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 problem-solving. A program to inspire underrepresented high school students to pursue careers in science, which takes advantage of Tucson’s large Hispanic and long-standing Native American populations (two minorities woefully underrepresented in science), is an integral part of this endeavor.

SUMMER PROGRAM IN HYDROGEN RESEARCH

FOR HIGH SCHOOL STUDENTSJune 5-July 14, 2006

The CRC Hydrogenase TeamSynthesis:

Professor Richard Glass (Co-PI)Dr. Jinzhu Chen (Postdoc)Dr. Rudresha Kottani (Postdoc)

Ms. Uzma Zakai (Graduate Student)Mr. Matt Swenson (Graduate Student)

Electrochemistry:

Professor Dennis Evans (Co-PI)

Dr. Greg Felton (Postdoc)

PES/Computations:

Professor Dennis Lichtenberger (Co-PI)Ms. Tori Moser (Graduate Student)Mr. Taka Sakamoto (Graduate Student)Mr. Aaron Vannucci (Graduate Student)Mr. Ben Petro (Graduate Student)

The PromiseHydrogen as our energy source benefits us because it is renewable,environmentally friendly and removes our dependence on foreign oil.

The ChallengeTo 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.

The IdeaTo 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 directly to a simple chemical analogue of the diiron active sitethe 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.

2H2 + O2 2H2O + Energy

CysS

FeFeCO

CN

SS

CO

CO

CN

2e-

2H+

Fe-Hydrogenase

H2

computations

synthesiselectrochemistry

Richard S. Glass, Dennis H. Evans, and Dennis L. LichtenbergerThe University of Arizona

Diiron active site

The NSF “Nugget”:

Hydrogenase Active Site

http://metallo.scripps.edu/PROMISE/FEHASE.html

X = OH¯ or H2O; Y = O or N

Quinone Derivatives

• Quinone/Hydroquinone derivatives of the disulfidocompound are of special interest because of their potential redox properties.

-2 H + , -2 e -

+ 2 H + , + 2 e -S S

Fe FeCO

COCOOC

OC

OC

OHOH

S S

Fe FeCO

COCOOC

OC

OC

OO

Ms. Uzma Zakai

Warmup: “Fp”-Dimer, [(5-C5H5)Fe(CO)2]2

300

250

200

150

100

50

0

-50

-100

-1.25 -1.5 -1.75 -2 -2.25 -2.5E(V):

I/µA

2.07 mM Fp2

with increasing amounts of acetic acid.

[(-C5H5)Fe(CO)2]2 + 2e-

2(-C5H5)Fe(CO)2-

(-C5H5)Fe(CO)2H + e-

(-C5H5)Fe(CO)2H-

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 RESEARCHFOR 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

Sabino High School

William Pickeral

University High School

Sarena Debaca

Sunnyside High School

Stefan Romero

Sunnyside High School

Jessica Peña

Desert View High School

Delissa Fimbres

Palo Verde High School

Wilma Amero

Pueblo Magnet High School

Tim Barry

Salpointe Catholic High School

Mark Calhoun

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

Before UV light

After UV light

.20 grams of iron backbone, .19 grams of quinone, and 250 mL of .20 grams of iron backbone, .19 grams of quinone, and 250 mL of THF.THF.

The UV light was on for a total of 7.5 minutes.The UV light was on for a total of 7.5 minutes.

This is not supposed to happen

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

Team: Barry, Debaca, Romero

Photo-electronic and Computational Analysis of Various

Geometries of a Non-bridging HydrogenaseModel

Delissa Fimbres

Mark Calhoun

William Pickeral

7/14/06Cd crc/adf cp feb2 adf pico adf.out $ADFFBIN/densf.out <densf.in> densf.out $ADFBIN/dmpkf TAPE 41 > HOMOA1.t41 cd .. Ctlr w ctrl x mkdir fe4 cd pico mk cp crc/adf

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!