Toward the Prediction of Water Exchange Rates in Magnetic Resonance Imaging Contrast Agents: A Density Functional Theory Study

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• 作者：Mart铆n Regueiro-Figueroa ; Carlos Platas-Iglesias
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：June 18, 2015
• 年：2015
• 卷：119
• 期：24
• 页码：6436-6445
• 全文大小：424K
• ISSN：1520-5215

文摘

We present a theoretical investigation of Gd鈥揙_water bonds in different complexes relevant as contrast agents in magnetic resonance imaging (MRI). The analysis of the Ln鈥揙_water distances, electron density (蟻_BCP), and electron localization function (ELF) at the bond critical points of [Ln(DOTA)(H₂O)]^{鈭?/sup> and [Ln(DTPA-BMA)(H₂O)] indicates that the strength of the Ln鈥揙_water bonds follows the order DTPA-BMA > DOTA (M isomer) > DOTA (m isomer). The ELF values decrease along the 4f period as the Ln鈥揙_water bonds get shorter, in line with the labile capping bond phenomenon. Extension of these calculations to other Gd3+ complexes allowed us to correlate the experimentally observed water exchange rates and the calculated 蟻_BCP and ELF values. The water exchange reaction becomes faster as the Gd鈥揙_water bonds are weakened, which is reflected in longer bond distances and lower values of 蟻_BCP and ELF. DKH2 calculations show that the two coordinated water molecules may also have significantly different 17O hyperfine coupling constants (HFCCs).}