| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 569.96 KB | Adobe PDF | |||
| 203.98 KB | Adobe PDF |
Advisor(s)
Abstract(s)
New highly fluorescent calix[4]arene-containing phenylene-alt-ethynylene-3,6- and 2,7-carbazolylene polymers (CALIX-PPE-CBZs) have been synthesized for the first time and their photophysical properties evaluated. Both polymers were obtained in good isolated yields (70-84%), having M-w ranging from 7660-26,700 g mol(-1). It was found that the diethynyl substitution (3,6- or 2,7-) pattern on the carbazole monomers markedly influences the degree of polymerization. The amorphous yellow polymers are freely soluble in several nonprotic organic solvents and have excellent film forming abilities. TG/DSC analysis evidences similar thermal behaviors for both polymers despite their quite different molecular weight distributions and main-chain connectivities (T-g, in the range 83-95 degrees C and decomposition onsets around 270 degrees C).
The different conjugation lengths attained by the two polymers dictates much of their photophysical properties. Thus, whereas the fully conjugated CALIX-PPE-2,7-CBZ has its emission maximum at 430 nm (E-g = 2.84 eV; Phi(F) = 0.62, CHCl3), the 3,6-linked counterpart (CALIX-PPE-3,6-CBZ) fluoresces at 403 nm with a significant lower quantum yield (E-g = 3.06 eV; Phi(F) = 0.31, CHCl3). The optical properties of both polymers are predominantly governed by the intrachain electronic properties of the conjugated backbones owing to the presence of calix[4]arenes along the polymer chain which disfavor significant interchain interactions, either in fluid- or solid-state.
Description
Keywords
Calixarene Carbazole Arylene ethynylene Polymer Fluorescence Fluorescence Containing conjugated Optical-properties Sensors Films Chemosensors Switches State
Citation
BARATA, P. D.; COSTA, A. I.; PRATA, J. V. – Calix[4]Arene-Carbazole-Containing Polymers: Synthesis and properties. Reactive & Functional Polymers. ISSN: 1381-5148. Vol. 72, nr. 9 (2012), pp. 627-634
Publisher
Elsevier Science BV