超快多维红外光谱学:分子结构的时空分辨

Ultrafast Multi-Dimensional Infrared Spectroscopy:Spatial-and Time-Resolved Molecular Structures

利用时间分辨的超快二维红外(2DIR)光谱、稳态一维红外光谱等手段,本文探讨了从溶液中的小分子体系到生物大分子体系的超快振动特性及所反映的分子结构动力学过程。研究了五羰基溴化锰在四氯化碳中的时间分辨2DIR光谱,发现了分子对称性增强的13 CO配体的红外吸收信号,并利用2DIR对角峰和非对角峰表征了其与12 CO配体振动态的相互作用和分子内能量传递过程;实现了钌羰基配合物在光敏黄色蛋白突变体M100A上的定点标记,并研究了该外源标记物的羰基配体的结构动力学,发现了探针分子的振动光谱指纹对其所处的空间位置的敏感性,还发现该探针分子的振动扩散过程对水相中的蛋白质结构涨落具有灵敏性。

In this work,time-resolved two-dimensional infrared(2DIR)and steady-state 1DIR spectroscopic methods were utilized to probe molecular structures and dynamical processes of small molecules and small molecule-labeled bio-molecules in solution phases.Time-depended 2DIR spectra of Mn(CO)5Br in CCl4 were examined,from which molecular-symmetry enhanced13 CO natural abundant isotopic IR absorption signal was identified.Diagonal and associated off-diagonal 2DIR peaks were used to characterize the intramolecular vibrational redistribution dynamics among the CO stretching vibrational states of the 13 CO-and12 CO species.In another study,a Ru-carbonyl complex was successfully bound to photoactive yellow protein(PYP)M100Amutant.The characteristic vibrational signal of the extrinsic label was used to report structural and spatial characteristics of the binding sites.Vibrational spectral diffusion of the Ru-carbonyl stretching was extracted from 2DIR spectra and was found to be very sensitive to the aqueous-phase protein structural fluctuations.