1,3,4-噁二唑衍生物的双光子吸收和双光子泵浦荧光

Two-Photon Absorption and Two-Photon Excited Fluorescence of 1,3,4-Oxadiazole Derivatives

依据“推电子基-共轭中心-拉电子基-共轭中心-推电子基”的模型将电荷传输型1,3,4-噁二唑环嵌入芳香共轭体中,通过Wittig-Horner反应合成了2种对称型强双光子吸收和双光子诱导荧光分子2,5-二[4-(2-芳基乙烯基)苯基]-1,3,4-噁二唑.它们的氯仿溶液在锁模Nd:YAG激光器800nm激光照射下,发射出很强的双光子上转换荧光,其最强荧光分别在波长507和475nm.采用非线性透过率法测得其双光子吸收截面分别为1.07×10-46和6.6×10-47cm4?s?photon-1.这2个对称型D-π-A-π-D生色分子从激发端基到π共轭桥的有效能量传输,对双光子吸收和双光子荧光发射能力贡献较大.

Two symmetrical 2,5-bis[4-（2-arylvinyl）phenyl]-1,3,4-oxadiazoles that exhibit strong two-photon absorption and enhanced two-photon excited fluorescence were designed and synthesized based on ＂push-core-pull-core-push＂ molecules built from embedding electron-transporting 1,3,4-oxadiazole in aromatic conjugated system through Wittig-Horner reaction. Pumped by nanosecond laser at 800 rim, strong up-conversion emissions with the central wavelength at 507 and 475 nm in the solution of CHC13 have been observed. Their two-photon absorption cross-sections obtained by nonlinear transmission method are 1.07 × 10^-46 and 6.6×10^-47 cm^4·s·photon^-1. A very effective energy transfer from the excited terminal units to the π-conjugated bridging units of the two symmetrical D-π-A-π-D chromophores make the dominant contribution to the two-photon absorption and two-photon excited fluorescence.