Alternating copolymerization of 9,9‐dihexyl‐2,7‐dibromofluorene (HFl), N‐hexyl‐2,7‐dibromocarbazole (2,7‐HCz) or N‐hexyl‐3,6‐dibromocarbazole (3,6‐HCz) with Si‐containing divinyl or diallyl compounds, divinyldimethylsilane, divinyldiphenylsilane, 1,3‐divinyltetramethyldisiloxane, 1,4‐bis(dimethylvinylsilyl)benznene, diallyldimethylsilane, or diallyldiphenylsilane has been investigated using Mizoroki‐Heck reaction with a Pd catalyst. The corresponding alternating copolymers were obtained in good yield. The alternating copolymers from HFl or 2,7‐HCz showed good solubility in typical organic solvents. On the other hand, the copolymer with 3,6‐HCz became insoluble due to the crosslinking. Photophysical properties of the resulting copolymers were investigated with UV–vis absorption and photoluminescence spectroscopy. All the copolymers showed absorption peak derived from π–π* transition at around 340 nm, which was blue shifted in comparison with that of the corresponding homopolymer. Whereas emission peaks of the copolymers of the cast film were red shifted in comparison with that of the homopolymers. Multiple broad absorption peaks, which would be derived from intramolecular charge transfer through σ–π moiety, were also detected in the range from 390 to 450 nm in the spectra of the copolymers containing Si‐vinylene unit. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4513–4521, 2008

Alternating copolymerization of 9,9‐bis(3,6,9‐trioxadecyl)‐2,7‐dibromofluorene (ODFl) or 9,9‐bis(3,6‐dioxaheptyl)‐2,7‐dibromofluorene with Si containing divinyl compounds, divinyldiphenylsilane (VPS), or divinyldimethylsilane (VMS) is investigated using the Mizoroki–Heck reaction with palladium(II) acetate. The corresponding alternating copolymer is obtained in the copolymerization of ODFl with VPS. The copolymerization of ODFl with VMS yields low molecular weight oligomers. Optical properties of the ODFl–VPS copolymer have been investigated with UV–vis absorption and photoluminescence (PL) spectroscopy. The ODFl–VPS copolymer shows absorption peaks due to π–π* transition and intramolecular charge transfer through σ–π moiety at around 330 and 360–400 nm, respectively. An emission peak is observed at 450 nm in the PL spectrum of the ODFl–VPS copolymer, and the PL quantum yield is 0.19. The PL spectroscopy of ODFl–VPS copolymer is investigated in the presence of Li+, Na+, and K+, and the intensity of emission peak is decreased by those metal cations, especially by Na+. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.

Alternating copolymerization of 9,9-dihexyl-2,7-dibromofluorene, N-hexyl-2,7-dibromocarbazole (HCz) with diethynyldimethylsilane, diethynyldiphenylsilane, has been investigated using Sonogashira coupling reaction. Photophysical properties of the resulting copolymers were investigated with UV-Vis absorption and photoluminescence spectroscopy. All the copolymers in chloroform solution showed absorption peaks at 270 -280 nm with shoulder peaks at around 380 nm derived from π-π * transition or intra-molecular charge transfer through σ-π moiety, respectively. The chloroform solutions of the copolymers showed broad emission peaks at 415 -425 nm. The emission wave lengths of the copolymers in the solid state (cast film) detected at 360 -385 nm were remarkably blue-shifted in comparison with those in the chloroform solutions. Hydrosilylation reaction of the copolymers with 1,4-bis(dimethylsilyl)benzene yielded networked copolymers soluble in chloroform, indicating formation of branching polymers. The chloroform solutions of the HCz-based networked copolymers showed bimodal emission derived from new highly energy states in the σ-π conjugation.