Main chain 1,1′‐ferrocene‐containing polyelectrolytes exhibiting thermotropic liquid‐crystalline and fluorescent properties

Abstract

AbstractA series of 1,1′‐ferrocene‐containing polyelectrolytes (3, 4) were prepared when 1,1′‐bis(N,N‐dimethylaminomethyl)ferrocene (1a) or 1, 1′‐bis{[1‐(2‐methyl)imidazol‐1‐yl]methyl}ferrocene (1b) was quaternized with 1,4‐dibromobutane or α, α′‐dibromo‐p‐xylene. The counterion was bromide or bis(trifluoromethanesulfonyl)‐amide formed after metathesis with the lithium salt. Their chemical structures were determined by IR and NMR spectra. Molecular weights in the range of ∼5400 (4a)– ∼14,700 (4c) for number‐average molecular weights (Mn) over narrow molecular weight distributions were determined for polymers 4 by gel permeation chromatography. Thermal properties of these materials were obtained by differential scanning calorimetry and thermogravimetric analysis that showed the polymers had thermal stabilities ranging between 172 and 330 °C. Liquid‐crystalline behavior was investigated on a hot stage polarizing optical microscope. Polymers 3a, 4b, and 4d formed either a high‐order or a low‐order smectic phase above their melting or fusion temperatures, and exhibited smectic‐to‐isotropic transitions. The ranges of the liquid‐crystalline phases for these materials were 22, 46, and >55 °C. Compounds 3b, 4a, and 4c are crystalline before melting or decomposing. All of the polymers exhibited absorption bands at ∼430 nm. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 974–983, 2005