Approaches to conjugated polymers via solid state polymerization

Abstract

Topochemical solid state polymerization is a method of obtaining fully crystalline macromolecules. Herein, approaches to conjugated polymers via new solid state polymerizations and the properties of materials, especially polydiacetylenes(PDA), obtained via solid state polymerization are discussed. Our attempts to polymerize cyanoalkynes and to define the thermal reaction product of a dicyanodiazepine are presented. Certain PDA exhibit absorption, likely charge‐transfer, at energies below the exciton. Nanocrystals of PDA‐DCH react with liquid bromine to give the mixed polyacetylene PDA‐DCHBr6 whose visible spectrum exhibits structure not observed in spectra of bulk crystals of PDA‐DCHBr6. The thermochromic PDA of the dialkylurethanes of 5,7‐dodecadiyn‐1,12‐diol were studied by variable temperature solid state 13C nmr. The upfield shift of the acetylene carbons as the temperature is raised above that of the thermochromic phase transition indicates the role of mechanical strains in achieving thermochromism.

Thermochromic Polydiacetylene Micro- and Nanocrystals: An Unusual Size Effect in Electronic Spectra

“…4 In earlier work, we have reproduced this spectral behavior and also prepared an electrostatic assembled film of PDA-DCH nanocrystals and poly(diallyldimethylammonium chloride). 5 These films were exposed to liquid bromine under conditions 6 that convert PDA-DCH to a mixed polyacetylene structure. These brominated films allowed observation of the visible spectrum of brominated PDA-DCH 5,6 with maxima at 540 and 479 nm.…”

Thermally Annealed Solid State Polymerization of 2,3-Dicyano-5,7-Dimethyl-6H-1,4-Diazepine: An NMR Study

“…Based on the NMR spectra, Scheme 1 suggests a plausible structure of polymer F. The IR and NMR data indicate that the polymerization involves only one of the two cyano groups, which is justified based on resonance structures of the monomer [4]. Unlike the monomer structure, the structure of the polymer consists of two chemically distinct methyl groups, secondary and tertiary amine groups (NR 2 H, NR 3 ), and alkene ( = CH) chemical moieties.…”

“…Here we present an unusual, novel example of a solid state polymerization. Crystalline monomer 2,3-dicyano-5,7-dimethyl-6H-1,4-diazepine (A) undergoes a solid state polymerization via thermal annealing yielding a conjugated polymer [3,4]. In this report, we discuss the idea of tautomerization of A as an integral aspect of the solid state polymerization process.…”

Synthesis of poly(p‐methoxyphenylacetylene) with the vanadium acetylacetonate‐aluminum triethyl Ziegler–Natta catalyst system: Cyclotrimers/polymer ratio analysis

“…The introduction of functional substituents into polyacetylene causes important changes in the polymer, such as solubility, melting, chemical, optical, electrical, and other properties. Substituted acetylenes were polymerized with a wide range of catalysts and conditions 20–32. Arylacetylenes were polymerized with Ziegler–Natta catalyst yielding often the cyclotrimer mixture and the polymer with low molecular mass.…”