通过在真空中和水溶液中进行ab initio的研究,对兰他化物(III) -DOTA复合物的形状特征
Ugo Cosentino1, Alessandra Villa, Demetrio Pitea
1Dipartimento di Scienze dell'Ambiente e del Territorio (DISAT), Università degli Studi di Milano-Bicocca, Piazza della Scienza 1, 20126 Milano, Italy. ugo.cosentino@unimib.it
Journal of the American Chemical Society
|April 25, 2002
概括
计算研究揭示了像加多-DOTA这样的兰坦化物复合物如何改变形状,影响了它们在医学成像中的使用. 计算可以准确预测结构和特性,有助于开发更好的MRI对比剂.
科学领域:
- 计算化学计算化学
- 无机化学 无机化学
- 材料科学 材料科学 材料科学
背景情况:
- 兰化物复合物,特别是那些含有DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) 的复合物,在医学磁共振成像 (MRI) 中作为对比剂至关重要.
- 了解它们的结构性行为和协调几何是优化它们的有效性和安全性的关键.
- 最初的计算提供了一个强大的工具,可以在分子层面上研究这些特性.
研究的目的:
- 使用计算方法来描述四个兰坦化物-DOTA系统 ([Ln ((DOTA) ((H (((2) O) ]) 的构造性行为,其中Ln = La,Gd,Ho,Lu).
- 将计算的几何形状,能量和NMR光谱与实验数据进行比较以验证.
- 阐明不同协调几何体之间的相互转换的机制和能量.
主要方法:
- 最初的计算,包括几何优化和能量计算,在真空和水溶液中使用可极化连续模型 (PCM) 进行.
- 密度函数理论 (DFT) 和Hartree-Fock (HF) 方法被用于有效的核心潜力 (ECP) 兰坦化物.
- 测距独立原子轨道 (GIAO) 和连续集测距转换 (CSGT) 方法用于NMR屏蔽常数计算.
主要成果:
- 两个不同的协调几何学,正方形反 prismatic (A) 和倒置反 prismatic (IA),被确定为[Ln(DOTA) 系统.
- 协调数量有所变化,Lu复合物的IA同位素在溶液中被八度协调,与实验结果保持一致.
- 对Lu-DOTA复杂异构化障碍和 (13) C NMR化学转移的计算预测与实验值密切匹配,验证了计算方法.
结论:
- 这项研究成功地证明了初始计算的能力,可以准确预测兰化物-DOTA复合物的结构和物理化学特性.
- 这些发现提供了对这些复合物的构造偏好的见解,这些复合物跨越了兰他尼德系列,并在不同的环境中 (真空与溶液).
- 这种计算方法有助于兰坦化复合物的表征,支持先进的MRI对比剂的开发.
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