Regioselective Synthesis of Tetraphenyl-1,3-butadienes with Aggregation-Induced Emission

In the presence of substoichiometric amounts of Co₂(CO)₈, internal bisarylalkynes undergo reductive dimerization with good to excellent yields. The Co₂(CO)₈-induced reactions described are experimentally quite simple and provide a very useful synthetic procedure for the synthesis of tetraphenylbutadienes which exhibit aggregation-induced emission enhancement, i.e., weak emission in good solvents but strong fluorescence in solvents that lead toward formation of aggregates or in the solid state

Facile Catch and Release of Fullerenes Using a Photoresponsive Molecular Tube

A novel M₂L₂ molecular tube capable of binding fullerene C₆₀ was synthesized from bispyridine ligands with embedded anthracene panels and Ag­(I) hinges. Unlike previous molecular cages and capsules, this open-ended tubular host can accommodate a single molecule of various C₆₀ derivatives with large substituents. The fullerene guest can then be released by using the ideal, noninvasive external stimulus, light

Facile Syntheses of Dioxythiophene-Based Conjugated Polymers by Direct C–H Arylation

Various substituted dioxythiophenes bearing 3,4-propylenedioxythiophenes (ProDOT) and 3,4-ethylenedioxythiophene (EDOT) moieties successfully undergo Pd-catalyzed direct C–H arylation to yield π-conjugated polymers. The effects of palladium catalysts, phosphine ligands or additives, and functional groups on this facile polycondensation approach are investigated. Polymers from alkoxy-substituted ProDOT are synthesized with reasonable molecular weight (<i>M</i>_n = 6100–9600) and low PDI (1.3–1.9). Four substituted EDOT with alkoxy or protected functional groups also undergo direct C–H arylation polycondensation to yield corresponding polymers. The obtained polydioxythiophenes exhibit UV–vis absorptions ranging from 480 to 590 nm, and these conjugated polymers are electroactive and reversibly switched between the oxidized and neutral states upon applying potentials

Converting Nonliquid Crystals into Liquid Crystals by <i>N</i>‑Methylation in the Central Linker of Triazine-Based Dendrimers

Two triazine-based dendrimers were successfully prepared in 60–75% yields. These newly prepared dendrimers <b>2a</b> and <b>2b</b> containing the −NMe­(CH₂)₂NMe– and the −NMe­(CH₂)₄NMe– linkers between two G₃ dendrons, respectively, exhibit columnar phases during the thermal process. However, the corresponding dendrimers <b>1a</b> and <b>1b</b> containing the −NH­(CH₂)₂NH– and the −NH­(CH₂)₄NH– linkers between two G₃ dendrons, respectively, do not show any LC phases on thermal treatment. Computational investigations on molecular conformations reveal that <i>N</i>-methylation of the dendritic central linker leads dendrimers to possess more isomeric conformations and thus successfully converts non-LC dendrimers (<b>1a</b> and <b>1b</b>) into LC dendrimers (<b>2a</b> and <b>2b</b>)