ORGN 68 |
| Polar molecules have a natural tendency to crystallize in such a way as to compensate dipole moments. This is a consequence of the simple facts that collinear dipoles prefer parallel alignment and coplanar dipoles prefer to be antiparallel. While many crystals have been realized in which the dipole cancellation is not complete, there are only a few examples with a significant dipole parallel alignment and none of those cases has led to repetitions or generalization. Since polar order is central to a variety of solid state properties, it has been our aim to develop a rational design for crystals of molecular organic materials with very high dipole-parallel alignment. Our approach involves the use of arene-arene interactions as lateral synthons to overcome the intrinsic dipole-dipole repulsions with quadrupole-quadrupole interactions. Halogen bonding provides for an important interlayer interaction and we have been able to employ halogen bonding to achieve near-perfect and perfect dipole-parallel alignment in crystals of the azines X-(C6H4)n-CMe=N-N=CMe-C6H4-Y (n=1,2; X=MeO; Y=Hal). |
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Materials, Devices, and Switches
1:00 PM-5:00 PM, Sunday, 13 March 2005 Convention Center -- Room 9, Oral
Division of Organic Chemistry |