Journal of the American Chemical Society, Vol.118, No.41, 9855-9866, 1996
Fluorophobic Effect Induces the Self-Assembly of Semifluorinated Tapered Monodendrons Containing Crown-Ethers into Supramolecular Columnar Dendrimers Which Exhibit a Homeotropic Hexagonal Columnar Liquid-Crystalline Phase
The rational design, synthesis, and characterization of the building blocks obtained by the esterification of the first generation of tapered monodendrons 3,4,5-tris(p-dodecan-1-yloxy)benzoic acid (12-AG) and 3,3,5-tris[p-(n-dodecan-1-yloxy)benzyloxy]benzoic acid (12-ABG) containing semifluorinated dodecyl groups [i.e., 12Fn-AG-15C5 (n = 0, 4, 6, 8), 12Fn-AG-B15C5, 12Fn-ABG-15C5, and 12Fn-ABG-B15C5 (n = 0 and 8) where n following the letter F represents the number of outer perfluorinated methylenic units of the dodecyl group] with 4’-hydroxymethyl(benzo-15-crown-5) (B15C5) and 1-hydroxymethyl(15-crown-5) (15C5) are described. All building blocks self-assemble into supramolecular cylindrical or rod-like dendrimers via ion-mediated complexation processes. These rod-like supermolecules form a thermotropic hexagonal columnar (Phi(h)) liquid crystalline (LC) phase. The fluorination of the dodecyl groups of these tapered building blocks enhances dramatically their self-assembly ability.
Keywords:ROD-LIKE MOIETIES;STARBURST CASCADE DENDRIMERS;CONVERGENT GROWTH APPROACH;SIDE-CHAIN POLYESTERS;DENDRITIC MACROMOLECULES;MOLECULAR-WEIGHT;HALF-DISK;BUILDING-BLOCKS;FUNCTIONAL POLYMERS;FLUOROCARBON CHAINS