Synthesis, electrochemical and optical studies of new cyanopyridine based conjugated polymers as potential fluorescent materials

In this communication we describe the design and synthesis of four new conjugated polymers (P1-P4) carrying cyanopyridine in their backbone via Wittig condensation technique. Their structures were well established by FTIR, H-1 NMR, elemental analysis and gel permeation chromatographic techniques. They exhibited good thermal stability with the onset decomposition temperature around 300-350 degrees C in nitrogen atmosphere. Further, their electrochemical, linear and third-order non-linear optical properties have been investigated. The polymers showed low electrochemical band gaps in the range of 1.77 -1.99 eV and displayed very good fluorescence emission property in various polar solvents. The fluorescence quantum yields of polymers P1-P4 in tetrahydrofuran (THF) were found to be 35, 42, 38 and 34%, respectively. The effective two-photon absorption coefficients (beta) for the polymers were determined by Z-Scan technique and were found to be 1.34 x 10(-11), 1.24 x 10(-11), 3.04 x 10(-11) and 1.85 x 10(-11) m/W for polymers P1-P4, respectively. (C) 2011 Elsevier Ltd. All rights reserved.