Photochromic Properties of Novel One-pot Multicomponent Synthesized Tetraarylimidazoles

摘要

Acetic acid mediated synthesis of novel tetraarylimidazoles derivatives has been reported via multicomponent reaction of benzil or phenanthrene-9,10-dione, NH4OAc, vanillin and aniline derivatives under microwave irradiation. Several novel tetraarylimidazole derivatives, phenanthroimidazole and bis-tetraphenylimidazole bearing a 2-methoxyphenol substituent at position 2 of imidazole ring were prepared. The advantages of this method are the one-pot preparation of compounds, in short reaction times (4-7 min) and good yields. All synthesized compounds with a 2-methoxyphenol substituent at position 2 of imidazole ring exhibited good photochromic behavior. The photoisomerization can be performed from ground state to triplet excited state according to TD-DFT calculation. The results showed that the presence of ortho-methoxy substituent to hydroxyl substitution has the greatest effect on photochromic properties of target compounds. Furthermore, a pattern was successfully visualized upon UV light irradiation, which suggested that these compounds can be served as a security ink or an anti-counterfeiting mark for photo printing.