2018

Major Projects

Chemical reactivity promoted by electron transfer is one of the major areas of chemistry. Strong neutral electron donors, termed "super-electron-donors", are characterized by low ionization energies and very negative oxidation potentials (E1/2 values beyond –1 V vs. SCE). Among the advantages cited for these electron donors is the ability to (1) modulate their redox potentials and reactivity by structural modifications, (2) tune their selectivity, (3) use them as pure compounds in appropriate quantities, (4) operate under mild conditions, (5) carry out reactions in organic solvents, (6) attach them to solid supports, and (7) regenerate them after use. The inherently most powerful neutral molecule electron donors yet known, as evidenced by our photoelectron measures of the extremely low gas-phase ionization energies and our electrochemical measures of extremely negative oxidation potentials, are the dimetal tetraguanidinate complexes of type shown in the Figure at left.
   

Electrocatalysis

The reduction of protons to molecular hydrogen is one of the most fundamental electrocatalytic processes, and the development of efficient electrocatalysts for this process is of great industrial and environmental importance. This research develops a new class of improved electrocatalysts for molecular hydrogen (H2) generation that harnesses proton-coupled electron transfer (PCET) assisted catalysis using [2Fe-2S] complexes ([Cat]) and acidic proton donors (HA) (see Figure at right). The research leverages our very recent findings that certain butterfly [2Fe-2S] complexes exhibit exceptionally fast rates  (106-108 molecules of hydrogen produced per molecule of catalyst per second) for electrocatalytic hydrogen evolution reactions (HER) at low overpotentials. These extraordinary findings are being exploited  to develop [2Fe-2S] cluster-based electrocatalysts for improved performance in the HER.