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47401-SE
60 Years of Physical Organic Chemistry, at the ACS National Meeting, August 2007, Boston, MA
Steven Fleming, Brigham Young University
The symposium "60 Years of
Physical Organic Chemistry" was held at the 2007 Fall ACS Meeting in Boston on
August 22. There were 12 speakers
and attendance varied from 50 to 120 through the daylong event. There was also a banquet held the
evening of August 21 associated with the event. The titles of the presentations are listed below. The symposium was organized by David
Crumrine, Steve Fleming, and Laren Tolbert.
The
following two speakers were supported by this PRF-SE grant:
1) Hiizu Iwamura, Tokyo University
Title: Synthetic and supramolecular approaches
to carbene-based magnets.
Professor Iwamura's
abstract: Since the photochemical
production of bis(2,4,6-trichlorophenyl)carbene as a persistent triplet species
by Zimmerman, H. E. in 1964, diarylcarbenes have attracted a lot of scientific
interest as the building blocks for organic molecules having very high-spin
ground states. The work was highlighted by the construction of the nonacarbene
with a nonadecet (S = 9) ground state and therefore strong paramagnetic
properties. Having established that supramolecular approaches using high spin
organic ligands with magnetic metal ions are effective in constructing extended
and ordered spin systems, we pursued a potential of developing photoresponsive
magnetic materials. Photolysis of dilute-paramagnetic metal complexes carrying
di(4-pyridyl)diazomethane and its higher analogs as ligands gave the
corresponding polycarbenes in which the spins at carbene centers and magnetic
metal ions aligned as designed to form variously paramagnetic networks, spin
glasses, and single-molecule magnets. Some of the carbene centers survived at
230 K in the parent crystals.
2) Masahiro Irie, Rikkyo
University
Title: Photoresponsive diarylethene single
crystals
Professor Irie's abstract: Some diarylethene derivatives undergo
photochromism even in the single crystalline phase. The single crystalline
photochromism was proved by dichroism as well as in situ X-ray crystallographic
analysis. The X-ray crystallographic analysis revealed that the end to end
distance of the long molecular axis and the thickness of the molecules shrink
upon irradiation with UV light and expand upon visible irradiation. The
geometrical structural change in crystals induced the reversible change of the
surface morphology of the single crystals (1,2). Furthermore, the molecular
crystals based on diarylethene chromophores and with size ranging from 10 to
100 micrometers exibit rapid and reversible macroscopic changes in shape and
size induced by UV and visible light.
M. Irie et al., Science 291,
1769 (2001) 2. M. Morimoto, M. Irie, Chem. Commun. 3895 (2005)
The symposium recognized the
lifetime achievements of:
Howard Zimmerman, University
of Wisconsin
Professor Zimmeran's
abstract: This lecture contains
the beginning and the current research in what we term the "Z-Group". The
beginnings serve two purposes: (a) A historical one, and (b) Providing
background for the Current Research portion. The lecture deals with (i) stereochemistry, (ii)
photochemistry, (iii) solid-state chemistry, (iv) theoretical organic
chemistry. The beginnings include:
(1) the discovery of kinetic protonation stereochemistry, (2) the original
report of how photochemistry could be related to excited state structures, (3)
the first organic correlation diagram controlling reactivity. The recent research: (1) deals with the
controversy in zwitterionic rearrangements, (2) solid-state reactivity, (3) new
heterocyclic photochemistry and conical intersections involved, (4) the
structure and reactivity of allenic enolates.
Also participating in the
symposium were:
Laren Tolbert, Georgia
Institute of Technology
Title: Charge distribution in the ground and
excited states of resonance stabilized anions.
Marye Anne Fox, University of
California, San Diego
Title: Photochemistry at the nanoscale: Recent advances in photochemistry at
nanostructured surfaces.
Albert Padwa, Emory
University
Title: From photochemistry to alkaloids
Andrei Kutateladze,
University of Denver
Title: Detection and photoamplification of molecular recognition
events
David Schuster, New York
University
Title: Forty-seven years in organic
photochemistry
Richard Givens, University of
Kansas
Title: Photoremovable protecting groups:
Variations on the photo-Favorskii rearrangement – a mechanistic study
Josef Michl, University of
Colorado
Title: Covalently linked dimers of
1,3-diphenylisobenzofuran: Evidence for singlet fission
James Pincock, Dalhousie
University
Title: Effect of methoxy substituents on the
photoreactivity of arylmethyl substrates
Fred Lewis, Northwestern
University
Title: Photoinduced DNA electron transfer
revisited