臺灣博碩士論文加值系統

本報告首先合成兩個直鏈型DTPA-雙醯胺衍生物,DTPA-BMOBA(
diethylenetriamine-N,N',N"-triacetic-N,N"-bis(N-2-
methoxybenzylamide))與DTPA-BMOPEA(diethylene-triamine-N,N',N"-
triacetic-N,N"-bis(N-2-methoxyphenethylamide))及兩個EDTA-雙醯胺
衍生物,EDTA-BMOBA(ethylenediamine-N,N'-diacetic-N-N'-bis(N-2-
methoxy-benzylamide))與EDTA-BTBA(ethylenediamine-N,N'-diacetic-
N.N'-bis(tert-butyl-amide))等有機配位子.在熱力學性質方面,有機配
位子之質子化常數乃利用電位滴定法(0.10 mol dm-3 KCl)求得,同時亦利
用NMR-pH滴定法確認有機配位子被質子化之位子. 配位子與釓(III),鋅(
II),鈣(II)及銅(II)等金屬離子形成金屬錯合物之穩定常數亦由電位滴定
法獲得.結果顯示,釓金屬錯合物之穩定常數較鋅,鈣及銅等金屬離子所形
成之金屬錯合物之穩定常數高.另外,釓金屬錯合物分別與鋅,鈣及銅等金
屬離子所形成之金屬錯合物之選擇常數及修飾化選擇常數亦被討論之.最
後,在20MHz的磁場條件下,研究不同pH值對金屬錯合物的自旋-晶格弛緩
率(spin-lattice relaxivity,R1)之影響.結果顯示,[Gd(DTPA-BMOBA)]及
[Gd(DTPA-BMOPEA)]的R1值相似於其他DTPA-雙醯胺衍生物之釓金屬錯合
物,其理由是有相同之配位數及內層水分子數目.另外,在酸性的範圍(pH <
3)時,釓金屬錯合物的弛緩率隨著pH值的上升而降低,但是當釓金屬離子和
有機配位子完全形成金屬錯合物時,其R1值便不再改變.

Two linear bis(amide) derivaties of DTPA-(diethylenetriamine-
N,N,N',N",N"- pentaacetic acid),DTPA-BMOBA(diethylenetriamine-N,
N',N"-triacetic-N,N"-bis(N-2-methoxybenzylamide)) and DTPA-
BMOPEA(diethylenetriamine-N,N',N"-triacetic-N,N"-bis(N-2-
methoxyphenethylamide)) and two linear bis(amide) derivaties of
EDTA(ethylenediamine-N,N'-diacetic acid), EDTA-BMOBA(
ethylenediamine-N,N'-diacetic-N,N'-bis(N-2-methoxybenzylamide))
and EDTA-BTBA(ethylenediamine-N,N'-diacetic-N,N'-bis(tert-
butylamide)) were synthesized. Their protonation constants
weredetermined by potentiometric titration with 0.10 mol dm-3
KCl andby NMR pH titration at 25.0+0.1. The stability constants
of the complexes of calcium(II), zinc(II), copper(II) and
gadolinium(III) with DTPA-BMOBA, DTPA-BMOPEA, EDTA-BMOBA and
EDTA-BTBA were also quantitatively investigated bypotentiometic
technique. The stability constants determined for Gd(III)
islarger than those for Ca(II), Zn(II) and Cu(II) with DTPA-
BMOBA and DTPA-BMOPEA. The selectivity constants and modified
selectivity constants for Gd(III) with the ligands over
endogenously available metal ions were calculated and discussed.
Spin-lattice relaxivities(R1, 20MHz) of the complexes of Gd(III)
with DTPA-BMOBA and DTPA-BMOPEA as a function of pH were
determined. The similar rela-xivity R1 of the complexes of [Gd(
DTPA-BMOBA)] and [Gd(DTPA-BMOPEA)] suggestthat they contain
similar inner-sphere water and coordination numbers. Theobserved
relaxivity R1 decreased with the increasing pH in the acid
region below pH 3. Once a Gd(III) complex were fully formed, the
relaxivity became a constant, and the limiting value correlated
well with the number of inner-sphere-coordinated water
molecules.