2‐Amino‐3‐naphthylacrylonitrile Derivatives as Green Luminance Dyes

Three derivatives of 2-amino-3-naphthylacrylonitrile 2 similar to 4 were synthesized as potential green luminance dyes. The green emission is derived from a charge transfer transition, which exhibits an apparent solvatochromic effect. The crystal structures of derivatives 2 and 3 were resolved by X-ray diffraction analyses. The diphenylamino derivative 2 was found in monoclinic P-21/n space group with a = 10.032(2), b = 17.034(5), c = 12.143(6), and beta = 112.02(3)degrees. The carbazyl derivative 3 was found in triclinic P-1 space group with a = 8.890(3), b = 9.296(6), c = 12.209(5), and alpha = 98.89(4)degrees, beta = 93.46(3)degrees, gamma = 116.47(4)degrees. The amino group in 2 forms a better resonance with acrylonitrile group than that in 3. The electronic nature of the amino group is responsible for the spectral difference among three compounds. The effect is verified by ab initio molecular modeling.