Introduction - Specialized Research AI at MIT

Introduction

Jerrold Meinwald

JERROLD MEINWALD, a Fellow of
the American Academy since 1970,
is the Goldwin Smith Professor of
Chemistry Emeritus at Cornell Uni –
versity. His research has contrib –
uted to a wide range of chemical
and chemical biological subjects,
including organic photochemistry,
reaction mechanisms, the synthe-
sis of chiral inhalation anesthetics,
natural product chemistry, and
chemical ecology. His publications
include the edited volumes Chem –
ical Ecology: The Chemistry of Biotic
Interaction (with Thomas Eisner,
1995) and Science and the Educated
Amer ican: A Core Component of Lib-
eral Education (with John G. Hilde-
brand, 2010). He is Secretary of the
American Academy and Cochair of
the Academy’s Committee on Stud –
ies and Publications.

Why “From Atoms to the Stars”? In the Summer

2012 issue of Dædalus, entitled “Science in the 21st
Century,” May Berenbaum and I sought to provide
representative accounts of recent progress in the
natural sciences. But it turned out that two areas of
the physical sciences–astronomy and chemistry–
cried out for more extensive attention than we
were then able to provide. Consequently, Jeremiah
Ostriker and I recruited a group of outstanding as –
tronomers and chemists to write a set of essays to
complement this earlier issue. Each of the new es –
says in this volume discusses important scienti½c
developments in astronomy and chemistry in spe –
ci½c areas of study to which the authors themselves
have made major contributions.

Philosophers, alchemists, and subsequently chem –
ists have examined the properties and transforma-
tions of matter in all its diversity for over two mil-
lennia. The pace of progress of these studies (and,
in fact, in all areas of science) picked up markedly
toward the end of the eighteenth century, and has
been increasing rapidly ever since. It was not until
twenty years after the ½rst performance of Stravin-
sky’s The Rite of Spring (and, I was shocked to realize,
during my own lifetime!) that it became clear, with
James Chadwick’s discovery of the neutron in 1932,
that all ordinary matter is made up simply of protons,
neutrons, and electrons. While protons and neutrons
were at ½rst believed to be the fundamental parti-
cles making up atomic nuclei, they have since the
1960s been best understood as composite subatomic

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Intro –
duction

particles, each made up of three inseparable
quarks. Protons (which carry a single posi-
tive charge) consist of two up quarks and
one down quark. Neutrons (electrically neu –
tral) comprise one up quark and two down
quarks. Interestingly, this revolutionary
structural insight into the nature of mat-
ter has had no impact at all on our under-
standing of chemistry.

The simplest atom, hydrogen (H), which
is not only the most abundant form of or –
dinary matter in the observable universe
but also the most abundant atom in our
own bodies, consists of a single nu clear pro –
ton and a single planetary electron. The
addition of one or two neutrons to the pro-
ton yields the hydrogen isotopes deuterium
and tritium, respectively. The combination
of two nuclear protons and two neu trons,
along with two planetary electrons, pro-
duces an atom of helium (He). With the ex –
ception of tiny amounts of lithium (Li),
whose nucleus contains three protons,
these are the sole types of atom produced
as a consequence of the Big Bang some 13.8
billion years ago. From a chemist’s view-
point, there are some ex tremely important
differences between hydrogen and helium
atoms. Hydrogen atoms are able to bond
to many other types of atoms to form stable
molecules such as elemental hydrogen
O), ammonia (NH
2), water (H
(H
3), meth-
2
ane (CH
4), and literally millions of other
“organic” compounds (all of which also
contain carbon). Helium atoms, in con-
trast, prefer to re main alone.

It was not until the mid-nineteenth cen –
tury (1869) that Dmitri Mendeleev taught
us that all the known elements, when listed
according to increasing atomic number
(the number of protons in the nucleus),
could be arranged into a “periodic table.”
His table revealed that the fewer than one
hundred naturally occurring elements fall
into periodically recurring groups (such as
noble gases and halogens), a ½nding that
enabled him to predict (correctly) the ex –

istence of unknown “missing” elements
that remained for future research to dis-
cover. Our understanding of how, where,
and when all the elements with an atomic
number greater than two (quaintly re –
ferred to as “metals” within the astronom-
ical community) were produced is much
more recent and still somewhat incom-
plete. Anna Frebel’s account in this volume
of the origin of these elements following
the Big Bang is a fascinating story that is
much less well known (even among chem –
ists) than it deserves to be. Her essay
(among the astronomy contributions) pro –
vides an ideal introduction to the very ex –
istence of chemistry and of life itself.

Christopher Cummins responded to our

invitation to write an essay on inorganic
chemistry by examining the chemistry of a
single element: phosphorus (P). In his ex –
ploration of phosphorous, we learn that
py rophoric (spontaneously combustible)
ele mental white phosphorus consists of
discrete P
4 molecules in which each phos-
phorus atom occupies the vertex of a tet –
rahedron, the simplest of the ½ve Platonic
sol ids. (By a striking coincidence, Plato
tells us that Timaeus considered the “ele-
ment” ½re to be composed of tetrahedral
particles!)

Cummins’s research on how the synthe-
sis of phosphorus-containing compounds
might be greatly simpli½ed exempli½es
the oretical and experimental chemical
thin king at its best. From a consideration
of the complex genesis and low abundance
of phosphorus in the universe (where it is
relatively rare) and in living organisms
(where it occurs in concentrations much
higher than it does in our solar system), we
move on to accounts of its vital importance
in agriculture and industry.

Tracing the passage of phosphorus from
the soil into plants, then into animals, and
½nally into the sea illuminates some seri-
ously underappreciated ecological con-

Dædalus, the Journal of the American Academy of Arts & Sciences

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cerns. The sad tale of the rise and fall of
the chemically innovative Canadian re –
search project that aimed at improving
agricultural phosphorus use by creating a
breed of pig, the Enviropig, able to digest
plant-derived phosphorus compounds in
its diet better than any previously existing
breed of pig, brings this essay to a close. It
may come as a surprise that the study of a
single element reaches into such a wide
range of human concerns, spanning agri-
culture, industry, the health sciences, ecol –
ogy, and even the social sciences. Readers of
Cummins’s essay will be rewarded not on –
ly with insights into some beautiful sci ence,
but also with extensive material for chem –
istry-based cocktail party conversation.

The borders between the classical scien-

ti½c disciplines are rapidly disappearing,
but continuing in the more or less tradi-
tional ½elds of inorganic and physical chem-
istry, John Meurig Thomas has given us
an intriguing essay on chemical catalysis,
embedded in a wide-ranging examination
of the importance of unpredictability and
chance within and beyond chemistry. His
vision of the “chemist” leans in the direc-
tion of what used to be termed “natural
philosopher.” He provides a refreshing
view of the world of chemical research,
with an emphasis on the importance of
entirely unanticipated discoveries and un –
foreseen practical applications. His case
studies serve to remind us of the remark-
able value of curiosity-driven research.
There is an important message here for
society at large with respect to shaping the
most productive science policy.

The discipline of chemistry has quietly
undergone an absolutely remarkable trans –
formation (or perhaps expansion would be
a better term) over the last half-century.
This development has manifested itself in
part through the examination of biology as
a molecular science. With our increasing
understanding of the chemistry of pro teins,

nucleic acids, and the myriad “small mole-
cules” that serve as molecular messengers
throughout nature, dramatic and even un –
imaginable improvements in the practices
of medicine (including psychiatry) and ag –
riculture are certain to play a prominent
role in the twenty-½rst century. In another
direction, with the successful synthesis ½rst
of the simplest organic molecules (urea,
ethyl alcohol, vanillin) and then of many of
the much more complex structures (cho-
lesterol, vitamin B-12, insulin) far behind
us, can the construction of synthetic vi –
ruses and even living cells be far off?

Another major opportunity for research
that is occupying the attention of many
contemporary chemists is the develop-
ment of materials science, an area discussed
in Fred Wudl’s essay. As a result of many
advances in physics, we know vastly more
than we did only a few decades ago about
the way atomic and molecular interactions
influence the macroscopic properties of
all sorts of materials. We know why some
materials are brittle, flexible, good elec-
trical conductors, good electrical insula-
tors, magnets, or light emitters or ab –
sorbers. As the physics of all these phe-
nomena is better understood, it becomes
possible for chemists to design and pro-
duce new materials from which everything
from “improved” fabrics to computers,
airplanes, and televisions can be made.
Quite remarkably, the element carbon
plays a central role in the design of many
of the novel materials with desirable prop –
erties, such as “self-healing” plastic (vitri –
mers) or solar photovoltaic cells. Wudl’s
essay outlines how this area of chemistry
evolved and what we may expect from it
in the decades to come.

Chaitan Khosla has focused his essay on
the ½eld that has become known as chem-
ical biology. Perhaps influenced by the an –
cient Greek aphorism “know thyself,” he
places particular emphasis on the roles
that chemistry plays in understanding (as

Jerrold
Meinwald

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143 (4) Fall 2014

Intro –
duction

well as improving) the lives of Homo sapi-
ens. Chemistry lies at the heart of much
medical research, from the development
of noninvasive imaging techniques such
as mri and pet scans to the discovery of
new molecular targets that may serve as
the basis for the design of much-needed,
novel anti-infective agents to help battle
malaria, Lyme disease, sars, and many
other threats to human health. In some
areas, the chemistry and biology relevant
to health is already fairly well understood,
and “translation” from theory to applica-
tion can be expected to proceed smoothly.
In others, such as the chemical/biological
understanding of brain functioning or the
control of development, basic research re –
mains an essential precursor to human
ap plications. Khosla’s essay illuminates a
½eld the chemical basis of which is not
yet widely enough appreciated.

Chemistry is an experimental science.

Some of its complexity derives from the
fact that it deals typically with huge num-
bers of molecules at a time; after all, an
O
ounce of water contains about 1024 H
2
molecules, roughly equal to the estimated
number of stars in the observable universe.
Nevertheless, the enormous power of con –
temporary computers, combined with fun –
damental physical insights provided by the
development of quantum mechanics, has
resulted in the birth of computational
chemistry, which provides both explana-
tions and predictions of chem ical proper-
ties and behavior. K. N. Houk and Peng Liu
describe examples of the power of com –
putational chemistry in predicting the
prod ucts of chemical reactions, in under-
standing the course of newly discovered
catalytic reactions, and even in designing
synthetic enzymes cap able of catalyzing
reactions for which no natural enzymes
exist. Although the power of computation-
al chemistry is now apparent, the science
is still in its infancy.

The world of computational chemistry
is a far cry from the chemistry labs of our
youth, with their litmus paper, Bunsen
burners, and distilling flasks. The pungent
odors of bromine or nitrobenzene, the
beau ty of deep-purple potassium perman-
ganate crystals, the brilliance of burning
magnesium, the eerie blue glow of luminol
treated with hydrogen peroxide (experi-
ences that have attracted generations of
young students to chemistry in the past)
are absent from this new world. They are
replaced by the less sensual but neverthe-
less deeply satisfying insights that only the
computer can give! There can be no doubt
that much of the sort of chemical research
that is now being carried out in the con-
ventional laboratory with actual chemicals
will be done within the next few decades
faster, cheaper, and more safely by compu-
tational chemists sitting in their of½ces.

In summation, what we have here is a ½ve-

course chemical tasting menu. It would
have been possible to choose ½ve entirely
different aspects of chemistry that would
have given an equally appropriate account
of the rapid advance of this lively disci-
pline. In many menus, some of the courses
or wine-pairing descriptions use unfamil-
iar terminology. Understandably, we are in –
clined to avoid incomprehensible or un –
pronounceable items. Describing chem-
istry presents an analogous challenge; one
of the great problems in writing about sci –
ence is how to eliminate jargon. But this
dif ½culty can be readily taken care of these
days simply by googling the ob scure terms
(Wikipedia also offers highly informative
accounts of everything from the Platonic
solids, neutrons, the periodic table, and
phos phogypsum to the Enviropig and
pet scans). Whether chemistry always in –
trigued you, or whether it was your worst
subject in high school, I hope you will ½nd
yourself enjoying what our dedicated au –
thors have to say. Bon appétit!

Dædalus, the Journal of the American Academy of Arts & Sciences

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