2.1 and 2.2 inner-sphere water molecules, respectively. Water proton spin-lattice relaxation rates for [en(Gd(DO3A)(H2O)}(2)] and [pi(Gd(DTTA)(H2O)}(2)](2-) at 37.0 +/- 0.1degreesC and 20 MHz are 3.60 +/- 0.05 and 5.25 +/- 0.05 mm(-1) s(-1) per Gd, respectively. The EPR transverse electronic relaxation rate and O-17 NMR transverse relaxation time for the exchange lifetime of the coordinated H2O molecule and the H-2 NMR longitudinal relaxation rate of the deuterated diamagnetic lanthanum complex for the rotational correlation time were thoroughly investigated, and the results were compared with those reported previously for other lanthanide(III) complexes. The exchange lifetimes for [en(Gd(DO3A)(H2O)}(2)] (769 +/- 10 ns) and [pi[Gd(DTTA)(H2O)}(2)](2-) (910 +/- 10 ns) are significantly higher than those of [Gd(DOTA)(H2O)](-) (243 ns) and [Gd(DTPA)(H2O)](2-) (303 ns) complexes. The rotational correlation times for [en{Gd(DO3A)(H2O)}(2)] (150 +/- 11 ps) and [pi[Gd(DTTA)(H2O)}(2)](2-) (130 +/- 12 ps) are slightly greater than those of [Gd(DOTA)(H2O)](-) (77 ps) and [Gd(DTPA)(H2O)](2-) (58 ps) complexes. The marked increase in relaxivity (r(1)) of [en{Gd(DO3A)(H2O)}(2)] and [pi{Gd(DTTA)(H2O)(2)](2-) result mainly from their longer rotational correlation time and higher molecular weight. Copyright (C) 2004 John Wiley Sons, Ltd.
URI: http://dx.doi.org/10.1002/mrc.1315
http://hdl.handle.net/11536/26979
ISSN: 0749-1581
DOI: 10.1002/mrc.1315
期刊: MAGNETIC RESONANCE IN CHEMISTRY
Volume: 42
Issue: 3
起始頁: 329
結束頁: 336
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