Alkynyl-substituted phenyldithiafulvenes have been found to act as versatile building blocks for the construction of π-conjugated molecular rods, shape-persistent macrocycles (SPMs), and conducting polymers. Through Cu(I)-catalyzed alkynyl homocoupling, a series of linear-shaped π-extended tetrathiafulvalene analogues (exTTFs) carrying conjugated oligoynes (ranging from diyne to hexayne) as the central π-bridge were readily prepared. The solid-state properties and reactivities of diyne- and tetrayne-centered exTTFs were characterized by X-ray crystallography and differential scanning calorimetry (DSC), while the electronic properties of the oligoyne-exTTFs were elucidated by UV-vis absorption spectroscopy and density functional theory (DFT) calculations. Cyclic voltammetric analysis showed that the terminal phenyldithiafulvene groups of the oligyne-exTTFs could undergo oxidative coupling to form tetrathiafulvalene vinylogue (TTFV)-linked polymer wires. Through a different synthetic route involving oxidative dimerization and Pd/Cu-catalyzed alkynyl homocoupling, the acetylenic phenyldithiafulvene precursors led to shape-persistent macrocycles where the formation of trimeric macrocycles was particularly favored due to the small ring strain incurred. Finally, spectroelectrochemical studies on these oligoyne and TTF hybrid materials disclosed electrochromic and molecular redox-controlled switching properties applicable to molecular electronic and optoelectronic devices.

Although tetrathiafulvalene (TTF) and its derivatives have been extensively studied as important organic electronic materials over the past half century, tetrathiafulvalene vinyl-ogues (TTFVs) still remain a relatively underdeveloped branch in the family of TTF derivatives. Our recent work has investigated the synthesis and characterization of a class of diphenyl-substituted TTFVs carrying alkynyl functionality. The unique conformational and redox properties of such TTFV derivatives along with the versatile chemistry enabled by acetylenic groups (e.g., metal-catalyzed coupling and click reactions) have led us to a variety of functional molecular architectures ranging from oligoynes, polymers, and molecular tweezers, to macrocycles. Property studies of these new TTFV-based molecular materials point to appealing applications in molecular electronics and optoelectronics.

An acetylenic phenyldithiafulvene was developed as a versatile synthon for diverse TTFV-based macromolecular scaffolds. Through different coupling reaction sequences, shape-persistent macrocycles and linear TTFV-embedded polymers have been obtained and thereafter characterized by spectroscopic and voltammetric analyses. The TTFV polymer thin films generated via electropolymerization of a dithiafulvenyl-end-capped diyne monomer showed promising prospects in electrochromic and redox switchable molecular devices.

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The synthesis of carboxylated derivatives of poly(isobutylene-co-isoprene) (isobutylene-isoprene rubber, IIR) with substitution levels ranging from 1-4 mol% and different spacer lengths was accomplished by azide-alkyne Huisgen cycloaddition. Azido-functionalized IIR was first prepared by reacting brominated IIR to full conversion with sodium azide in a tetrahydrofuran/N,Ndimethylacetamide 90:10 mixture. The click reaction of the azido-functionalized IIR with acetylenic acids, using the copper(I) bromide/N,N,N′,N″,N″-pentamethyldiethylenetriamine catalyst system in tetrahydrofuran, gave the carboxylated IIRs. The products were characterized by 1 H NMR and FT-IR spectroscopy, and their molecular weight was determined by size exclusion chromatography analysis. The conversion to carboxylated groups reached up to 100%, as determined by NMR spectroscopy, but was highly dependent on the type of solvent and the amounts of catalyst and reactants used in the procedures.

Supramolecular interactions between a series of functionalized phenylene based pi-conjugated polymers and two types of as-produced single-walled carbon nanotube (SWNT) samples, namely HiPCO-NTs and CoMoCAT-NTs, were investigated by means of UV-Vis-NIR, Raman spectroscopy, and atomic force microscopic (AFM) analysis. In a non-polar organic solvent (chloroform), the effectiveness of these polymers in selectively dispersing different SWNT components according to electronic type, diameter, and chiral angle was examined and evaluated.

Triazole-Linked Dendro[60]fullerenes: Modular Synthesis via a "Click" Reaction and Acidity-Dependent Self-Assembly on the Surface. -(MAHMUD, I. M.; ZHOU, N.; WANG, L.; ZHAO*, Y.; Tetrahedron 64 (2008) 50, 11420-11432; Dep. Chem., Memorial Univ., St. John's, Newfoundland A1B 3X7, Can.; Eng.) -Lindner 11-226

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