Breaking the Symmetry in Molecular Nanorings.
Breaking the Symmetry in Molecular Nanorings.
复制标题
DOI：
10.1021/acs.jpclett.5b02617
复制
发表时间：
2016-01-21
期刊：
影响因子：
--
通讯作者：
Herz LM
中科院分区：
文献类型：
--
作者：
Gong JQ;Favereau L;Anderson HL;Herz LM
由于其独特的电子性质，从苯到天然捕光配合物的环状分子结构受到了广泛的关注。刚性π-共轭模板卟啉纳米环在这里充当优秀的模型系统，因为它们具有可以容易地控制的明确定义的结构，并且因为它们支持高度离域激发。在这项研究中，我们有意识地修改了一系列的六卟啉纳米环，以研究降低旋转对称性对其物理性质的影响。我们发现，作为对称性扭曲的严重性增加沿着的一系列结构，光谱变化和辐射发射强度的增强发生，这来自于转移到最低（k = 0）状态的振子强度。我们发现，偶极允许的第一激发态（k = ±1）的简并度被提升，从而导致了强碎裂纳米环发射的超快偏振开关效应.
Because of their unique electronic properties, cyclic molecular structures ranging from benzene to natural light-harvesting complexes have received much attention. Rigid π-conjugated templated porphyrin nanorings serve as excellent model systems here because they possess well-defined structures that can readily be controlled and because they support highly delocalized excitations. In this study, we have deliberately modified a series of six-porphyrin nanorings to examine the impact of lowering the rotational symmetry on their photophysical properties. We reveal that as symmetry distortions increase in severity along the series of structures, spectral changes and an enhancement of radiative emission strength occur, which derive from a transfer of oscillator strength into the lowest (k = 0) state. We find that concomitantly, the degeneracy of the dipole-allowed first excited (k = ±1) state is lifted, leading to an ultrafast polarization switching effect in the emission from strongly symmetry-broken nanorings.