Mineo Placido, Villari Valentina, Scamporrino Emilio, Micali Norberto
Dipartimento di Scienze Chimiche and I.N.S.T.M. UdR of Catania, Università di Catania , Viale Andrea Doria 6, I-95125 Catania, Italy.
CNR-IPCF Istituto per i Processi Chimico-Fisici , Viale F. Stagno d'Alcontres 37, I-98158 Messina, Italy.
J Phys Chem B. 2015 Sep 17;119(37):12345-53. doi: 10.1021/acs.jpcb.5b07199. Epub 2015 Sep 3.
In the present study, we show how, in a stagnant water solution of uncharged aggregated achiral porphyrin-based molecules, a mirror-symmetry breaking (SB) can be induced and controlled by means of a weak asymmetric thermal gradient. In particular, it is shown that the optical activity of the aggregate porphyrin solution can be generated and reversed, in sign, only acting on the thermal ramp direction (heating or cooling). In order to avoid data misinterpretation, the aggregate structure modifications with the temperature change and the linear dichroism contribution to circular dichroism spectra were evaluated. A model simulation, using a finite element analysis approach describing the thermal flows, shows that small thermal gradients are able to give rise to asymmetric heat flow. The results reported here can be considered new evidence about the spontaneous symmetry breaking phenomenon induced by very weak forces having an important role in the natural chiral selective processes.
在本研究中，我们展示了在不带电荷的聚集非手性卟啉基分子的静止水溶液中，如何通过弱不对称热梯度诱导和控制镜像对称性破缺（SB）。特别地，研究表明，仅通过作用于热梯度方向（加热或冷却），聚集卟啉溶液的光学活性就可以产生并在符号上反转。为了避免数据误解，评估了温度变化引起的聚集结构变化以及线性二色性对圆二色性光谱的贡献。使用描述热流的有限元分析方法进行的模型模拟表明，小的热梯度能够产生不对称热流。此处报道的结果可被视为关于由非常微弱的力诱导的自发对称性破缺现象的新证据，这种现象在自然手性选择过程中起着重要作用。
