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本文报道了对一种电子给体-受体化合物(E)-(5-(4-(二苯基胺)苯乙烯基)二噻吩并[2,3-b∶3',2'-d]噻吩基)-2-亚甲基丙二腈(TPA-DCST)的合成与光谱学行为的研究.化合物TPA-DCST的分子结构中含有强电子给体(三苯胺)与强电子受体(二氰基乙烯)两个部分,并由二噻吩并[2,3-b∶3',2'-d]噻吩作为共轭桥将电子给体与受体相连接.在合成方面,采用Wittig反应将三苯胺通过双键与二噻吩并[2,3-b∶3',2'-d]噻吩相连接、醛基化,并与并二腈经Knoevenagel缩合反应合成目标产物.产物通过了核磁氢谱、碳谱、红外以及高分辨率质谱的确认.光谱方面,主要考察了该化合物的吸收与荧光行为.其最大吸收峰位在412 nm左右,归属于7π-7π*跃迁.在非极性溶剂正己烷中表现出来自分子间聚集而形成的聚集态荧光(550nm),并通过了单分子在CTAB胶束([c]=1.02×10-2 mol/L)的发光(460 nm)试验得到验证.溶剂效应表明,该化合物没有出现典型的ICT态的发光现象,其原因在于电子给体与受体相连的共轭桥单元,即二噻吩并[2,3-b∶3',2'-d]噻吩不具有有效的共轭效应.浓度效应与温度效应进一步表明TPA-DCST分子易于产生分子间聚集态的发光.在THF-H2O二元溶剂体系中呈现典型的聚集诱导(AIE)发光现象,发光峰位为692 nm.随着TPA-DCST分子间的聚集程度的增加,聚集态的荧光出现大范围的红移,直至固体发光红移到710 nm.TPA-DCST分子的聚集因素可能来自于疏脂作用、偶极-偶极相互作用等.

A dithieno[2,3-b ∶ 3',2'-d] thiophene bridged D-A compound,(E)-N-4-(2-(5-dicyanovinly-dithieno [2,3-b ∶ 3',2'-d] thiophene-2-yl)-ethenyl)-N,N-diphenylamine (TPA-DCST) was synthesized and its spectroscopic behaviors were studied.In the section of synthesis,TPA-DCST was synthesized by Wittig reaction between two moieties of triphenyl amine and dithieno[2,3-b∶ 3',2'-d] thiophene-2-carbaldehyde,and the following formylation of dithieno [2,3-b∶ 3',2'-d] thiophene moiety and Knoevenagel condensation with malononitrile.The target compound TPA-DCST was fully characterized by 1HNMR,13 CNMR,IR and HRMS.In the section of the spectroscopic behaviors,both absorption and emission behaviors of TPA-DCST were studied.The absorption peak at ～ 412 nm belongs to πr-π* transition.TPA-DCST shows an interesting broad emission at 550 nm in diluted hexane solution,which is regarded as an emission from molecular aggregation,and confirmed by its single peak emission at 460 nm in CTAB micelle solution ([c]=1.02 × 10-2 mol/L).No ICT emission was observed in different polar solvents,because the conjugation bridge,dithieno[2,3-b∶ 3',2'-d]thiophene does not show the effective function of conjugation due to the molecular structure itself.Both concentration effect and temperature effect show that TPA-DCST molecules are easy to give the emission from molecular aggregation.In THF-H2O binary mixture solution,TPA-DCST shows typical AIE state emission at 692 nm.With increasing aggregation of TPA-DCST molecules,the emission peak shows strong bathochromic shift,from 550 nm in hexane solution to 710 nm in solid.The driving force of the aggregation may be from hydrophobic effect and dipole-dipole interaction of TPA-DCST molecules.