Synthesis and Spectra Characteristics of Novel 3-(para-Bromophenyl)-7-(substituted vinyl) Coumarins

Five new coumarin derivatives (5a, 5b, 5c, 5d, 5e) with extending para-bromophenyl at the 3-position and substituted vinyl at the 7-position were synthesized and characterized by FT-IR, 1H NMR, and element analysis. The absorption and fluorescence characteristics of compounds 5a, 5b, 5c, 5d, 5e showed significant dependences on its molecular structure, which possessed large Stokes shifts (up to 8309 cm−1) and high fluorescence quantum yield (up to 0.80) in CH2Cl2. These advantageous spectral properties should allow use in many areas.