A family of diiron, dithiol compounds based on Fe2(�-S2C3H6)(CO)6 has been found to structurally mimic the active site of [FeFe]-hydrogenases, which catalyze the reduction of hydrogen, and are being explored because of this potential.  In this research, the time-dependent behavior of Fe2(�-S2C3H6)(CO)6 and Fe2(�-S2C2H4)(CO)6 is observed using ultrafast UV-pump/IR-probe measurements of the carbonyl region.  When Fe2(�-S2C3H6)(CO)6 is pumped with 266 nm, there primarily exist absorptions lasting on a relatively long timescale, corresponding to the loss of a CO ligand.  In the 355 and 532 nm data, there are additional short-lived absorptions corresponding to either the lengthening of the Fe-Fe bond or a long-lived excited state.  Fe2(�-S2C2H4)(CO)6 data closely resembles that of Fe2(�-S2C3H6)(CO)6 with less intense short-lived absorptions, a result of the additional constraint caused by the shorter disulfur bridge.  These results suggest that excitation can cause structural changes that could interfere with proposed mechanisms for hydrogen reduction.

Time-resolved vibrational spectroscopy of [FeFe]-hydrogenase active site model compounds

243rd National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.