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).