MOLECULAR RECOGNITION DIRECTED SELF-ASSEMBLY OF SUPRAMOLECULAR LIQUID-CRYSTALS

The first part of this paper discusses the molecular design of selecte d examples of structural units containing taper shaped exo-receptors a nd various crown ether, oligooxyethylenic, and H-bonding based endo-re ceptors, which self-assemble into cylindrical channel-like architectur es via principles resembling those of tobacco mosaic virus (TMV). The ability of these structural units to self-assemble via a delicate comb ination of exo- and endo-recognition processes will be presented. A co mparison between various supramolecular (generated via H-bonding, ioni c, and electrostatic interactions) and molecular ''polymer backbones'' will be made. The formation of columnar hexagonal (Phi(h)), nematic a nd re-entrant isotropic phases by selected self-assembled systems will be discussed. The present limitations concerning the ability to engin eer the structural parameters of these supramolecular channel-like arc hitectures and some possible novel material functions derived from the m will be briefly mentioned. The second part of this paper discusses t he molecular design of a novel class of macrocyclics which self-assemb le via intramolecular recognition processes into supramolecular ''rod- like'' collapsed macrocyclics which display thermotropic liquid crysta lline mesophases. It will be demonstrated that these macrocyclics have a higher ability to form liquid crystalline phases than the correspon ding linear compounds which have identical or even higher degrees of p olymerization. Therefore, they represent the ideal molecular architect ures which generate nematic and smectic phases. The third part present s the concept and the synthesis of willow-like thermotropic dendrimers .