Engineering Crystal Symmetry and Polar Order in Molecular Host Frameworks
K. Travis Holman,
Adam M. Pivovar,
Michael D. Ward*
A crystal design strategy is described that produces a
series of solid-state molecular host frameworks with prescribed lattice metrics and polar crystallographic symmetries. This represents a
significant advance in crystal engineering, which is typically limited
to manipulation of only gross structural features. The host frameworks,
constructed by connecting flexible hydrogen-bonded sheets with
banana-shaped pillars, sustain one-dimensional channels that are
occupied by guest molecules during crystallization. The polar host
frameworks enforce the alignment of these guests into polar arrays,
with properly chosen guests affording inclusion compounds that exhibit
second harmonic generation because of this alignment. This protocol
exemplifies a principal goal of modern organic solid-state chemistry:
the precise control of crystal symmetry and structure for the
attainment of a specific bulk property.
Department of Chemical Engineering and Materials Science,
University of Minnesota, 421 Washington Avenue Southeast, Minneapolis,
MN 55455, USA.
*
To whom correspondence should be addressed. E-mail:
wardx004{at}umn.edu
