(4,4′)-Bipyridine in vacuo and in solvents: a quantum chemical study of a prototypical floppy molecule from a molecular transport perspective
(4,4′)-Bipyridine in vacuo and in solvents: a quantum chemical study of a prototypical floppy molecule from a molecular transport perspective
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DOI：
10.1039/c2cp43627b
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发表时间：
2013-01-01
影响因子：
3.3
通讯作者：
Wenzel, Wolfgang
中科院分区：
文献类型：
--
作者：
Baldea, Ioan;Koeppel, Horst;Wenzel, Wolfgang
报道了(4，4‘)-联吡啶(44BPY)的中性和阴离子物种的量子化学计算结果，这是一种典型的松软自由度分子，置于真空和溶剂中。除了平衡几何结构和振动频率和光谱外，我们还给出了振动模式的绝热能量曲线，并在电荷转移时进行了显著的分子内重组。特别注意了44bPY的软性强非简谐自由度，这与最显著的结构特征，即两个吡啶环之间的扭角θ有关。将强调本研究结果与分子传输的相关性。我们证明了溶剂起到了选择性栅电极的作用，并提出了一个剪刀算子来解释溶剂对分子传输的影响。我们关于电导G与cos(2)的结果与先前的微观分析所表明的垂直构象中的显著透射率是一致的。
We report results of quantum chemical calculations for the neutral and anionic species of (4,4')-bipyridine (44BPY), a prototypical molecule with a floppy degree of freedom, placed in vacuo and in solvents. In addition to equilibrium geometries and vibrational frequencies and spectra, we present adiabatic energy curves for the vibrational modes with significant intramolecular reorganization upon charge transfer. Special attention is paid to the floppy strongly anharmonic degree of freedom of 44BPY, which is related to the most salient structural feature, namely the twist angle theta between the two pyridine rings. The relevance of the present results for molecular transport will be emphasized. We show that the solvent acts as a selective gate electrode and propose a scissor operator to account for solvent effects on molecular transport. Our result on the conductance G vs. cos(2) theta is consistent with a significant transmission in perpendicular conformation indicated by previous microscopic analysis.