[structure: see text] A convenient approach to a series of star-shaped pi-conjugated organic materials with oligofluorenes (OF) as the branches and a benzene ring as the core has been developed. The optical properties of these materials are liable to be tuned by introduction of more fluorene rings. The investigation of the structure-property relationship of these materials has indicated differences between star-shaped oligofluorenes and linear oligofluorenes, as well as polyfluorenes.

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Four polyfluorene derivatives with chiral center in the backbone or at the side chain, PLPheF (P1), PLPhGlyF (P2), PDPheF (P3), and PSPF (P4), have been designed and synthesized through the Pdcatalyzed Suzuki polymerization. The structures of these polymers are characterized by 1 H and 13 C NMR, UVvis, photoluminescence (PL), and CD spectroscopic methods as well as elemental analysis. These four polymers exhibit the linearly polarized photoluminescence in dilute solutions. The investigation of the absorption and emission behaviors indicates that the aggregates and/or the excited states excimers might be formed in THF solution at higher concentrations. We also observe the emission dichroic ratio R PL of these polymers in films is increased in comparison with that in solutions. After film annealing, polymers P1, P2, and P3 also show obvious linearly polarized photoluminescence at 500-650 nm. Moreover, the films of polymer P4 exhibit good thermal spectral stability after annealing in comparison with other three polymers P1, P2, and P3. We also report the circular dichroism (CD) spectroscopic properties of these four polymers in THF solutions.

A simple method is presented for calculation of the double-bond position in linear tetradecenols based on mass spectral data of dimethyl disulfide derivatives. In this approach, the m/z ratios of the molecular ion and of one (or both) of the two most abundant fragment ions were utilized to calculate the double-bond position, without the requirement to identify both fragment ions resulting from carbon-carbon cleavage across what was originally the double bond. The approach was tested with mass spectra of dimethyl disulfide derivatives of 12 isomeric tetradecenols, and the double-bond position in each isomer was successfully identified by this method. The method was shown to work also for the corresponding acetates.