Division of Advanced Electronics and Optical Science, Department of Systems Innovation, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
Center for Quantum Information and Quantum Biology, Osaka University, 1-2 Machikaneyama, Toyonaka, Osaka 560-8531, Japan.
J Phys Chem B. 2022 May 19;126(19):3530-3538. doi: 10.1021/acs.jpcb.1c10799. Epub 2022 May 10.
Dissolution dynamic nuclear polarization has been applied in various fields, including chemistry, biology, and medical science. To expand the scope of these applications, the nuclear singlet state, which is decoherence-free against dipolar relaxation between spin pairs, has been studied experimentally, theoretically, and numerically. The singlet state composed of proton spins is used in several applications, such as enhanced polarization preservation, molecular tagging to probe slow dynamic processes, and detection of ligand-protein complexes. In this study, we predict the lifetimes of the nuclear spin states composed of proton spin pairs using the molecular dynamics method and quantum chemistry simulations. We consider intramolecular dipolar, intermolecular dipolar between solvent and solute, chemical shift anisotropy, and spin-rotation interactions. In particular, the relaxation rate of intermolecular dipolar interactions is calculated using the molecular dynamics method for various solvents. The calculated values and the experimental values are of the same order of magnitude. Our program would provide insight into the molecular design of several NMR applications and would be helpful in predicting the nuclear spin relaxation time of synthetic molecules in advance.
溶解动态核极化已应用于化学、生物和医学科学等各个领域。为了扩大这些应用的范围，人们已经在实验、理论和数值上研究了核单态，该单态对自旋对之间的偶极弛豫是无退相干的。由质子自旋组成的单态用于几种应用，例如增强极化保持、分子标记以探测缓慢动态过程和检测配体-蛋白质复合物。在这项研究中，我们使用分子动力学方法和量子化学模拟预测质子自旋对组成的核自旋态的寿命。我们考虑了分子内偶极、溶剂和溶质之间的分子间偶极、化学位移各向异性和自旋-旋转相互作用。特别是，我们使用分子动力学方法计算了各种溶剂中分子间偶极相互作用的弛豫率。计算值和实验值在同一数量级。我们的程序将为几种 NMR 应用的分子设计提供深入了解，并有助于提前预测合成分子的核自旋弛豫时间。
