South Texas Section

Local Section of the American Chemical Society

September 2017 Meeting


Hydrogenase- and ACS-Inspired Bioorganometallic Chemistry

Marcetta Y. Darensbourg

Department of Chemistry, Texas A&M University

College Station, TX


Enzyme active sites such as the [FeFe]- and [NiFe]-H2ases, as well as Carbon Monoxide Dehydrogenase and Acetyl coA Synthase, ACS, have inspired chemists to use well-established principles and synthetic tools of organometallic chemistry in the development of biomimetics.  The usual purpose of such studies is to understand how first-row transition metals are rendered by nature into molecular catalysts that perform as well as noble metals in H+/H2 or CO/CO2 interconversions.  In fact, the active site of the diiron hydrogenase, initially “crudely” modeled by (µ-pdt)- or (µ-adt)[Fe(CO)2(CN)]2= , is now known by the work of Berggen, et al. to readily insert into apo-proteins, generating in the case of the  (µ-adt)[Fe(CO)2(CN)]2= model complex, a fully functional enzyme.  Here we come to the astounding conclusion that not only were the synthetic “model builders” on the right track, the model is actually the essential natural catalyst!  [Nevertheless, we continue to be humbled by the essential role of the protein environment that turns on the remarkable activity of these small diiron complexes.]   Other processes, also involving the cyano-diiron complexes, are of importance to the development of biohybrid chemistry. Hence possibly the oldest catalytic chemistry on earth asks new fundamental questions that organometallic chemists might address.  This lecture will describe our synthetic and mechanistic approach that draws concepts from three active sites in order to define the requirements of iron-containing proton reduction electrocatalysts.  In particular we have developed mono- and dinitrosyliron complexes for building thiolate-S bridged redox active units that provide “soft landings” for the two electrons required to be added into FeFe’ and NiFe bimetallics along with protons.


Texas A&M University-Corpus Christi    Engineering Building     Room EN-106
6300 Ocean Dr., Corpus Christi, TX. 78412

On the campus map, the building number is 15. This building is right next to BAYSIDE PARKING GARAGE.
The GPS coordinates for the Parking Garage are 27.713836, -97.326423
The GPS coordinates for the Engineering building are 27.712697, -97.325709 [Note you cannot drive di-rectly to the engineering building).

5:45 – 6:30 pm: Introduction to Student and Faculty who are present, ACS Local business can also be done at this time.
6:30 – 7:15 pm: Talk
7:15 – 7:30 pm: Questions
7:30 – 8:00 pm: Tour of building or Q&A with students and/or faculty