Excited State Proton Transfer from Acidic Alcohols to a Quinoline Photobase Can Be Solvated by Non-Acidic Alcohol Solvents.

Photobases are a type of molecule that become more basic upon photoexcitation and can therefore be used to control proton transfer reactions with light. The solvation requirements for excited state proton transfer (ESPT) in photobase systems is poorly understood, which limits their applicability. Here, we investigate the solvation of the ESPT reaction using 5-methoxyquinoline (MeOQ), a well-studied photobase with an excited state p (p) of approximately 15.

Modeling and Characterization of Exciplexes in Photoredox CO Reduction: Insights from Quantum Chemistry and Fluorescence Spectroscopy.

Interactions between excited-state arenes and amines can lead to the formation of structures with a distinct emission behavior. These excited-state complexes or exciplexes can reduce the ability of the arene to participate in other reactions, such as CO reduction, or increase the likelihood of degradation via Birch reduction. Exciplex geometries are necessary to understand photophysical behavior and probe degradation pathways but are challenging to calculate.

Kinetic Evidence for the Necessity of Two Proton Donor Molecules for Successful Excited State Proton Transfer by a Photobase.

Photobases are molecules that convert light to proton transfer drive and therefore have potential applications in many areas of chemistry. Previously, we studied the photobasicity of quinolines and explored their applications. While it is possible to tether a photobase near a target proton donor, for the sake of versatility it is desirable to explore their capability to deprotonate molecules dispersed in a solution.

Donor-acceptor preassociation, excited state solvation threshold, and optical energy cost as challenges in chemical applications of photobases.

Photobases are molecules with increased pKa in the excited state that can serve to transduce light energy into proton removal capability. They can be used to control chemical reactions using light, such as removing protons from a catalytic site in reactions that are rate-limited by proton transfer. We identify and explore several major challenges toward their practical applications.

Photodriven Deprotonation of Alcohols by a Quinoline Photobase.

Control of proton transfer is relevant to many areas in chemistry, particularly in catalysis where the kinetics of (de)protonation reactions are often rate limiting. Photobases, which are molecules with enhanced basicity in the excited state, allow for control of proton transfer with light and have the potential to be used as functional units in catalytic systems. Alcohols are the feedstock in many catalytic reactions, where their deprotonation or dehydrogenation is often important.

Proton Capture Dynamics in Quinoline Photobases: Substituent Effect and Involvement of Triplet States.

Converting light into chemical energy often occurs through redox reactions that require transfer of several electrons and protons. Using light to control proton transfer has the potential for driving otherwise unfavorable protonation reactions or producing transient pH changes. Photoacids and photobases are fundamental functional elements that could serve this purpose.