Direct prediction of the solid-state fluorescence wavelength of 1-furyl/thienyl-2-arylethylene with the push-pull effect determined by NMR

Although it is known that push-pull effect of substituents affect the fluorescence emission of D-pi-A molecules, the quantitative relationship between the push-pull effect and the fluorescence emission wavelength Em (or wavenumber nu(em)) has not been reported up to now. Here we report the direct predicting the solid-state fluorescence wavelength of a kind of D-pi-A molecules via using the push-pull effect of substituents determined by NMR. Starting from the stilbene-like molecules, 1-furyl/thienyl-2-arylethylene XCH = CHArY (abbreviated XAEY), the push-pull effect were determined via the chemical shifts difference Delta delta(C) of the carbon in bridging bond CH=CH. Then the solid-state fluorescence wavenumber nu(em) of XAEY were correlated to the push-pull effect. The results show: (1) The nu(em) of XAEY can be directly predicted with the push-pull effect Delta delta(C) of the substituents. (2) The influence of Delta delta(C) originating from para-Y on the nu(em) is different from that of Delta delta(C) originating from meta-Y on the nu(em) (3) Compared with the para-Y, the influence of the Delta delta(C) of meta-Y on the nu(em) is more potent.