Solvation chemical shifts of perylenic antenna molecules from molecular dynamics simulations.
Solvation chemical shifts of perylenic antenna molecules from molecular dynamics simulations.
复制标题
分子动力学模拟中苝天线分子的溶剂化化学位移。
DOI：
10.1039/c4cp02894e
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
J. Vaara
中科院分区：
文献类型：
--
作者：
N. Özcan;J. Mares;D. Sundholm;J. Vaara
溶剂化诱导的分子性质的变化可以通过采用明确的溶剂分子的动态模型来逼真地模拟。在这项工作中，（13）C NMR化学位移的各种候选天线分子的染料敏化太阳能电池已被研究，通过使用密度泛函理论计算在真空中，并通过采用动态溶剂化模型。溶剂效应进行了研究，使用瞬时分子动力学快照包含天线分子和周围的乙腈溶剂分子。这样的计算考虑到溶剂化引起的化学位移的主要机制。我们分析了溶剂位移的贡献，由于溶剂的磁化率各向异性，虚拟轨道空间的密度变化和可及性的激发态的发音本地磁超精细运营商。我们提出了洛伦兹加宽的化学位移棒光谱中的真空和动态溶剂化模型的结果进行了比较，以图形方式说明。结果表明，溶剂分子的虚态对溶质周边的溶剂可及原子有影响，而溶剂分子的虚态对周边核的超精细算符是可见的.这使得溶质的基态与磁允许激发态的有效耦合成为可能，从而导致周边核的正化学位移贡献。作为溶剂化的结果，周边核的化学位移信号被发现向更大的化学位移值，而溶质分子的内部区域的核显示出相反的趋势。溶剂的磁化率各向异性被发现造成一个小的和几乎恒定的贡献。
Solvation-induced shifts in molecular properties can be realistically simulated by employing a dynamic model with explicit solvent molecules. In this work, (13)C NMR chemical shifts of various candidate antenna molecules for dye-sensitised solar cells have been studied by using density-functional theory calculations both in vacuo and by employing a dynamic solvation model. The solvent effects were investigated using instantaneous molecular dynamics snapshots containing the antenna molecule and surrounding acetonitrile solvent molecules. Such calculations take into account the main mechanisms of solvation-induced chemical shifts. We have analysed the contributions to the solvent shift due to the solvent susceptibility anisotropy, changes in the density of the virtual orbital space and the accessibility of the excited states to the pronouncedly local magnetic hyperfine operator. We present Lorentzian-broadened chemical shift stick spectra in which a comparison of the in vacuo and dynamic-solvation model results is graphically illustrated. The results show that the solvent-accessible atoms at the perimeter of the solute are influenced by the virtual states of the solvent molecules, which are visible to the hyperfine operators of the perimeter nuclei. This enables efficient coupling of the ground state of the solute to the magnetically allowed excited states, resulting in a positive chemical shift contribution of the perimeter nuclei. As a result of solvation, the chemical shift signals of perimeter nuclei are found to be displaced towards larger chemical shift values, whereas the nuclei of the inner region of the solute molecules show the opposite trend. The solvent susceptibility anisotropy is found to cause a small and practically constant contribution.
影响因子：
2.9
作者：
Wang, Junmei;Wang, Wei;Case, David A.
通讯作者：
Case, David A.