Roald Hoffmann
(1937 - )
Roald Hoffmann was born in Zloczów, Poland (now Ukraine) and named in honor
of the Norwegian explorer, Roald Amundsen. His family immigrated to
the United States of America in 1949, where he attended Stuyvesant High
School, graduating in 1955. He received his Bachelor of Arts degree
at Columbia University (Columbia College) in 1958, and his Master of
Arts degree in 1960 and his Doctor of Philosophy degree (working under
the subsequent 1976 chemistry Nobel Prize winner William N. Lipscomb,
Jr.) in 1962, both from Harvard University.
He has investigated both organic and inorganic substances,
developing computational tools and methods such as the extended Hückel
method, which he proposed in 1963.
He also developed, with R. B. Woodward, rules for elucidating
reaction mechanisms.
He is also a writer of poetry published in two collections,
"The Metamict State" (1987) and "Gaps and Verges"
(1990), and of books explaining chemistry to the general public. Also,
he wrote a play called "O2 Oxygen" about the discovery of
Oxygen, but also about what it means to be a scientist and the importance
of process of discovery in science.
He received the Nobel
Prize in Chemistry in 1981. The following press release from the
Royal Swedish Academy of Sciences describes Hoffman and co-winner Kenichi
Fukui's work:
Chemical transformations of the microscopic (atomic)
structure of matter have been proceeding on Earth for billions of
years. These transformations, or reactions, play a part in the drama
of our planet's development. One of the prerequisites for life on
Earth is that chemical reactions should be governed by natural laws.
For thousands of years man has actively utilized chemical transformation
processes for mastering his environment - in preparing food and drink,
in fashioning tools and clothes, and in combatting disease, and so
on. This active utilization was initiated by chance discoveries made
in the daily round of practical living. The mass of empirical knowledge
grew so large in time that theoretical concepts had to be resorted
too, so that a meaningful overall view was possible. Theories thus
became necessary for the continued conscious and systematic utilization
of chemical reactions. The efforts of the Chemistry Prizewinners should
be seen as constituting one of the links in this chain of ongoing
development.
The Prizewinners' work aims at theoretically anticipating
the course of chemical reactions. It is based on quantum mechanics
(the theory whose starting point is that the smallest building blocks
of matter may be regarded both as particles and as waves), which attempts
to explain how atoms behave. The Chemistry Prizewinners' theories
developed via close interaction with the empirical findings of experimental
chemists. Hoffmann's first really powerful theoretical work carried
out in 1965 in collaboration with R.B. Woodward at the University
of Harvard. Woodward (died in 1979) was awarded the 1965 Nobel Prize
in Chemistry for contributions of a completely different kind - for
his outstanding achievements in building up complex organic molecules
experimentally. Fukui started his scientific work in experimental
chemistry.
More than 25 years ago, Fukui showed that certain
properties of the orbits of the most loosely bound electrons and of
the "most easily accessible" unoccupied electronic orbits
had unexpectedly great significance for the chemical reactivity of
molecules. He called these orbits "frontier orbitals". Fukui's
earlier frontier orbital theory attracted only little attention at
first. In the mid-1960s, Fukui and Hoffmann discovered - almost simultaneously
and independently of each other - that symmetry properties of frontier
orbitals could explain certain reaction courses that had previously
been difficult to understand. This gave rise to unusually intensive
research activity - both theoretical and practical - in many parts
of the world, Fukui and other researchers developed the frontier orbital
theory into a highly powerful tool for understanding the reactivity
of molecules. Hoffmann and co-workers elaborated the observations
he had made together with Woodward. These observations are collectively
termed the theory of conservation of orbital symmetry in chemical
reactions. Orbital interaction and symmetry relations between molecules
or parts of molecules are fundamental concepts in Fukui's and Hoffmann's
theories.
A characteristic feature of Fukui's and Hoffmann's
method of attacking difficult and complicated problems is that they
succeeded in making generalizations through simplifications. In this
lies the key to the strength of their theories. The theoretical models
that Fukui and Hoffmann introduced have been in many branches of chemistry
since the 1970s. Their method of conceiving of the course of chemical
reactions is utilized nowadays, for example, by chemists studying
life processes and by chemists making new drugs.
Good theoretical models provide guidance for experimental
researchers and save them time. Fukui's and Hoffmann's theories are
milestones in the development of our understanding of the course of
chemical reactions. This development has, however, by no means been
brought to a halt by the prizewinning work. This work has provided
inspiration for new lines of development. Fukui and Hoffmann are among
the most active researchers in these areas today.
He currently teaches at Cornell University in Ithaca,
New York.
Sources: Wikipedia;
Nobel
Prize.org |