Supramolecular Materials from Liquid Crystalline Phthalocyanines

University Of Arizona, Tucson AZ

Investigators

Abstract

Prior NSF supported research has led to several effective methods to polymerize self-organized amphiphilic monomers in a variety of lyotropic mesophases including lamellar, bicontinuous cubic, and inverted hexagonal phases. These studies provide the background for the proposed research into the formation of supramolecular materials from highly ordered columnar assemblies of octasubstituted phthalocyanines (Pc). Strong pi-pi interactions betweeen ordered arrays of the prototype Pc 1, i.e. 2, 3, 9, 10, 16, 17, 23, 24-octakis-((2-benzyloxy)ethoxy) phthlocyaninato Cu(II), control the phase and surface behavior of the Pc. The well ordered discotic columnar unit cells of Pc's similar to 1 will be used to create one-dimensional rod-like polymers, as well as create free standing or surface bound self-assembled Pc aggregates of defined size on the nano scale by enhancing the self-assembly characteristics of octasubstituted Pc. The self-assembled Pc aggregates may be composed of a single Pc or alternating pairs of Pc, in the same sense as alternating copolymers. These goals will be pursued by the preparation and characterization of octasubstituted Pc that incorporate specific self-assembly moieties to facilitate the formation of columnar arrays of alternating pairs of Pc. In addition unsymmetrical Pc will be prepared that are composed of three subunits similar to Pc1 with the fourth having an attached random coil oligomer. The balance between the attractive N-N interactions and the repulsive coil-coil interactions is expected to control the aggregation of these disc-coil oligomers. The synthesis and molecular characterization studies on these new nanomaterials will be complemented by collaborative analytical studies. %%% Supramolecular materials can be created by the design of molecular entities that self-assemble and/or self-organize into non-covalently associated ensembles on the nano to micro scale. The organized nature of these materials offer several attractive features for applications in both biological and materials sciences, e.g. catalysis, separations, surface modification, therapeutics, diagnosis, signal transduction, among others.