Electron and proton transfer (ET/PT) are two of the most fundamental processes in chemistry. Proton-coupled ET (PCET) refers to reactions involving the exchange and release of both proton and electron species. These reactions play significant roles in biological processes (e.g. respiration, nitrogen fixation, photosynthesis), organic synthesis (e.g. hydrogen atom transfer), and solar fuel and artificial photosynthesis (e.g. catalysis). Our group is interested in tackling the problem of charge transfer processes using a variety of spectroscopic and computational tools. We are also open to collaborations, especially interdisciplinary research, as we value the unique contributions that each scientist or investigator brings to a problem.
Our current project:
Photoacids, molecules which increase in acidity upon electronic excitation, are ideal candidates for controlled PT studies. They have been investigated as possible proton generators and fluorescence pH/chemical probes for biological study. Application of green fluorescent proteins (GFP) for fluorescence imaging and chemical sensing have revolutionized the field of molecular cellular biology. The chromophore of GFP is a photoacid whose remarkable quantum yield is a result of excited state stabilization by the protein matrix. Thus, there is considerable interest in understanding both the PT and photodecay processes of photoacids in a lipid/protein framework.
We focus on examining inter- and intramolecular PT mechanisms of photoacids with multi-proton binding sites in different solvent and increasing complex environments, including reverse micelles and proteins. Fluorescence spectroscopy is an extremely sensitive analytical technique that can probe both excited state dynamics and changes in the environment. We will use a combination of steady-state fluorescence spectroscopy and time-correlated single photon counting to investigate PT.
Kana Takematsu
Associate Professor of Chemistry and Biochemistry, on leave for the 2023–2024 academic year
Kana Takematsu became interested in physical chemistry after working in Laurie Butler’s lab to investigate gas phase dynamics during her undergraduate studies at University of Chicago. She pursued her interests in graduate school at Caltech, working with Mitchio Okumura to study the spectroscopy and kinetics of gas phase intermediates in the Earth’s atmosphere. She then joined Harry Gray’s group at Caltech for her postdoctoral work to extend her training to the condensed phase, studying charge transfer processes in metal-modified azurin mutants and inorganic complexes. In July 2015, she joined the Department of Chemistry at Bowdoin College as an assistant professor in chemistry and biochemistry.
Education
- PhD, California Institute of Technology
- BS, University of Chicago