POLYBENZOFULVENES: MASS SPECTROMETRY CHARACTERIZATION

Benzofulvene (BF) derivatives were discovered to undergo spontaneous polymerization in the apparent absence of catalysts and/or initiator to provide a series of polybenzofulvene (PBF) polymers. Polybenzofulvenes represent a new family of polymers showing peculiar features such as the prompt and quantitative formation by spontaneous thermoreversible polymerization and the tunable solubility both in organic and aqueous media combined with interesting optoelectronic features[1]. Our studies reveal that the spontaneous polymerization process involving benzofulvene derivatives appeared to be very sensitive to the presence of bulky substituents in the close proximity of the polymerization center, but not when these substituents were located far from it. Generally, Polybenzofulvenes were chracterized by NMR, Mass Spectrometry, DSC, TGA and WAXD. Often, their photophysical and the cytotoxicity features were also studied. The unzipping process occurs very fast at temperature higher than 120-140 °C and was investigated by 1H-NMR and Direct Pyrolysis Mass Spectrometry. MALDI-TOF MS analysis gives peculiar and important information on the end groups and chemical structure of the P(BF)s, and then on the reaction mechanisms occurring during their synthesis. Mostly, the PBF chains are terminated with hydrogen at both ends as noted in Scheme 1. However, in the case of the P(BF)s derivatives bearing bithiophene chromophores in position 6 of the BF moiety (R3 in Scheme 1) the MALDI-TOF mass spectra reveal also the presence of oligomers having the bithiophene groups, belonging to a BF unit, linked directly to the methylene carbon of the initial unsaturated carbon C1[2].