Transcript Research as a Driver of Educational Innovation: Some Reflections on the Outreach Program of an NSF Collaborative Research in Chemistry Project Dennis H.

Research as a Driver of Educational
Innovation: Some Reflections on the
Outreach Program of an NSF
Collaborative Research in Chemistry
Project
Dennis H. Evans
Department of Chemistry, University of Arizona,
Tucson, AZ 85721 (USA)
Supported by NSF, CHE-0527003
…or, how I spent my summer
vacation (seriously)
J. Am. Chem. Soc. 1984, 106, 3039-3041.
National Science Foundation
Collaborative Research in Chemistry
“Coupling Redox Processes to Drive Chemical Reactivity: New Catalysts for
Hydrogen Production”
Principal Investigators: Dennis H. Evans, Richard S. Glass and Dennis L. Lichtenberger,
Department of Chemistry, University of Arizona
The science:
…To overcome these obstacles, this proposal derives inspiration from Nature.
Hydrogenases are naturally occurring enzymes that couple low potential redox
reactions to generate hydrogen. Iron-only hydrogenases utilize a cheap and
abundant metal and operate in ambient conditions. The active site in the enzyme
is a diiron center. The scientific challenge is to couple low potential redox
reactions with reduction of a diiron center, an energetically unfavorable process.
The proposed solution is to electronically couple a functional diiron system to a
low potential redox ligand, and then drive the energetically unfavorable
electron-transfer from the redox ligand to the diiron system by coupling it to an
irreversible chemical reaction, that is, protonation and generation of H2…
The outreach:
…be mentored in the skills essential for
multidisciplinary team approaches to problemsolving. A program to inspire underrepresented high
school students to pursue careers in science, which
takes advantage of Tucson’s large Hispanic and longstanding Native American populations (two
minorities woefully underrepresented in science), is
an integral part of this endeavor.

SUMMER PROGRAM IN HYDROGEN RESEARCH
FOR HIGH SCHOOL STUDENTS
June 5-July 14, 2006
The CRC Hydrogenase Team
Synthesis:
Professor Richard Glass
Dr. Jinzhu Chen
Dr. Rudresha Kottani
Ms. Uzma Zakai
Mr. Matt Swenson
Electrochemistry:
Professor Dennis Evans
Dr. Greg Felton
PES/Computations:
Professor Dennis Lichtenberger
Ms. Tori Moser
Mr. Taka Sakamoto
Mr. Aaron Vannucci
Mr. Ben Petro
(Co-PI)
(Postdoc)
(Postdoc)
(Graduate Student)
(Graduate Student)
(Co-PI)
(Postdoc)
(Co-PI)
(Graduate Student)
(Graduate Student)
(Graduate Student)
(Graduate Student)
The NSF “Nugget”:
Richard S. Glass, Dennis H. Evans, and Dennis L. Lichtenberger
The University of Arizona
Fe-Hydrogenase
The Promise
Hydrogen as our energy source benefits us because it is renewable,
environmentally friendly and removes our dependence on foreign oil.
The Challenge
To make a hydrogen energy economy a reality major obstacles must be
overcome that require new scientific knowledge. One such obstacle is the
need for cheap, efficient, readily available catalysts for chemically
combining two electrons (2e-) and two protons (2H+) from water to produce
molecular hydrogen (H2) as well as catalysts for the burning of H2 in fuel
cells to yield energy and water.
Diiron active site
computations
synthesis
electrochemistry
The Idea
To invent a catalyst we have been inspired by nature's catalyst,
hydrogenase. As illustrated, Fe-hydrogenase is a complex protein which
bears a catalytic core, the diiron active site, and electron transfer centers
connecting the buried core to the electron donors at the protein surface. By
directly attaching a versatile and easily made electron donor
OC
C
N
Fe
Fe
C
O
CN
C
O
2e2H+
directly to a simple chemical analogue of the diiron active site
the need for protein and electron transfer centers vanishes. As
shown, two electrons (2e-) enter the donor site, which then
delivers them to the catalytic diiron site to combine with 2H+ to
produce H2. This design requires new basic scientific knowledge because
the internal 2e- transfer requires a conduit, a driving force to propel them
energetically uphill, and the 2H+ must be delivered selectively at the diiron
site to rapidly form H2. Spectroscopic and electrochemical data on the
chemically synthesized catalyst candidates will afford the real-world
measurements and the essential scientific understanding required for
inventing a successful catalyst.
S
S
S
Cys
H2
2H2 + O2
2H2O + Energy
Hydrogenase Active Site
X = OH¯ or H2O; Y = O or N
http://metallo.scripps.edu/PROMISE/FEHASE.html
Quinone Derivatives
• Quinone/Hydroquinone derivatives of the disulfido
compound are of special interest because of their
potential redox properties.
HO
OH
O
O
-2H+, -2eS
S
+2H+, +2e-
OC
Fe
OC
OC
Fe
CO
S
CO
OC
CO
OC
Fe
OC
S
Fe
CO
CO
CO
Ms. Uzma Zakai
Warmup: “Fp”-Dimer, [(5-C5H5)Fe(CO)2]2
(-C5H5)Fe(CO)2H + e(-C5H5)Fe(CO)2H-
I/µA
300
2.07 mM Fp2
with increasing
amounts of
acetic acid.
250
200
150
100
50
[(-C5H5)Fe(CO)2]2 + 2e2(-C5H5)Fe(CO)2-
0
-50
-100
E(V):
-1.25
-1.5
-1.75
-2
-2.25
-2.5
Felton, Glass, Lichtenberger and Evans, Inorg. Chem. 2006 (ASAP, 08/23/06, 10.1021/ic60984e)
Cover Art for
Inorganic
Chemistry —
are we ready for
this?
He 1 close comparison
11
10
9
8
Ionization Energy (eV)
Ms. Tori Moser, 2006
SUMMER PROGRAM IN HYDROGEN RESEARCH
FOR HIGH SCHOOL STUDENTS
June 5-July 14, 2006
Recruit high school students and teachers for a six-week
program of research in the CRC laboratories
•
• Concentrate on Tucson high schools (e.g., Sunnyside High
School is >80% Hispanic)
• Students and teachers will receive a stipend; 5 days/week, 8
hr/day
• Form teams of two students and one teacher
• The teams will work with the faculty, postdocs and graduate
students in the CRC on projects of direct importance to CRC
• At the end, each team will write a report and prepare a
presentation
Questions
•
•
•
•
•
•
•
•
Will anyone apply?
(25 students; 3 teachers)
Qualifications?
(Excellent)
Will the students understand?(Mixed)
Will teachers want to spend the summer with
students?
(No problem)
Shall we start with a week of lectures on the
hydrogen economy, relevant chemistry…?
(Bored them to death)
Shall we have exercises to introduce the students to
laboratory techniques?
(Essential)
Will the laboratory projects be interesting?
(They loved it)
What will motivate them?
(Feeling that they are
helping the project)
Thu Nguyen
William Pickeral
Sarena Debaca
Sabino High School
University High School
Sunnyside High School
Stefan Romero
Jessica Peña
Delissa Fimbres
Sunnyside High School
Desert View High School
Palo Verde High School
Wilma Amero
Tim Barry
Mark Calhoun
Pueblo Magnet High School
Salpointe Catholic High School
Sabino High School
The projects and presentations:
• Amero, Nguyen, Peña: Optimization of chemical synthesis of
quinones
• Barry, Debaca, Romero: Development of an electrochemical
method of preparing quinones
• Calhoun, Fimbres, Pickeral: Computational study of a new
hydrogenase mimic
Adding Quinone To Backbone
.20 grams of iron backbone, .19 grams of quinone, and 250 mL of
THF.
The UV light was on for a total of 7.5 minutes.
Before UV light
After UV light
This is supposed
to happen
Starting at Neutral pH with 70
Coulombs to complete
Reaction
Color is Red
At about 30 coulombs
and an Acidic pH
Instantaneous Color
Change to Green
This is not
supposed to happen
Team: Barry, Debaca, Romero
Photo-electronic and
Computational Analysis of Various
Geometries of a Non-bridging
Hydrogenase Model
Delissa Fimbres
Mark Calhoun
William Pickeral
7/14/06
So what did we learn?
• The students had very minimal prior laboratory experience, but
they loved the lab
• We shouldn’t start with a week of lectures
• The teams are capable of developing their own ideas
(electrosynthesis of quinones was suggested by Tim Barry)
• Six graduate students and one postdoc were assigned to work
with the participants. This was of crucial importance
• Our expectations of prior knowledge of chemistry were
unrealistically high
THANK YOU VERY MUCH
CRC (Collaborative Research in Chemistry)
PROGRAM!