Abstract: The luminescence and photochromism of a series of six salicylaldehyde-derived Schiff base in solution and solid state were investigated by fluorescence spectroscopy 2,2'-[1,2-phenylenebis(nitrilomethylidyne)]bisphenol(1); 2,2'-[1,4-phenylenebis(nitrilomethylidyne)]bis-phenol(2); 2,2'-[1,2-cyclohexanediylbis(nitrilomethylidyne)]bisphenol(3); 2,2'-[1,2-ethane diylbis(nitrilomethylidyne)]bisphenol(4); 2,2'-[1,6-hexanediylbis(nitrilomethylidyne)]bisphenol(5); 2-{[(1-phenylethyl)imino]methylidynephenol}(6). The experimental results show that the fluorescence intensity of Schiff base 1～6 is related to the structure of the conjugated system or the carbon bridge linking the two fluorophores in the molecules. The time-resolved fluorescence spectroscopy of 1, 3—6 show that they are photochromic in either solution or solid state(2 is known as a thermochromic one). The time course fluorescence spectroscopy show that the “macro-response” of Schiff bases 3, 5 and 6 with irradiation is extremely rapid, especially for 5, of which the fluorescence intensity changed by about 70% within 10 s.

Key words: Salicylaldehyde-derived Schiff base, Photochromism, Fluorescence spectroscopy