Application of laser-interfaced mass spectrometry to biological and pharmaceutical molecules

This thesis demonstrates the use of laser photodissociation spectroscopy to explore the photochemistry of molecular and cluster ions isolated in a commercially adapted mass spectrometer.

Chapter 3 describes gas-phase photodissociation experiments on adenosine nucleotides with phosphate chains of varying lengths with single and double negative charges. Direct comparison between the photochemistry of this series of compounds shows that the adenine π → π* transition is relatively unaffected by the charge state. In addition, the experiments show that photostability is enhanced as the number of phosphate groups increases.

Near-threshold excitation of I-·A and H2PO3-·A is investigated in Chapter 4 to explore whether it leads to electron transfer from the anion to the adenine. It is shown that the adenine dipole-bound excited state is prepared from excitation of I-·A. In contrast, electron detachment in H2PO3-·A occurs from the neutral nucleobase and not from the anion. We identify H2PO3-·A as an example of an anion-molecule cluster where photodetachment initiates intra-molecular hydrogen atom transfer.

Chapters 5 and 6 describe the application of photodissociation spectroscopy to organometallic complexes for CO-releasing applications.