Synthesis,Photoluminescence and Stimulus-responsiveness Properties of Bridged Fluorinated Tetraphenylethene Compounds
Six fluorinated bis-tetraphenylethene(bis-FTPE)compounds were synthesized through the condensation of tetraphenylethene-based formaldehyde and ethylenediamine and further reduction and then acidification.The bridging groups are imine(compounds 1 and 2),amine(compounds 3 and 4)and quaternary ammonium salt(compounds 5 and 6)moieties,respectively.It has been found that the fluorine atom(s),different bridging groups and substitution positions exhibit tuning effect on the luminescence properties of the compounds.The emission wavelengths of compounds 1 and 2 are essentially the same as that of the parent tetraphenylethene(TPE),and the luminescence quantum yield of compound 2(38%)is higher than that of TPE(23%),indicating that the bridge/fluorination strategy can precisely maintain the emission wavelength of TPE while improving the emission intensity.Compounds 1,2,5 and 6 have mechanochromic luminescence properties and compounds 3 and 4 exhibit acidochro-mic luminescence properties.Paper strips made of compound 3 can readily distinguish hydrochloric acid,acetic acid and trifluoroacetic acid by the emission color.These results suggest that the fluorination/bridge strategy may be applied to synergistically and precisely tune the emission and stimulus-responsiveness properties of such compounds via intra-and intermolecular interactions to adjust the molecular packing and the rotations of the phenyl groups of these compounds.
国家科技期刊平台
NSTL
万方数据
