New fluorinated arylene vinylene ether (FAVE) polymers were prepared by a facile, metal-free condensation polymerization of fluorene, phenylenevinylene, dithiophene, or thiadiazole chromophore-containing bisphenols with bis(trifluorovinyloxy)biphenyl. The addition of chromophores encapsulated into the polymers were prepared in good yields and characterized by 1 H and 19 F NMR and GPC. Thermal analysis by differential scanning calorimetry (DSC) confirmed the polymers are entirely amorphous and are easy to solution process, producing optically transparent, flexible films. Thermal gravimetric analysis (TGA) showed they possess high thermal stability with decomposition temperatures of 340-387°C and 308-443°C in nitrogen and air, respectively. Chromophore inclusion was confirmed by ultraviolet-visible (UV-vis) spectroscopy, which demonstrated tailorable photoluminescence (PL) in both the solution and the solid state by selective substitution of the chromophore. Polymer thin film PL studies revealed notable red-shifts compared with polymer solutions presumably attributable to aggregation in the solid state. Solution quantum yields of the polymers were comparable to those reported for the single chromophores used in this study.
Nucleophilic addition-elimination of ortho- or para-substituted phenols to aryl trifluorovinyl ethers (TFVEs) in N,N-dimethylformamide was studied. Using sodium hydride as a base afforded vinyl substitution products R-Ar-O-CF=CF-O-Ar-R', where R or R' = H, Br, OMe, tert-Bu, or Ph. The vinyl substitution products produced mixtures of (Z)/(E)-isomers and this isomer ratio was influenced by substitution with more sterically encumbered phenol nucleophiles. Reactions using caesium carbonate afforded addition products R-Ar-O-CHFCF(2)-O-Ar-R' whereas upon dehydrofluorination using sodium hydride produced vinyl substitution products. The preparation of vinyl substituted and addition products proceeded in overall good isolated yields and were elucidated using (1)H and (19)F NMR, GC-MS, and X-ray analysis. Vinyl substituted products were inert to UV light and chemical reactivity using common polymerization promoters. Thermal activation of the (Z)/(E)-fluoroolefin (-CF=CF-) was observed at an onset of 310 °C in nitrogen using differential scanning calorimetry (DSC) producing insoluble network material. The synthesis, characterization, and mechanism for stereoselectivity are discussed.
Ethers. -The reaction affords vinyl substitution products as (E)/(Z)-mixtures if NaH is used as base. The ratio of the isomers is influenced by the bulkiness of the phenols. In all cases, the (Z)-isomer is the major product. Electronic effects, solvent, or temperature do not affect this ratio. The substitution products are inert to UV light exposure and chemical treatment using common polymerization initiators. If the title reaction is performed in the presence of Cs2CO3, hydrofluorinated ether (IX) is formed. -(MOODY, J. D.; VANDERVEER, D.; SMITH, D. W. J.; IACONO*, S. T.; Org. Biomol. Chem. 9 (2011) 13, 4842-4849, http://dx.doi.org/10.1039/c1ob05041a ; Dep. Chem., Clemson Univ., Clemson, SC 29634, USA; Eng.) -Klein 48-051
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