Modulation of the lifetime of water bound to lanthanide metal ions in complexes with ligands derived from 1,4,7,10-tetraazacyclododecane tetraacetate (DOTA)
Modulation of the lifetime of water bound to lanthanide metal ions in complexes with ligands derived from 1,4,7,10-tetraazacyclododecane tetraacetate (DOTA)
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DOI：
10.1002/hlca.200590086
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发表时间：
2005-01-01
影响因子：
1.8
通讯作者：
Sherry, AD
中科院分区：
文献类型：
--
作者：
Zhang, SR;Jiang, XY;Sherry, AD
合成了一系列DOTA的二酰胺和四酰胺衍生物，并通过多核H-1-、C-13-和O-17-NMR光谱检查了它们的镧系元素（III）配合物，并与类似的已知配合物的文献数据进行了比较（表）。所有配体形成类似于母体[Ln（III）（DOTA）]配合物的结构，其中四个N原子和四个O原子来自DOTA，一个O原子来自内层水分子。有趣的是，内球金属结合水分子的寿命τ（m）变化很大，范围从纳米到毫秒，这取决于侧链酰胺侧链的身份。通常，带正电荷的[Ln（III）（DOTA-四酰胺）]（3+）络合物显示最长的停留时间（高tau（M）值），而在扩展酰胺上具有额外带电官能团的络合物显示小得多的tau（M）值，即使侧基不直接配位到中心Ln（3+）离子。设计具有宽的、可调的tau（M）值范围的新型[Ln（III）（DOTA-四酰胺）]（3+）络合物对于用于研究生理和代谢过程的快速响应、顺磁性化学交换饱和转移（PARACEST）成像剂的应用是至关重要的。
A series of di- and tetraamide derivatives of DOTA were synthesized, and their lanthanide(III) complexes were examined by multinuclear H-1-, C-13-, and O-17-NMR spectroscopy, and compared with literature data of similar, known complexes (Table). All ligands formed structures similar to the parent [Ln(III)(DOTA)]complexes, with four N-atoms and four O-atoms from DOTA and one O-atom from the inner-sphere water molecules. Interestingly, the lifetimes tau(m) of the inner-sphere, metal-bound water molecules vary widely, ranging from nano- to milliseconds, depending on the identity of the pendent amide side chains. In general, positively charged [Ln(III)(DOTA-tetraamide)](3+) complexes display the longest residence times (high tau(M) values), while complexes with additional charged functional groups on the extended amides display much smaller tau(M) values, even when the side groups are not directly coordinated to the central Ln(3+) ions. The design of novel [Ln(III)(DOTA-tetraamide)](3+) complexes with a wide, tunable range of tau(M) values is of prime importance for the application of fast-responding, paramagnetic chemical-exchange-saturation-transfer (PARACEST) imaging agents used for the study of physiological and metabolic processes.