INVESTIGATION OF THE SOLID STATE CRYSTAL STRUCTURES OF CONJUGATED RIGID-ROD COMPOUNDS: PRELIMINARY ATTEMPTS TO CORRELATE PACKING WITH LIQUID CRYSTALLINE PHASE BEHAVIOUR. A.J. Scott, W. Clegg, Department of Chemistry, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, UK;, C Dai, P. Nguyen, G. Lesley, F. Somera, M.P. Hirsch, N.J. Taylor, T.B. Marder, Department of Chemistry, University of Waterloo, Waterloo, Ontario, NL2 3G1, Canada; C. Viney, Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK; V.Chu, Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA.

Rigid-rod shaped molecules are well-known for their tendency to form liquid crystalline phases. In order to probe the effect of substituents with differing electronic properties on liquid crystalline phase behaviour, a series of conjugated symmetric and unsymmetric ([[pi]]-donor/ acceptor), rigid-rod compounds composed of alternating aryl and alkynyl groups have been prepared. The solid state single crystal structures of these bis(phenylethynyl)benzenes (BPEBs) and diphenyl acetylenes (tolans) have been determined with a view to understanding the relationship between packing in single crystals and thermotropic liquid crystalline phase behaviour.