二阶非线性光学方法研究界面超分子手性的动态调控

手性是生命物质和自然界的基本特性并以各种尺度存在于自然界。超分子层次的手性问题是连接分子层次与宏观尺度（包括纳米尺度）的手性的关键。超分子手性的研究不仅对于理解与模拟自然界中手性的起源乃至于生命的起源提供了可行的思路，超分子组装方法也是近年来制备手性材料的重要方法。界面超分子手性的调控是手性研究的前沿领域。如何原位在线的研究界面超分子手性的调控机理是一个极具挑战性的问题。二阶非线性光学方法为此提供了机会。本项目用二次谐波-线二色谱（SHG-LD）及和频光谱-线二色谱（SFG-LD）研究各种物理外场（光、温度、磁场、电极电势）和化学环境（PH、离子、浓度）对卟啉体系、偶氮苯体系、联乙炔两亲分子体系界面超分子手性的光谱、结构和手性形成分子机理的影响。探讨总结这些物理外场和化学环境对界面超分子调控的本质和一般规律。本研究将会极大地更新、深化和丰富对界面手性调控机理的深层次的认识。

Chirality is a characteristic of living matter and nature，which exist in various hierarchical levels in nature. Chirality at a supramolecular level is the key to connecting the chirality between the molecular scale and the macroscopic scale (including nanoscopic scale). Studying the supramolecular chirality can n provide the possible clue to understanding and simulating the origin of the homochirality in life and then the origin of life. Also, the supramolecular chirality by a self-assembly can provide an important method to fabricate the chiral material. Regulating supramolecular surface chirality has been a frontier in the chiral studies. How to monitor the supramolecular regulation in situ is a very challenging question, and second nonlinear optical spectroscopy can offer an opportunity to probe the surface supramolecular chirality at the Langmuir films in situ. In this project, we will use Second Harmonic Generation (SHG) and Sum Frequency Generation (SFG) spectroscopy to investigate the effects of external physical fields (light, temperature, magnetic field and electrode potential), on the chiral spectroscopy, chiral structure and chiral formation mechanism of the porphyrin system, azobenzene system and diacetylene amphipathic molecule system. Furthermore, we also study the effect of the chemical factors (pH, ions and concentration) on these systems. From these investigations, we will summarize the general rule of affecting supramolecular chiral regulation, which is anticipated to yield a deep understanding of the regulation mechanism of the supramolecular chirality.