Complementary C3-symmetric donor-acceptor components: cocrystal structure and control of mesophase stability.
The overlap of pi-complementary planar organic frameworks is used to direct the assembly of extended columns of alternating donor and acceptor units. The electron-rich partner, hexaalkoxytriphenylene, is a familiar mesogen, while the electron-accepting complement is mellitic triimide, a new C(3)-symmetric building block that may be readily alkylated at its periphery without compromising its electron-accepting ability. A cocrystal of examples of the two components demonstrates pi-facial overlap of the complementary aromatic surfaces. Preparation of a series of alkylated derivatives of each component allowed the study of an array of 1:1 stoichiometry mixtures. For the optimum donor-acceptor organized mesophases within this grid, temperature stability ranges of well over 100 degrees C are observed, some of which extend below room temperature. X-ray analysis confirms the formation of hexagonally packed, alternating, donor-acceptor columns within each of the observed mesophases. The dramatic effect on mesophase formation and stability engendered via donor-acceptor organization within discrete columns is discussed in terms of the interplay of forces leading to mesophase formation, and the potential to tune mesophase characteristics via manipulation of these factors.
Park
Lee Y
LY
Department of Chemistry, Williams College, Williamstown, MA 01267, USA. Lee.Y.Park@williams.edu
Hamilton
Darren G
DG
McGehee
Edward A
EA
McMenimen
Kathryn A
KA