2,7-二溴-4-氨基芴的合成及其光学性质

Synthesis and Otpical Properties of 2,7-Dibromo-4-amino-9H-fluorene

以芴(1)为原料,通过溴代、硝化、还原反应合成了2,7-二溴-4-氨基芴(4),其结构经1H NMR,13C NMR,IR和ESI-MS确证。分别对溴化、硝化和还原反应条件进行优化。结果表明:在最佳溴化反应条件[CHCl3为溶剂,Cu Br2为催化剂,1 90 mmol,n(1)∶n(Cu Br2)∶n(Br2)=1.0∶0.025∶2.89,于0℃反应24 h]下,溴化产物2,7-二溴芴(2)的产率93.8%;在最佳硝化反应条件[2 30 mmol,混合酸(85%硝酸+96%硫酸)为硝化试剂,n(2)∶n(HNO3)=1.0∶4.6,于70℃反应1 h]下,硝化产物2,7-二溴-4-硝基芴(3)的产率94.7%;在最佳还原反应条件(3 30 mmol,Zn/Ca Cl2为还原剂,回流反应4 h)下,4的产率89.5%。运用UV-Vis和荧光光谱初步研究了4的光学性质。结果表明:4的λmax为352.4 nm;在352.4 nm波长激发下,4的λem位于388.4 nm和412.2 nm,光带隙低至2.66 e V。

2,7-Dibromo-4-amino-9H-fluorene（ 4） was synthesized by bromination,nitration and reduction,using 9H-fluorene（ 1） as the starting material. The structures were confirmed by1 H NMR,13 C NMR,IR and ESI-MS. Yield of bromination product,2,7-dibromo-9H-fluorene（ 2）,was 93. 8%under the optimum reaction conditions[CHCl3as the solvent and Cu Br2 as the catalyst,1 90 mmol,n（ 1） ∶ n（ Cu Br2） ∶ n（ Br2） = 1. 0 ∶ 0. 025 ∶ 2. 89,at 0 ℃ for 24 h]. Yield of nitration product,2,7-dibromo-4-nitro-9H-fluorene（ 3）,was 94. 7% under optimum reaction conditions[85% HNO3＋ 96%H2SO4as nitrating reagent,2 30 mmol,n（ 2） ∶ n（ HNO3） = 1. 0 ∶ 4. 6,at 70 ℃ for 1 h]. Yield of4 was 89. 5% under the optimum reaction conditions[Zn / Ca Cl2 as the reducing reagent,3 30 mmol,at reflux for 4 h]. The optical properties of 4 tests indecated that λmaxof 4 was 352. 4 nm,λemwere388. 4 nm and 412. 2 nm（ λex352. 4 nm）,the low optical band gap was 2. 66 e V.