Syntheses and properties of liquid crystalline N-substituted pyrroles and their polymers

Abstract

Three liquid crystalline N‐substituted pyrroles were synthesized from 6‐(1‐pyrrolyl)hexanol with phenolic derivatives having a mesogenic core of cyclohexylbenzene or biphenyl by Mitsunobu reaction. These pyrroles had two anodic peaks at 1.4 and 1.8 V (vs. SCE). The former was due to an oxidation of the pyrrole moiety and the latter was due to an oxidation of the mesogenic moiety. These pyrrole monomers were polymerized by electrochemical and chemical methods. The potentiostatic method and the chemical method using FeCl3 gave a soluble and fusible polymer, respectively. A polymer having a mesogenic core of cyclohexyl benzene obtained by the chemical method and a polymer having a mesogenic core of biphenylketone obtained by the potentiostatic method had a liquid‐crystalline phase. The phase was identified as smectic A by polarizing microscopy and XRD analysis. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2691–2698, 1998

Pyrrole derivatives for electrochemical coating of metallic medical devices

“…The resulting product is N-substituted pyrrole. 11 N-(2-carboxyethyl)pyrrole has been used to covalently bind enzymes to modify biosensor coatings. [12][13][14] For the purpose of preparing a series of pyrrole-based coatings with different properties, different N-substituted pyrrole monomers based on esterification or amidation of pyrrole propanoic acid (PPA), of Structure 1 where R represents methyl, ethyl, butyl, cyclohexyl, octyl, decyl, oleyl, and different lengths of poly (ethylene glycol)s (PEGs), were synthesized.…”

Pyrrole and polypyrrole-based liquid crystals containing azobenzene mesogenic groups

“…As part of this research effort, and in the continuing search for conducting liquid crystal polymers, much interest has been directed at thiophene and particularly at pyrrole-based systems. [2][3][4][5][6][7][8][9][10][11][12][13] In our studies focussed on pyrrole systems we have sought to investigate the influence of molecular structure on the thermotropic behaviour of the monomer species and to channel this understanding into the design and fabrication of liquid crystal polymer materials. Our research has centred on the attachment, via an alkyl chain, of a mesogenic group to the N-site of the pyrrole ring to yield mesogenic monomers and the subsequent polymerisation of these to give side group liquid crystal polymers based on a conducting pyrrole backbone.…”

“…Despite the growing number of studies on pyrrole-based liquid crystals, [2][3][4][5][6][7][8][9][10][11][12][13] there is no clear understanding of how molecular structure effects the mesogenic behaviour in this class of materials which are very different in nature to conventional low molar mass liquid crystals. In this respect we have undertaken a systematic study of monomeric molecular species.…”

Photoluminescence of a soluble polypyrrole based on N-vinylpyrrole

“…However, the band at 490 nm was believed to be due to a slight residual doping [27]. The p-p n transition of the polymer occurred at a significantly shorter wavelength than those of other substituted pyrrole polymers [24][25][26][27][28][29] and polypyrroles [15,22,23]. This lower value for the polymer was due to a short conjugated length related to the lower molecular weight.…”