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

短寿命的手性物种在许多化学领域都很有兴趣，例如在分子马达的设计或光化学引发的不对称有机催化中。捕捉中间体的手性结构是非常困难的，因为这些都是本质上很小的影响(电子CD~10-2，振动CD 10-4-10-5的母体吸收强度)，因此可以检测到光学活性或圆二色(CD)。因此，这些物种的瞬变性质不允许用现有的手性光谱来获得它们的手性结构。在这个项目中，我们希望进一步探索记录在低温基质中分离或产生的手性物种的VCD特征的可能性。推进基质隔离(MI-)VCD光谱，我们将实现对氢作为一种新的软基质主体气体，并证明PH2-MI-VCD将使我们能够稳定并从而研究各种光化学生成的手性物种。特别是，我们想要研究MI-VCD光谱中基质效应的来源，研究手性分子的光化学开环反应以及手性自由基的结构和光谱。我们预计，MI-VCD光谱的发展和应用在文献中都是前所未有的，这将在手性光化学的许多领域引起人们的极大关注，并引发新的理论发展。

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.