碳碳三键振动探针的非线性红外光谱

Carbon-Carbon Triple Bond as a Vibrational Marker in Ultrafast Nonlinear Infrared Spectroscopy

利用飞秒红外光谱实验和计算化学手段,我们研究了含碳碳三键(C≡C)的多个分子体系的结构与超快动力学。首先是六(三甲基硅-乙炔基)苯(HTEB),我们发现C≡C基团的振动强度得到显著增强,其跃迁偶极矩的强度可与典型的碳氧双键媲美。发现了对称性破缺,导致简并的C≡C振动发生劈裂,并研究了两种非简并的C≡C振动模式之间发生在皮秒时间尺度上的分子内能量再分布过程。进一步,我们将含有C≡C基团的分子引入DNA碱基和肽分子中,作为这些分子体系的外源结构坛子,探测其局部结构动力学。

In this work,femtosecond two-dimensional infrared(2DIR)spectroscopy and computations were used to examine the structure and ultrafast dynamics of C≡C containingmolecularsystems.Firstexampleishexakis[(trimethylsilyl)ethynyl]benzene(HTEB),a significantly intensity-enhanced C≡C stretching infrared(IR)absorption is observed,whose IR transition dipole magnitude becomes comparable to that of a typical C≡C stretch.Molecular symmetry breaking was observed in HTEB,and a picosecond intramolecular energy redistribution process was observed between two non-degenerate C≡C stretching modes.Further,C≡C containing species were introduced into DNA bases and peptides as an extrinsic structural probe,with the aim of examining local structural and dynamics of these biomolecules.