I-APS Awards: David G. Whitten
Several weeks ago it was announced that David Whitten will
receive the 1998 IAPS award in photochemistry at the Winter
Conference in January, 1998. Dave (as he is known by most of
his friends and acquaintances) is my Ph.D. research mentor
and friend; therefore, it is natural that I write a short
biography of him in honor of his award.
Dave was born in Washington, DC and raised in the Baltimore,
MD area. He attended Johns Hopkins University and received a
B.S. in Chemistry in 1959. He remained at Johns Hopkins for
his Ph.D. which he completed under the direction of Prof. A.
H. Corwin. Dave's Ph.D. research set the stage for one of
the areas where his research has had a large impact over the
years -- the spectroscopy of porphyrins and
metalloporphyrins. While in graduate school Dave found time
for some pursuits outside of the laboratory -- he married Jo
Wright. After completing his Ph.D. in 1963 Dave and Jo moved
to Pasadena, California where Dave first worked as a U.S.
Army officer (assigned to NASA) at the Jet Propulsion
Laboratory. Some of Dave's work at JPL reflected his
continued interest in porphyrin chemistry, but he also
worked on projects related to applications of mass
spectrometry to planetary science. After his two year stint
with the Army at JPL, Dave was an NIH postdoctoral fellow in
George Hammond's group at CalTech. At CalTech, among other
projects related to organic photochemistry, Dave carried out
studies which explored the correlation between the outcome
of reactions induced by ionizing radiation and UV
photolysis.
Dave began seeking academic positions and received several
offers, including one from the University of North Carolina
in Chapel Hill. Although he had some "trepidation" about
moving into the "deep south", Dave accepted the position in
the Fall of 1966 at North Carolina as an Assistant Professor
of Organic Chemistry. Dave began his independent academic
career by going back to his roots -- he initiated detailed
studies of porphyrin photochemistry. During the early years
Dave's group focused on examining energy and electron
transfer processes ensuing from the singlet and triplet
excited states of various metalloporphyrins. This work on
porphyrin photochemistry and photophysics formed the core of
Dave's first publications from Chapel Hill, and has been a
recurring theme in his research throughout his entire
career. Dave was also quite interested in the photochemistry
of nitrogen aromatics; in particular his group published a
number of papers on the photochemistry of the aza stilbene
analogs (4-pyridyl)-2-phenylethylene and l,2-
bis(4-pyridyl)ethylene. This work was a prelude to his idea
to use paraquat as an electron acceptor in excited state
electron transfer reactions with transition metal complexes
(see below).
About 3 or 4 years after starting at Chapel Hill, Dave
joined forces with another young Professor, Thomas Meyer,
and the two began collaborative investigations on the
mechanism by which various organic and inorganic species
quench the luminescent metal-to-ligand charge transfer
excited state of Ru(bpy)32+. This collaboration was a
natural for the two groups -- Dave had already amassed a
significant background in photoinduced electron transfer
reactions through his work on the porphyrins and the
nitrogen heterocycles, while Tom had a great deal of
expertise with electron transfer and spectroscopy of
inorganic complexes. Before Whitten and Meyer began working
together on the photoinduced electron transfer problem,
Gafney and Adamson, among others, had reported that various
metal ion quench the luminescence from Ru(bpy)32+; however,
there wasn't any definitive evidence that the quenching was
due to photoinduced electron transfer. In the first of a
series of publications on the topic, Meyer and Whitten used
conventional flash photolysis to demonstrate that the one
electron reduced form of paraquat is produced as a result of
the interaction of photochemically excited Ru(bpy)32+ and
ground state paraquat. This paper, which appeared in 1974,
was the first to provide unequivocal evidence that the
charge transfer excited state of Ru(bpy)32+ engages in
photoinduced electron transfer reactions. The 1974
communication was followed shortly by a series of papers
demonstrating that Ru(bpy)32+ undergoes photoinduced
electron transfer with a variety of organic donors and
acceptors. Although other research groups clearly played an
important role in the development of Ru(bpy)32+
photochemistry, it is clear that the early work on
photoinduced electron transfer done by the Meyer-Whitten
collaboration set the stage for the vast amount of research
that was subsequently carried out on the application of
metal complexes to photoinduced electron transfer and
photochemical conversion of solar energy.
Dave Whiten has also made significant contributions to the
area of the chemistry of organized assemblies. Dave's
interest in this area began during a sabbatical year
(supported by a Humboldt Fellowship) in 1975 with Hans Kuhn
at the Max-Planck-Institut f�r Biophysikalische Chemie in G�ttingen,
Germany. While in Germany, Dave studied the cis-trans
photoisomerization of surfactant thioindigo dyes
incorporated into multilayer assemblies that were fabricated
using the Langmuir-Blodgett technique. Upon returning to
Chapel Hill, Dave established a Langmuir-Blodgett monolayer
trough in his laboratory and began working actively in the
area of exploring photophysics arid photochemistry in
monolayer and multilayer assemblies. Some high points of his
work on Langmuir-Blodgett monolayer and multilayer
assemblies include his studies of the photophysics of a wide
variety of surfactant stilbene derivatives in multilayer
assemblies. Dave's interest in monolayers and multilayers
led him to begin exploring phototophysics and photochemistry
in other organized assemblies including micelles, vesicles
and microemulsions. In this work Whitten effectively
combined his interests in organic photochemistry, porphyrin
photochemistry and photoinduced electron transfer to produce
a large body of insightful work which provided a great deal
of information regarding the structure and properties of
organized assemblies.
While all of this research was going on in the laboratory
Dave's academic career had been moving forward at a fast
pace. He was promoted to Full Professor at UNC in 1973 and
then was promoted to M. A. Smith Professor of Chemistry in
1980. In 1983 Dave decided to leave Chapel Hill and move to
Rochester, NY where he assumed the C. E. Kenneth Mees
Professorship in Chemistry at the University of Rochester.
Some impetus for Dave's move to Rochester was the potential
for initiating collaborations with industrial scientists
interested in the photosciences -- indeed Rochester has been
at the forefront of applied photosciences for a over a
century in part due to the presence of Kodak, Bausch and
Lomb, and Xerox, among other companies. Shortly after
moving, Dave and his colleagues at Rochester, in
collaboration with groups from Kodak and Xerox were
successful in obtaining funding from the National Science
Foundation to establish the Center for Photoinduced Charge
Transfer. Dave was selected to act as the Director of the
Center, and he held this position from 1989 - 1995. During
Dave's tenure at Rochester he also served as Chairman of the
Chemistry Department from 1988 - 1991 and again from 1995 -
1997.
While at Rochester Dave's research group continued to study
photochemistry in organized assemblies as well as the
reactivity of organic radical ions that are produced by
photoinduced electron transfer. A relatively recent research
emphasis emanated from Dave's earlier work on surfactant
stilbene derivatives in monolayers and vesicles. Early on
Whitten and co-workers noticed that when incorporated into
monolayer assemblies, stilbene chromophores exhibit be
spectroscopic signature of H-aggregates. This early
observation has been elaborated upon in more recent studies
of vesicles consisting of phospholipid molecules that
contain stilbene, azobenzene and squaraine chromophores. The
recent vesicle work indicates that a variety of stilbene-shaped
chromophores form a chiral tetramer (a "pinwheel" aggregate)
when they are incorporated into a vesicle bilayer. Quite
interestingly, the experimental work on the chiral
aggregates is strongly supported by computer simulations of
stilbene aggregate structure that have been carried out by
Jerry Perlstein at the Center for Photoinduced Charge
Transfer.
Very recently Dave has embarked on yet another new adventure
in science. In August of this year he moved from Rochester
to the Los Alamos National Laboratory in New Mexico. While
it is yet unclear how the new environment will influence his
research, it is likely that Dave will successfully harness
the strengths of Los Alamos in the areas of biological and
materials chemistry to continue his work in the area of
chemistry at interfaces and in organized assemblies.
Dave's scientific, academic and administrative
accomplishments have been recognized by many awards which
include an A. P. Sloan Fellowship, the Humboldt Fellowship,
the Japan Society for Promotion of Science Fellowship, the
ACS Award in Colloid and Surface Chemistry, and two NSF
Awards for Special Creativity. He recently accepted the
position as Editor-in-Chief of the ACS publication Langmuir,
and he will manage the journal from his new office at Los
Alamos.
While it is clear that Dave Whitten is a most accomplished
scientist and academician, people who know him recognize
that his most admirable trait is his personality. Dave is a
very outgoing person -- he possesses a keen sense of wit,
and he has a broad range of interests that include history,
art, music, pop culture and the climate. Furthermore, those
who share any amount of time with Dave know very well that
there is only one thing more important to him than his
science -- and that is the sport of running. Dave is a very
accomplished runner, literally having logged tens of
thousands of miles running in every country and terrain
imaginable. He typically runs 50 - 70 miles per week and
competes in 3 - 4 marathons per year, and when he competes,
he usually finishes among the top in his age group. Indeed,
several years ago he was ranked 3rd in the nation among
marathon runners in his age group.
It is quite clear that Dave Whitten is a leader in every
respect. It is most fitting for him to receive the IAPS
award in photochemistry and I take this opportunity to
congratulate him on his past accomplishments and wish him of
luck with his future endeavors.
Kirk Schanze
Department of Chemistry
University of Florida
November, 1997
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