Chiral Photochemistry in para-Hydrogen Matrices investigated by Matrix-Isolation VCD Spectroscopy

点击翻译按钮获取中文摘要

Short-lived chiral species are of interest in many fields of chemistry such as in the design of molecular motors or photochemically initiated asymmetric organocatalysis. Capturing the chiral structure of an intermediate, detectable as optical activity or circular dichroism (CD), is very difficult as these are intrinsically small effects (electronic CD ~10-2, vibrational CD 10-4-10-5 of the parent absorbance intensity). Therefore, the transient nature of these species does not allow spectroscopic access to their chiral structure by current chiroptical spectroscopies.In this project, we want to further exploit the possibilities of recording VCD signatures of chiral species isolated or generated in cryogenic matrices. Advancing matrix-isolation (MI-) VCD spectroscopy, we will implement para-hydrogen as a new soft matrix host gas and demonstrate that pH2-MI-VCD will enable us to stabilize and thus study a variety of photochemically generated chiral species. In particular we want to investigate the origin of matrix effects in MI-VCD spectra, study photochemical ring-opening reactions of chiral molecules and the structures and spectra of chiral radicals. We anticipate that the proposed developments and applications of MI-VCD spectroscopy, which are all unprecedented in literature, will attract a lot of attention in many fields of chiral photochemistry, and also trigger new theoretical developments.