对位氨基能显著提高D-A-D型化合物的双光子吸收性能

报道了具有典型D-A-D型共轭结构的反式2,5-二氰基-1,4-二(4'-甲氧基苯乙烯基)苯(MOS-CN), 2,5-二氰基-1,4-二(4'-二甲胺基苯乙烯基)苯(MAS-CN)和1,4-二(4'-甲氧基苯乙烯基)苯(MOS)的合成. 用核磁、红外和元素分析进行了表征. 测试了紫外吸收光谱、单光子荧光光谱、双光子荧光光谱、双光子吸收系数及双光子吸收截面. 在800 nm的飞秒脉冲激光激发下, 化合物MOS-CN, MAS-CN和MOS分别发出很强的绿色、黄色和蓝色上转换荧光. 化合物MOS-CN, MAS-CN和MOS的最大吸收波长、单光子发射波长、双光子诱导荧光波长、荧光量子产率、双光子吸收系数、双光子吸收截面及双光子荧光寿命各分别是393, 473, 367 nm; 470, 569, 434 nm; 475, 574, 438 nm; 0.12, 0.72, 0.21; 0.8, 5.3, 0.3 cm/GW; 270, 1790, 101 GM; 140 ps, 1.32 ns, 54 ps. MAS-CN的双光子吸收截面是MOS-CN的6.63倍, MOS-CN的双光子吸收截面是MOS的2.67倍, 表明对位氨基显著地提高了化合物的双光子吸收性能, 氰基也较大地提高了双光子吸收截面.

Prominent Improvement of the Two-photon Absorption Ability of D-A-D Compounds due to Contraposition Amino Group

The syntheses of 2,5-dicyano-1,4-bis-(4'-methoxystyryl)benzene (MOS-CN), 2,5-dicyano-1,4- bis-(4'-dimethylaminostyryl)benzene (MAS-CN) and 1,4-bis-(4'-methoxystyryl)benzene (MOS) with typical D-A-D conjugation structure were reported. Their structures were characterized by ¹H NMR, IR and elemental analyses. Linear absorption, single-photon induced fluorescence, two-photon induced fluorescence and two-photon absorption cross section (σ₂) are experimentally studied. While pumped with 800 nm laser irradiation, these three compounds showed strong two-photon induced green, yellow and blue fluorescence, respectively. The maximum absorption wavelengths, single-photon emission wavelengths, two-photon induced fluorescence wavelengths, fluorescence quantum yields, two-photon absorption coefficients, two-photon absorption cross sections (σ₂) and two-photon fluorescence lifetimes of MOS-CN, MAS-CN and MOS were 393, 473, 367 nm; 470, 569, 434 nm; 475, 574, 438 nm; 0.12, 0.72, 0.21; 0.8, 5.3, 0.3 cm/GW; 270, 1790, 101 GM; 140 ps, 1.32 ns, 54 ps, respectively. The σ₂ of MAS-CN was 6.63 times that of MOS-CN, and σ₂ of MOS-CN was 2.67 times that of MOS, which manifested that a contraposition amino group could prominently improve the two-photon absorption ability of such D-A-D compounds, and cyano groups could also make a great contribution to σ₂ .