Time-Resolved Chiral Vibrational Spectroscopy

Advances in infrared laser technology and detection sensitivity have made time-resolved chiral vibrational spectroscopy experimentally feasible. Here we describe our recent efforts in detecting, for the first time, transient vibrational circular dichroism (VCD) signals with picosecond time resolution. The absorption changes of the cobalt (?)-sparteine complex Co(sp)Cl2 after visible excitation of a d-d excited state was probed in the CH-stretch region by alternating left- and right-handed circular polarized mid IR laser pulses. VCD spectra can be sensitive reporters of peptide and protein secondary structure or the absolute configuration of chiral organic compounds in solution. Recent developments are presented, which may in the future allow us to access this information in the course of fast chemical reactions.