Interview with Steven Pedersen, Organic Chemistry Lecturer, Director of the College of Chemistry Health and Safety Program
Number: 00S09. Issue: Spring 2000
Author[s]:
Nahal Lalefar, Jane Lo, Heather McGee, Viet Nguyen, Shivani Sethi, and Ann Tsai (Photographs by Charity Kirk)
Keywords:
Abstract:
Synthetic chemistry has been a major part of Dr. Steven Pedersen?s life for over 20 years. After completing his graduate and postdoctoral studies at the Massachusetts Institute of Technology, he came to Berkeley and designed an organometallic reaction that is often referred to as the Pedersen reaction.
As an organic chemistry lecturer and the Director of the College of Chemistry Health and Safety Program, Dr. Pedersen has helped redesign the undergraduate chemistry lab curriculum. By developing micro-scale experiments that use benign solvents and alternative reagents, he has promoted the philosophy of green chemistry, which is safer for students, less expensive for the department, and friendlier to the environment.
He feels that he has found a good balance between his full-time teaching position and his family, a wife of 16 years and two children, ages 11 and 14.
Since 1985, Dr. Pedersen has taken a subject that is rumored to be dry and full of memorization and made it come alive to over 500 students each semester. He strives to present a difficult subject in a challenging manner, yet always takes the time to incorporate real-life examples into his lectures.
Students appreciate his approachable attitude and good-natured personality, and see in him all the qualities of a true role model: someone who leads a happy, well-balanced life, loves what he does, and spreads this enthusiasm to others.
BSJ: What specifically was involved in your past research in
organometallics?
Dr. Pedersen: My research group focused on using transition
metals to promote the stereoselective formation of carbon-carbon bonds. Specifically, we used early transition
metals to carry out reductive coupling reactions. For example, such a reaction can be used to bring two carbonyl
functions together to make a vicinal diol.
At the time, our methodology was unique in that it allowed one to carry
out the reaction such that only one major diastereomer was formed in any given
reaction. In a nutshell, that is what
we did. It was a lot of fun for several years but I am not involved in that
area anymore.
BSJ: Why is it you decided to stop?
Dr. Pedersen: I felt it was time for a change. I became more
involved in teaching and saw a need for more innovation in the area of the
undergraduate organic chemistry laboratory curriculum and for improvement of
our laboratory physical plant, that is, our actual facilities. There are probably 15 or 20 organic
chemistry laboratory texts on the market, none of which I felt were serving the
general population of undergraduates in organic chemistry all that well. The majority of texts focused on
"older" chemistry and contained experiments that were based on the
"cookbook" approach, where you are told exactly what to do and
exactly what you will get.
I have
found that students are far more receptive to discovery based experiments,
where they actually figure out a puzzle based on experimental data acquired in
the lab. At the same time, the students
are drawing a connection between lecture and laboratory. As I started to develop new experiments for
our courses, I found it to be quite challenging. I also try to develop experiments that help keep students abreast
of the newest trends and methods in organic chemistry. History is important,
but it is just as important to keep moving on, to generate our own history.
BSJ: We understand you have a reaction involving
organometallics named after you: the Pedersen reaction. Can you tell us about
the reaction and how you developed it?
Dr. Pedersen: I have heard it called that before, but I am
not sure how often it is referred to as such. It stemmed from the area of
reductive coupling that I previously mentioned. The reaction was something that
I proposed to do before arriving at Berkeley.
However, as it turned out, we were able to tweak it to become far more
useful than originally proposed.
BSJ: As director of the College of Chemistry Health and
Safety Program, what are your responsibilities and duties? What is it that the
program strives to achieve and is in charge of as a group?
Dr. Pedersen: My responsibilities include overseeing an
operation that has two full-time and several variable time employees. Obviously it is a relatively small group of
very capable, hard working staff. Yet
our responsibilities are extremely important.
Our goal is to help maintain a safe and healthy workplace for our
researchers, staff and students.
We have
several mechanisms in place for achieving this goal. These include inspections of our facilities, providing safety training
in a wide variety of areas, maintaining all records and programs required by
law, and dealing with the day to day safety issues that arise in a chemistry
complex housing over 1000 employees.
Additionally, when one considers that 3,000-4,000 undergraduates pass
through our teaching laboratories every year, the importance of our group
becomes even more pronounced.
BSJ: So you were one of the key players who revamped the
whole Chemistry 3 lab curriculum?
Dr. Pedersen Yes, Dr. Arlyn Myers and myself. I was asked to work on the Chemistry 3A
laboratory curriculum and she worked on the Chemistry 3B curriculum at the
time. Since then we have traded responsibilities for the courses. However, the new experiments I design are
used in both courses as well as in Chemistry 112. One of the
major improvements we made when changing the lab curriculum was to purchase
microscale laboratory equipment. This was a large effort but it has really
turned out to be beneficial in several areas.
For example, working with smaller amounts of chemicals provides a safer
working environment for the students.
Furthermore, we generate approximately 25 times less waste than a
traditional macroscale course. This is
of course not only helpful to the environment, but also significantly reduces
the amount of money our College spends on the disposal of chemical waste. Another overlooked benefit of
microscale chemistry is the reduced wear and tear on our facilities. For example, working surfaces last much
longer when they are not subjected to accidental spills of large volumes of
chemicals.
BSJ: It has been said that some of the products we obtain in
lab are reused in some of the other labs.
Dr. Pedersen: That?s correct. This has required some coordination of the curricula of both
Chemistry 3A and 3B as well as Chemistry 112.
That is, we attempt as often as possible to develop experiments where
the products can be used as starting materials for another experiment in either
the same or a different course.
Initially, I received a Hazardous Waste Minimization Grant funded by the
campus, to develop the idea.
We are
constantly looking for new ways to incorporate this philosophy into our
experiments. For example, in Chemistry
3A and 112A, students perform a Grignard reaction to make 1,
1-diphenylethanol. In Chemistry 3A,
the students use this for another reaction later in the course. In 112A, the product is collected and used
in Chemistry 3B.
BSJ: Have any other schools adopted your curriculum? Other
UC schools?
Dr. Pedersen: Several people around the country have used
some of our experiments at one time or another. At this time, I am not aware that any of the other UC?s have used
our experiments. The way this works is
generally word of mouth. I will pass on
an experiment to a friend at another College.
If they like it, they tell others and before you know it, several people
are using it.
BSJ: Are the majority of schools in the nation still on the
macro-scale?
Dr. Pedersen: I do not know the exact numbers. However, I
would guess that half of the schools have gone to micro-scale and the other
half are somewhere between macro and micro, sometimes referred to as
mini-scale. Basically mini-scale uses
smaller versions of macroscale equipment.
BSJ: Have you found that research companies or labs that do
research have incorporated this micro-scale ideology?
Dr. Pedersen: More so now than 10 years ago. The reasons are
two-fold: economics and advances in technology. The cost of disposing waste is
significant nowadays and the smaller scale you work on, the less waste you
generate. Advances in analytical
chemistry, especially the analysis of small quantities of products, have also
allowed chemists to work on a smaller scale.
The whole field of combinatorial chemistry, the process of rapidly
generating small quantities of hundreds of analogous molecules, relies
extensively on new analytical methodology.
BSJ: Was your own reaction developed on the micro or macro
scale?
Dr. Pedersen: The scale we used would be considered
mini-scale. However, industry has
scaled up our reaction to the multi-kilogram level when they were interested in
using it to synthesize a promising HIV protease inhibitor.
BSJ: What is Green Chemistry and how does that relate to
laboratory experiments and science in general?
Dr. Pedersen: Green chemistry is a term coined by the
current administration in Washington, but it should really be considered a
philosophy since administrations come and go.
In essence, it is an approach to synthetic chemistry that aims to
minimize or completely eliminate the generation of hazardous waste.
Several
approaches exist. For example, one can
develop or use existing reagents that are less harmful than those used in the
past. Another approach makes use of
benign solvents, solvents that can be disposed of without great risk to the
environment. Water and ethanol are good
examples. Our first step towards
"greener" undergraduate labs was the incorporation of microscale
equipment, which I just discussed.
Another approach has been in the area of alternative reagents. For example, we often use Amberlyst-15, an
acidic resin, in place of sulfuric acid.
This reagent cuts down on the amount of waste generated in an experiment
by allowing the students to bypass the workup steps necessary for neutralizing
a reaction containing sulfuric acid.
Furthermore, this reagent is very safe to use, relative to a strong acid
such as sulfuric.
We are also
very conscientious about the solvents we incorporate into our experiments. Ethanol, water and mixtures of the two are
used as often as possible. However, we
have not entirely eliminated hazardous solvents from our curriculum for two
reasons. First, it is not always
practical. For example, there are no
suitable substitutes for methylene chloride as a solvent for the Friedel Crafts
reaction, an experiment the students generally perform. Secondly, it is important to teach students
how to work with and properly dispose of several classes of chemicals.
BSJ: How did you become interested in this field of study?
Dr. Pedersen: It was a natural progression. I have been
doing synthetic chemistry for over 20 years. I also happen to be concerned
about the environment and saw it as a challenging area to pursue. Coupled with
undergraduate laboratory development, which in itself is very challenging, I
just put the two together. I see a lot of college-age students being very
concerned about the environment. It
seemed like a perfect match of interests.
BSJ: How do you develop lab experiments for the
undergraduate chemistry courses?
Dr. Pedersen: There are a few different approaches. For
example, if I determine that there is an area in lecture that is not well
represented in the laboratory, then I will start exploring what types of experiments
would fit the bill. Another approach
is to read the current chemical literature.
I am always looking for new chemistry, whether it is a new twist on an
old reaction or an entirely new approach to a given problem. I also happen to find many interesting
reactions in the old chemical literature.
In either
case, the real challenge is incorporating these experiments into our
curriculum. What this entails is taking
an experiment that was developed in a research laboratory equipped with large
quantities of glassware and analytical equipment and then seeing if you can
adjust the experiment to fit into a three-hour lab period, with minimal
glassware and virtually no analytical equipment other than TLC (thin-layer
chromatography). Included in all this
are some "green" adjustments and substantial efforts to transform the
experiment into a puzzle.
BSJ: What do you enjoy about teaching organic chemistry?
Dr. Pedersen: The students! The diversity of our students?
backgrounds is incredible. I enjoy talking with students, whether it is after
class, in office hours or at a local grocery store. The other aspect of teaching organic chemistry that is thoroughly
enjoyable is when I have an opportunity to show the students that what they are
learning is relevant to everyday objects and life itself. I do this most often via my molecule of the
day, a time at the end of lecture where I digress for 5-10 minutes and discuss
the connection between a given molecule and its impact on some aspect of
society. It is always fun to take everyday things and say, hey, we just learned
about this last week in class, and it is in the newspaper today.
BSJ: Why do you feel it is important for students to know
about these examples and applications?
Dr. Pedersen: I would like them to realize that there is
more to organic chemistry than just taking tests and getting grades. I want students to leave feeling that they
have actually learned something useful.
Something that will empower them to make informed decisions about a
variety of topics, from politics to nutrition.
One of the
things I always do near the end of the semester is to go over a food ingredient
label from some type of packaged food.
I think the students are quite surprised at how many of the ingredients
they actually recognize after having taken a year of organic chemistry. Even more interesting is that after
discussing some of the chemistry of food additives, they can understand, via
chemical principles, what all of the other ingredients are and why they are
present.
BSJ: What type of research did you do as a graduate student
and postdoctoral scientist?
Dr. Pedersen: I did research in the field of organometallic
chemistry as a graduate student, and I worked in the area of organic/inorganic
synthesis as a postdoc. For my doctorate, I primarily synthesized and studied
organometallic complexes. As a postdoc, I started to apply my experiences in
inorganic synthesis to the synthesis of organic molecules using transition
metals as catalysts.
BSJ: How have your research interests changed over time
since your college years? Was the change due more to technological advances or
more from a shifting of personal interests?
Dr. Pedersen: As we discussed before, my emphasis in
research has shifted from the development of new synthetic methods, to the
development of laboratory curricula.
Although this is not often considered fundamental research, I believe
the efforts have paid off. The change
itself was based more on my increased interest in teaching rather than anything
having to do with technology.
BSJ: What were your most memorable experiences during your
undergraduate years at UCLA, and your years at MIT? What did you enjoy most?
What led you to go into the field of organic chemistry specifically?
Dr. Pedersen: I had
a lot of fun in college. I did not start off in chemistry and, in fact, didn?t
declare the chemistry major until my third year at UCLA. Therefore, I ended up staying five years.
Before deciding on chemistry as a major, I had declared myself a biology major,
which of course meant I had to take chemistry.
By the time I had taken my first biology course, I was really enjoying
chemistry, and Biology 1A was not nearly as interesting to me.
After
becoming a chemistry major, I was introduced to undergraduate research. Basically, the research group I joined,
known as the Kaesz group, after the research director, became my on-campus family. I had a great time and it was during those
two years that I decided I wanted to go to graduate school in chemistry. I chose to go to MIT because I thought it
was a perfect match for my interests and I felt it was time to live in a
different area of the country, having lived in Southern California all my life.
The
research group I joined at MIT was well known for working long hours; 16-hour
days were not uncommon. However, it wasn?t because we had a research director
with a whip. It was because we enjoyed
what we were doing. There was a real
buzz in the air of excitement when we were in the lab. We also knew how to play in our spare
time. We fielded a softball team and
participated in other intramural sports. I met my wife at MIT during graduate
school, and stayed two more years there as a postdoc, until we moved to Berkeley. I had a great time in graduate school and
the highlight of my stay at MIT was meeting my wife.
BSJ: How did you get involved in research during your fourth
and fifth undergraduate years?
Dr. Pedersen: A
teaching assistant in one of my organic chemistry laboratory courses
noticed that I was really enjoying what was going on in lab and asked if I was
interested in doing some undergraduate research. I met with his research director, and he was very encouraging.
Before I knew it, I was there doing research, and I had a great time.
BSJ: What influential role models have you had that sparked
your interest in science, organic chemistry or teaching?
Dr. Pedersen: My getting into chemistry was very roundabout.
There was no role model that sparked my interest in science. I was simply lucky enough to have had some
very good teachers early on in my studies that made the subject interesting
enough to take a second look. Those
teachers coupled with my research experience led me to graduate school.
While in
graduate school, my research advisor provided me with the perfect environment
to excel. He showed constant interest
in my work, but also gave me enough leeway to make some mistakes and
discoveries on my own. He was, and
still is, an exceptional person and mentor.
My postdoc advisor was the icing on the cake to my years of academic
studies. He was supportive and a real
joy to talk with, whether it be about science or fishing.
BSJ: Can you tell us
about your family?
Dr. Pedersen: My wife and I met playing softball. She was a
graduate student in another group and was trying to put together a team. She ended up in our research group one day
and a bunch of us signed up. One thing
led to another and two years later we were getting married in a small town
called Brookline. My son was born while
we were both still postdocs. We came out to Berkeley when he was four months
old. Three years later my daughter was born on Halloween evening. My son is now
fourteen and my daughter just turned 11.
My wife is a research professor in the department, and is director of
our analytical facilities.
BSJ: What do you
enjoy doing in your time away from school?
Dr. Pedersen: I enjoy spending time with my wife and
children. My kids and I play
basketball together on the basketball court we built. Now that my son is in high school, we try to go to as many of his
basketball games as possible. My
daughter has taken up swimming and we are now into the monthly competitive
swimming meet circuit. In the spring my
son and I coach my daughter?s basketball team, something I?ve been doing for
the past three years.
I also
enjoy gardening. My garden isn?t large but I enjoy working it. I focus mainly
on growing herbs. Interestingly enough, my interest in herbs stemmed from the
molecule of the day lectures I mentioned earlier. Those who have taken my course realize that a lot of the
molecules I talk about are derived from plants. I decided it would be fun to grow some of the plants I mentioned
in class, and before I knew it, I was growing all kinds of herbs. I am mainly interested in those that have
unique odors. There is something very pleasing about brushing up against a
plant and being enveloped by a particular fragrance.
I also
enjoy fishing. Although I don?t get out very often, it is
a real pleasure when I can find a day to sit in a boat, fishing with my
father. My daughter is also an avid
angler and she never passes up the opportunity to go fishing with her
grandfather and dad.
BSJ: What plans do you have for the future?
Dr. Pedersen: Actually I?m quite happy with what I?m doing
in terms of teaching and lab development. In the short term I?m always looking
for ways to make Chemistry 3 more interesting. Last fall, I had a Chemistry 3
Exposition where each laboratory section in the class was given a subject to
research. Of course, the research was
focused on the organic chemistry of that subject. We rented Pauley Ballroom for an afternoon and each group set up
a booth to present their results. All
of the groups had completely different presentations. I was really impressed with the student?s enthusiasm and artistic
abilities and learned a great deal more about the chemistry of the subjects
chosen. I have since used some of this
chemistry as material for my molecules of the day. I am planning on holding another expo in the near future.
Other plans
for the future include enjoying the company of my children as much as I can
while they are still at home. I am
always amazed at how fast they grow-up.
BSJ: How would you like to see your work applied to society?
Dr. Pedersen: I would like to see more people teach, or is
it preach, the green approach to chemistry at the undergraduate level. The hope is that chemists and non-chemists
alike will take this philosophy with them and apply it to their future
scientific endeavors.
I would
also like to think that my approach to teaching organic chemistry will
influence the way future politicians think about science, namely, I want them
to embrace it, not fear it. As
far-fetched, as this may seem, when you teach 500 students a semester over the
course of many years, the chances of having spoken your message to a future
lawmaker are pretty good. Idealistic
you say, but who knows. It is certainly
one reason of many for continuing to teach and promote science to our younger
generations.
BSJ: Switching over to focus on your comment about the
pharmaceutical industry, how do you see the field of chemistry contributing to
the $500 million Health Sciences Initiative that was recently approved by
Chancellor Berdahl?
Dr. Pedersen: Basically, the initiative could not have succeeded without involvement from
chemistry. Chemistry is fundamental to
biological processes, and a great deal of effort has recently been focused on
understanding biological systems at the molecular level. As a result, the field of bio-organic
chemistry has emerged as a major contributor to the biotechnology industry.
BSJ: It has been said that physics was the science of the
20th century and biology/ biotechnology will be the science of the 21st. Where
do you see the discipline of chemistry fitting into that picture? Do you see it
fading or emerging?
Dr. Pedersen: Chemistry is the science upon which all other
sciences can expand and grow. It will
never fade away but it is very good at changing colors.
BSJ: What kind of scientific breakthroughs do you most want
to educate the world about?
Dr. Pedersen: I would like to educate the world, or at least
the 500 students in Chem3B, about how drugs interact at the molecular level and
how it is that people go about discovering certain pharmaceuticals. I had a
molecule of the day not too long ago where I talked about the differences
between tamoxifen and raloxifene and why it now appears they have behaved
differently in many medical studies. The differences between the two are
subtle, yet the medical effects can be substantial. Presented in the appropriate manner, the chemistry was
understandable to Chemistry 3B students.
Issues that
affect health are very important and I?d like to spend more time on them. That
requires research on my own part since I have never specialized in this
field. However, learning about these
areas and then trying to convey it to students who have barely had a year of
chemistry is a worthwhile goal and for myself, a very rewarding and educational
experience.
BSJ: Which breakthroughs do you feel are most important for
the average person to know about and understand?
Dr. Pedersen: Those related to general health, nutrition and
the environment. It is important that
students are enabled with enough information to ask their doctors and
pharmacists important questions about their health. Furthermore, the "health" of our environment will
ultimately dictate the "health" of our world.
BSJ: What type of advice or words of wisdom would you give
to aspiring scientists?
Dr. Pedersen: Take the time to learn how science applies to
everyday objects and life. If you do
this, the process of learning never ends because every physical object you
encounter functions on some scientific principle. You may have to peel back the layers of complexity to get to a
simple explanation, but that can be where the real fun begins!
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