咔唑类A-π-D-π-A型红光及近红外荧光染料的发光性质调控

发布时间：2018-05-30 01:14

本文选题：A-π-D-π-A型 + 近红外荧光染料　；参考：《太原理工大学》2017年硕士论文

【摘要】：近年来,红光及近红外荧光染料在光电材料、生物成像、荧光探针、信息加密等方面都有巨大的应用需求,而有机红光及近红外荧光染料具有分子结构灵活易调控、摩尔吸光系数相对较高、生物相容性好、价格低廉等优点而成为当前科学研究的热点。本论文设计合成了一系列分别以丙二腈、茚二酮和三氰基呋喃衍生物(TCF)为电子受体,以己基和异辛基为N-烷基取代的咔唑类A-π-D-π-A型有机荧光染料(h-CPDM/i-CPDM、h-CPBI/iCPBI和h-CPBT/i-CPBT)。通过紫外-可见吸收光谱、荧光发射光谱和瞬态荧光光谱、x射线衍射、差示扫描量热法及扫描电子显微镜等研究了染料在溶液及聚集态下的发光行为,包括溶剂化效应、聚集诱导发光性质,以及机械响应发光性质。研究结果证明:1.随着电子受体的吸电子能力增强,分子HOMO能级变化不大,LUMO能级逐渐降低,导致分子能隙减小,发光颜色红移。2.溶剂化效应:h-CPDM/i-CPDM和h-CPBI/i-CPBI均具有显著的溶剂化效应,从非极性的正己烷到强极性的DMSO中,h-CPDM/i-CPDM的发光颜色覆盖了从蓝色到橘红色,发光波长分别红移了49/68 nm;h-CPBI/i-CPBI的发光颜色覆盖了从蓝色到红色,红移波长达到168/176 nm。这种显著的溶剂化效应归因于它们固有的分子内电荷转移(Intramolecular Charge Transfer,ICT)性质。3.聚集诱导发光性质:化合物h-CPDM/i-CPDM以及h-CPBI在四氢呋喃和水的混合溶液中,分子在J-聚集过程中π-π堆积作用较强,所以都存在聚集荧光猝灭现象。而化合物i-CPBI因其异辛基支链的空间位阻较大以及咔唑基团的刚性较强,在聚集过程中抑制了分子的π-π堆积作用,同时限制了分子的自由旋转而减少了非辐射途径,所以表现出聚集诱导发光(Aggregation Induced Emission,AIE)性质。4.机械响应发光性质:以丙二腈为电子受体的h-CPDM和i-CPDM研磨前后样品的荧光量子产率分别从0.9%(λmax 678 nm)和0.3%(λmax 661 nm)增加到8.7%(λmax 610nm)和25.6%(λmax 596 nm);以茚二酮为电子受体的h-CPBI和i-CPBI研磨前后样品的荧光量子产率分别从0.6%(λmax 713 nm)和0.3%(λmax 648nm)增加到18.6%(λmax 625 nm)和29.4%(λmax 628 nm);以TCF为电子受体的h-CPBT和i-CPBT研磨前后样品的荧光量子产率分别从0.82%(714nm)和0.85%(717 nm)增加到5.41%(729 nm)和5.27%(731 nm),均实现了机械力诱导的荧光“开启”。它们的XRD和DSC数据结果表明,通过机械研磨使得h-CPDM/i-CPDM和h-CPBI/i-CPBI的分子聚集态的有序性被打破,从而实现了荧光增强。荧光寿命结果也表明,研磨前后产生了相转变过程。
[Abstract]:In recent years, red and near infrared fluorescent dyes have great applications in photoelectric materials, biological imaging, fluorescence probes, information encryption, etc., while organic red and near infrared fluorescent dyes have flexible molecular structure. The advantages of relatively high molar absorptivity, good biocompatibility and low price have become the focus of current scientific research. In this paper, a series of carbazoles A- 蟺 -D蟺 -A organic fluorescent dyes with malonitrile, ninhydrin and tricyanofuran derivatives as electron receptors and hexyl and isooctyl as N-alkyl substituents have been designed and synthesized, respectively. The luminescence behavior of dyes in solution and aggregation state was studied by UV-Vis absorption spectra, fluorescence emission spectra and transient fluorescence spectra, X-ray diffraction, differential scanning calorimetry and scanning electron microscope. Aggregation induced luminescence and mechanical response luminescence. The result of the study proves that 1: 1. With the enhancement of the electron absorption ability of the electron receptor, the energy level of the molecular HOMO decreases gradually, which leads to the decrease of the molecular energy gap and the red shift of the luminescence color. Solvation effect: h-CPDM / I-CPDM and h-CPBI/i-CPBI have significant solvation effects, ranging from nonpolar n-hexane to highly polar DMSO with luminous colors covering the range from blue to orange. The luminous wavelengths are redshift 49 / 68 nm / h ~ (h-CPBI / i-CPBI), respectively, and the red shift wavelength is 168 / 176nm ~ (-1), covering the color from blue to red. This remarkable solvation effect is attributed to their intrinsic intramolecular charge transfer Charge transfer property. Aggregation induced luminescence: in the mixed solution of tetrahydrofuran and water, the 蟺-蟺 accumulation of compounds h-CPDM/i-CPDM and h-CPBI is stronger in the process of J- aggregation, so there exists the phenomenon of fluorescence quenching of aggregation. Because of the large steric hindrance of isooctyl branched chain and the strong rigidity of carbazole group, the compound i-CPBI inhibited the 蟺-蟺 accumulation of molecule during the aggregation process, and limited the free rotation of molecule, thus reducing the non-radiation pathway. Therefore, the agglomeration induced luminescence Induced emission of AIE.4. Photoluminescence properties of mechanical response: fluorescence quantum yields of h-CPDM and i-CPDM samples with malonitrile as electron acceptor increased from 0.9g (位 max 678nm) and 0.3um (位 max 661nm) to 8.7 (位 max 610nm) and 25.6N / m (位 max 596nmm), respectively; h-CPBI and i-CPBI with ninhydrin as electron acceptor before grinding The fluorescence quantum yields of the samples increased from 0. 6 (位 max 713 nm) and 0. 3 (位 max 648 nm) to 18. 6 (位 max 625 nm) and 29. 4 (位 max 628 nm), respectively. The fluorescence quantum yields of h-CPBT and i-CPBT polished samples with TCF as electron acceptor increased from 0. 822 ~ 714 nm and 0. 85 ~ 717 nm to 5. 41 ~ 729 nm and 5. 27 ~ 731 nm respectively. The mechanically induced fluorescence is now on. Their XRD and DSC data show that the order of the molecular aggregates of h-CPDM/i-CPDM and h-CPBI/i-CPBI is broken by mechanical grinding, thus the fluorescence enhancement is realized. The fluorescence lifetime also shows that phase transition occurs before and after grinding.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ617.3

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