Reaction mechanisms and reactive interemdiates, especially those relevant to biochemical processes. Photochemistry, photobiology, and environmental photochemistry. Fast and ultrafast laser spectroscopy. Electron transfer reactions and ion radical chemistry. Nitrenium ions and other biologically important electrophiles. Photoenzymatic repair of DNA. Design and synthesis of photochemical triggering agents. Photochemical degradation of drugs and natural products.
Major Recognitions and Honors
Significant Professional Service and Activities
Inter-American Photochemical Society: Treasurer 1994-1999. ). Co-Chair and Organizer for the 14th Winter Meeting, January 2-5 2003. Reaction Mechanisms Conference Board of Directors 2004-present. National Science Foundation: CRIF-MRI Panel, June 1998. National Institutes of Health: Study Section on Microscopic Imaging March 18, 2004. Study Section on Bioengineering Research Partnerships, March 19, 2004. Pixelligent Technologies, LLC. Member, Technical Advisory Board 2003-present.. University of Maryland. University Senate 2005-present, Graduate Council 1998-2001.
One area of research in the Falvey Group is the mechanistic design, synthesis and study of photoreleasable protecting groups. The overall goal is to create a suite of protecting groups whose release can be triggered using inexpensive visible light sources. One specific strategy has been to photoinduced electron transfer from visible-light absorbing dyes to a protecting group that can be activated through photoinduced single electron transfer. Specifically the release of carboxylic acids phenacyl and 4-N-alkylpicolinium esters have been examined. An example of one such reaction is shown below.
These reactions have recently been applied to the development of phototriggering reagents that can rapidly and reversibly alter the viscosities of bulk liquids by catalyzing self-assembly processes. For example, visible light triggered photorelease of cinnamate ions in the presence of CTAB micelles has been shown to convert the latter from spherical structures into elongated worm-like structures. This in turn causes the solution to convert from a free flowing fluid to a gel-like state.
A second area is the study of reactive intermediates including nitrenium ions and ion diradicals. Recent computational studies from the PIs group have shown that when electron negative centers (nitrenium ions, carbenium ions, etc) are substituted on a benzene ring with strong donors in the meta position low energy triplet diradical states are formed. Current studies are aimed at experimentally generating and characterizing this new class of reactive intermediates using laser flash photolysis product analysis and other methods.
More recent studies have been directed at the discovery and characterization of catalysts capable of capturing CO2 from power plant emission streams and then utilizing solar energy to effect a net transfer of electrons from water to CO2 to make formic acid, methanol or other reduced products. These latter products could be recycled as fuels or used as feedstocks for the synthesis of polymers or other high value materials.