Cyclic and Telechelic Ladder Polymers derived from Tetrahydroxytetramethylspirobisindane and 1,4-Dicyanotetrafluorobenzene

Abstract

5,5,6,6-Tetrahydroxy-3,3,3,3-tetramethylspirobisindane was polycondensed with 1,4-dicyanotetrafluorobenzene in four different solvents at 70 °C. In dimethylformamide, N-methylpyrrolidone, and sulfolane exclusively, cyclic polymers were detectable by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry up to masses around 13,000 Da. In dimethyl sulfoxide, linear byproducts were also found. Higher temperatures caused degradation reactions catalyzed by potassium carbonate. Polycondensations performed with the addition of 4-tert-butyl catechol or 2,2-dihydroxy binaphthyl yielded linear telechelic oligomers. Equimolar mixtures of linear and cyclic ladder polymers were examined by MALDI-TOF mass spectra to determine how the end groups and the cyclic structure influenced the signal-to-noise ratio. The results suggested a preferential detection of the linear chains.