Thermal Solid State Polymerization ofp-Ethynylbenzoic Acid

Abstract

While p-ethynylbenzoic acid (EBA) has been suggested to be reactive in the solid state, the structure-reactivity relationships and the nature of the product(s) have remained unknown. Crystallized from toluene, EBA is a monoclinic crystal, space group P2 1/n, a ) 3.8684( 4), b ) 6.2329(4), c ) 30.190(3) Å; β ) 90.281(8)°; V ) 727.90 Å 3 . The crystal structure contains linear chains and short intermolecular contacts between acetylene moieties, which provide a structural basis for initiation of topochemical reactivity. Heating of EBA leads to an amorphous poly(phenylacetylene) (PPA) derivative. The absorption and emission spectral characteristics of the polymer are discussed. Analogous to PPA, a subsequent thermal process leads to a cyclic trimer. Differential scanning calorimetry of EBA exhibits at least four exothermic processes, and these are discussed in terms of the polymerization and subsequent processes that ultimately lead to the cyclotrimer.

Metal-Free on-Surface Photochemical Homocoupling of Terminal Alkynes

“…Crystalline PEBA reveals thermal and UV-induced reactivity. In the solid state, the photopolymerization reaction is topochemically promoted by the proximity of adjacent molecules within the crystal lattice . We therefore assumed that by taking advantage of the collinear displacement of neighboring alkynes on the HOPG surface, a topochemical homocoupling could be promoted photochemically.…”

Post-polymerization of preorganized assemblies for creating shape-controlled functional materials

“…However, Foxmann et al reported the crystalline-state controlled polymerization of a substituted phenylacetylene with high reactivity. 94 In the crystalline state, the molecular packing of the acetylene groups is in parallel arrangement, and the orientation is suitable for the resultant poly(acetylene) structures. However, the distance between the monomers is longer than that of the expected repeating distances.…”

Synthesis of brush-shaped polymers consisting of a poly(phenylacetylene) backbone and pendant poly(vinyl ether)s via selective reaction of 2-Vinyloxyethyl 4-Ethynylbenzoate

“…1‐(3‐Dimethylaminopropyl)−3‐ethylcarbodiimide hydrochloride (TCI, 98%), 4‐dimethylaminopyridine (DMAP; TCI, 98%), TFA (Wako, 98%), ethylaluminum dichloride (EtAlCl 2 ; Wako, 1.0 M in n ‐hexane), and 2‐hydoxyethyl vinyl ether (Maruzen Petrochemical, 99.9%) were used as received. p ‐Ethynylbenzoic acid was prepared according to a literature with some modifications. Isobutyl vinyl ether (IBVE; Aldrich, 99%) was dried overnight over KOH pellets, and distilled twice over CaH 2 .…”