Living cyclopolymerization reactions have made it possible to synthesize soluble, conjugated polymers. Characterizing the electronic properties of these compounds offers the potential to bridge the gap between short, linear polyenes, such as carotenes, and larger conjugated polymers of technological interest. In this study, we describe matrix assisted laser desorption/ionization (MALDI) sample preparation techniques for the analysis of polyenes that can be used to generate ions for analysis by Fourier transform mass spectrometry (FTMS). These methods have been applied to two types of polyenes. The first are oligomers fractionated from low molecular weight synthetic mixtures of poly(DEDPM) polymers, produced by the living cyclopolymerization of diethyldipropargylmalonate (Christensen, R.L. et al., J. Phys. Chem. A., 2004, 108, 8229), and provided by R. R. Schrock (Department of Chemistry, MIT). The second are mixtures of dimethylpolyenes (Christensen, R.L. et al., Arch. Biochem. Biophys., 2004, 420, 30). We report on ions generated upon cationization with alkali metal, silver, and copper ions. We show that radical cations can be produced for both types of polyenes, and that poly(DEDPM) radical cations fragment under the longer time-frame associated with MALDI-FTMS detection. The ability to produce gas-phase radical cations of novel polyenes for analysis by FTMS offers the potential to apply gas-phase chemical reactions to characterize electronic properties.
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