Bringing to light transient molecular structure and function using advanced vibrational spectroscopy

As chemical synthetic methods have developed so has the complexity and functionality of synthesised compounds. In order to investigate their structure and function, especially when the function results from a perturbation, more sophisticated spectroscopic techniques have to be employed. This thesis is concerned with utilising advanced vibrational spectroscopic techniques to investigate a multitude of complex compounds ranging from molecular rotors and photochromic compounds to chiral structures such as enantioselective supramolecular catalysts. To probe this wide range of molecular systems two methods are employed, time-resolved vibrational spectroscopy and vibrational circular dichroism, which use infrared radiation to probe the vibrational modes of the compounds.
Time-resolved vibrational spectroscopy has been used to understand: How a change in the symmetry of a previously successful photochromic compound inhibits its ability to cyclise, the complete life cycle of a prototypical photochromic compound by demystifying the current qualitative description, and finally to probe the dynamics of a sensitive BODIPY-based fluorescent molecular rotor. Vibrational circular dichroism, a technique sensitive to chirality, aided in the discovery of the structure of a supramolecular catalyst that yields the highest enantioselectivity. Also an extension onto the work of amplified vibrational circular dichroism is reported using a very large amplifier that can occupy multiple redox state.