Synthesis and properties of polyacetylenes with salicylideneaniline groups

Abstract

AbstractAcetylenes containing salicylideneaniline groups—N‐salicylidene‐3‐ethynylaniline (1), N‐(3‐t‐butylsalicylidene)‐3‐ethynylaniline (2), and N‐(3‐t‐butylsalicylidene)‐4‐ethynylaniline (3)—polymerized smoothly and gave yellow to red polymers in excellent yields when a rhodium catalyst was employed. Polymers with alkyl substituents on the aromatic rings [poly(2) and poly(3)] were soluble in CHCl3, tetrahydrofuran, and so forth, whereas the polymer without alkyl substituents [poly(1)] was insoluble in any solvent. N‐(3‐t‐Butylsalicylidene)propargylamine did not provide any polymer. Thermogravimetric analyses of the resultant polymers exhibited good thermal stability (To, onset temperature of weight loss > 300 °C). The ultraviolet–visible spectra of the polymers showed absorption maxima and cutoff wavelengths around 360 and 520 nm, respectively. The polymers exhibited largely Stokes‐shifted fluorescence (emission wavelength ≃ 550 nm) upon photoexcitation at 350 nm, which resulted from the photoinduced intramolecular proton transfer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2458–2463, 2002