Topochemical Polymerization of C70 Controlled by Monomer Crystal Packing
Alexander V. Soldatov,1*
Georg Roth,3
Alexander Dzyabchenko,4
Dan Johnels,5
Sergei Lebedkin,2
Christoph Meingast,1
Bertil Sundqvist,6
Miro Haluska,7
Hans Kuzmany7
Polymeric forms of C60 are now well known,
but numerous attempts to obtain C70 in a polymeric state
have yielded only dimers. Polymeric C70 has now been
synthesized by treatment of hexagonally packed C70 single
crystals under moderate hydrostatic pressure (2 gigapascals) at
elevated temperature (300°C), which confirms predictions from our
modeling of polymeric structures of C70. Single-crystal
x-ray diffraction shows that the molecules are bridged into polymeric
zigzag chains that extend along the c axis of the parent
structure. Solid-state nuclear magnetic resonance and Raman data
provide evidence for covalent chemical bonding between the
C70 cages.
1 Institut für Festkörperphysik,
2 Institut für Nanotechnologie,
Forschungszentrum Karlsruhe-Technik und Umwelt, Post Office Box 3640, D-76021 Karlsruhe, Germany.
3 Institut für
Kristallographie der Rheinisch-Westfälische Technische Hochschule
Aachen, Jägerstrasse 17-19, D-52056 Aachen, Germany.
4 Karpov Institute of Physical Chemistry, 103064 Moscow, Russia.
5 Department of Chemistry,
6 Department of Experimental Physics, Umeå
University, S-901 87 Umeå, Sweden.
7 Institut
für Materialphysik, Universität Wien, A-1090 Wien, Austria.
*
Present address: Department of Physics, Lyman Laboratory,
Harvard University, Cambridge, MA 02138, USA.
To whom correspondence should be addressed. E-mail:
soldatov{at}physics.harvard.edu
