Synthesis, crystal structure and two-photon excited fluorescence properties of three aurone derivatives

Three aurone derivatives, Z -2-[(4- N , N -dimethylaminophenyl)methylene] benzofuran-3-one ( 1 ), Z -2-[( N -ethylcarbazol-3-yl)methylene]benzofuran-3-one ( 2 ) and Z -2-[(pyren-1-yl)methylene]benzofuran-3-one ( 3 ) have been synthesized by the cyclization of 2′-hydroxychalcones. Their crystal structure, single- and two-photon related absorption and fluorescence properties have been examined. Pumped by 860   nm laser pulses in femtosecond regime, the compounds exhibit strong yellow–green two-photon excited fluorescence at 539   nm ( 1 ), 505   nm ( 2 ) and 524   nm ( 3 ) in THF with two-photon absorption (TPA) cross-section being 1536GM ( 1 ), 608GM ( 2 ) and 236GM ( 3 ).