1. Dependence of Rates of Interfacial Electron Transfer on Anchoring Group Structure and Dye MLCT State Energy
Debra L. Mohler, Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, VA 22807
We have determined via femtosecond IR spectroscopy (left, in collaboration with Professor Tianquan Lian at Emory University) that electron transfer from bipyridinechlororhenium tricarbonyl complexes was significantly affected by anchoring group; and surprisingly, the thiol group gave the lowest ET rate.
We have also prepared bripyridinechlororhenium tricaarbonyl complexes with flexible tethers of varying length (below left) and with rigid tethers and tripod anchoring groups (middle/top right, below) for distance-dependence studies, and we are currently synthesizing similar tripod molecules with a perylene dye (middle/lower right, below) for single molecule ET studies.
Comparison of electron transfer kinetics from Re(Lx)(CO)3Cl [Lx=2,2’-bipyridine-4,4’-CH2X, X=COOH, PO3H2 and SH] to a TiO2 electrode.
Interfacial electron transfer (ET) from molecular adsorbates and metal or semiconductor nanoparticles/thin films is an essential process in applications including photocatalysis, solar energy conversion, and photography. The emerging field of heterogeneous photocatalysis is of particular interest for its potential to employ “green” methods in functionalizing petroleum-derived materials and in developing new synthetic methods. Because the rate of ET is often a key determinant of efficiency in these systems, the understanding of this process is essential for their design.