【作者】 董小丽；

【导师】 杜新贞；

【作者基本信息】 西北师范大学 ， 分析化学， 2008， 硕士

【摘要】 第一章:本章介绍了环糊精超分子化学领域的基本概况及其研究进展。同时介绍了TICT化合物对二甲氨基苯甲酸酯类化合物在光物理和光化学领域的研究发展历程,及其荧光传感和分子识别方面的应用。对4-(N,N-二甲氨基)苯甲酸-3甲基丁酯(IADMAB)的结构性质和其在防晒剂方面的应用情况做了简要介绍。第二章:本章通过紫外吸收光谱和荧光光谱对IADMAB在不同极性介质中的光谱、光物理行为进行了具体的研究。结果表明,随溶剂极性的增大,IADMAB的最大吸收波长红移,精细结构消失,吸收带逐渐变的平滑,在醇水混合溶剂中也出现了类似的变化趋势。在荧光光谱中,荧光峰向长波方向移动,激发态分子发生电荷转移,与基态相比偶极矩变大,出现双重荧光,同时相对荧光强度也随之减小。这一实验结果将为设计新的以光诱导电荷转移为基础的荧光传感提供理论依据,IADMAB可以用作荧光探针。第三章:本章以IADMAB为荧光体,运用荧光光谱、紫外吸收光谱、核磁共振光谱和正己醇竞争包合实验研究了IADMAB与α-CD、β-CD、γ-CD的包合作用。结果表明:IADMAB都可以和α-CD、β-CD、γ-CD三种环糊精发生包合作用。IADMAB与α-CD、β-CD在水溶液里可行成2:1的主-客体包合物,与γ-CD在所研究的浓度范围内可能生成了2:2型主-客体的包合物,随γ-CD浓度的增大,没有观察到IADMAB的TICT荧光。这说明了环糊精空腔尺寸的大小是影响IADMAB与α-CD、β-CD、γ-CD包合作用的主要因素。第四章:本章用分子光谱法研究了α-CD与4-(N,N-二甲氨基)苯甲酸(DMABA)、4-(N,N-二甲氨基)苯甲酸乙酯(EDMAB)、4-(N,N-二甲氨基)苯甲酸-3甲基丁酯(IADMAB)和4-(N,N-二甲氨基)苯甲酸-2’-乙基己酯(EHDMAB)分子间的包合作用,比较了α-CD与DMABA、EDMAB、IADMAB和EHDMAB所形成包合物的组成和结合位点,根据主-客体分子的大小和结构探讨了相应的包合机理,具有较短碳链的EDMAB和IADMAB分子是4-(N,N-二甲氨基)端优先进入α-CD空腔,而对带有疏水性长碳链的EHDMAB分子是柔性的异辛基端优先进入α-CD空腔。因此,α-CD与EDMAB、IADMAB和EHDMAB形成了不同类型的1:1型主-客体包合物,随着溶液中α-CD浓度的增大,4-(N,N-二甲氨基)苯甲酸酯分子未被包合部分可再结合一个α-CD形成2:1型的主-客体包合物。更多还原

【Abstract】 Chapter 1: The recent advances in supramolecular inclusion complexes of cyclodextrins have been reviewed. The structure, property and the appliction of Isoamyl-4-(N, N-dimethylamino)-benzoate (IADMAB) in sun-screening products and its molecular recongnition and fluorescent sensing based on the TICT mechanism were briefly described.Chapter 2: Ultraviolet-visible absorption spectral properties and fluorescence spectral properties of IADMAB in different solvents were studied at room temperature. The results indicate that the main absorption peaks are located in 290-320nm and the absorption maximum shifts to the red with increasing solvent polarity,This kind of change is the same as the IADMAB in alcohol/water mixed solvents. Dipole moment in excited state was larger than that in ground state, which is due to twisted intramolecular charge transfer. It was found that with increasing solvent polarity the dual fluorescence occurred and the TICT emssion shifted to long wavelength at the same time. And the flourescence intendity decreased. This found would provide a theroretic gist based on intramolecular charge transfer for flourescent sensing.Chapter 3: Fluorescence of isoamyl 4-dimethylaminobenzoate (IADMAB) has been examined to characterize complexation geometry of rod-shaped isoamyl 4-dimethylaminobenzoate with inα-cyclodextrin (α-CD),β-cyclodextrin (β-CD) andγ-cyclodextrin (γ-CD). NMR measurements reveal that IADMAB forms 1:2 complexes withα-CD andβ-CD and 2:2 complexes withγ-CD in an aqueous solution, respectively. Both the amyl chain and the aromatic moiety were included inside the cavity of cyclodextrins. A comparison of molecular structures and sizes was made to elucidate the complexation geometry of rod-shaped IADMAB with different cyclodextrins. The 4-dimethylaminobenzoate moiety of IADMAB in inclusion complexes probably projects out of the cavity to a greater extent because of the small cavity ofα-CD and exhibits distinct dual fluorescence. As compared with that ofα-CD, the cavity ofβ-CD is large enough to completely accommodate the dimethylaminobenzoate moiety. The dimethylamino group in the complex would experience non-polar environment and exclusively show very strong LE emission. In the presence ofγ-CD, it was assumed that two dimethylamino groups of IADMAB molecules are included in the same cavity ofγ-CD with their amyl chains penetrating into anotherγ-CD at the primary hydroxyl end and secondary hydroxyl end, respectively. The cavity size effect on the TICT emission of IADMAB is very important.Chapter 4: The inclusion of DMABA, EDMAB, IADMAB and EHDMAB in the cavity ofα-CD was examined by means of molecular spectra. The stoichiometry and binding sites ofα-CD to DMABA, EDMAB, IADMAB and EHDMAB were compared. The mechanism of inclusion was discussed on the basis of molecular structures and sizes. The 4-(N, N-dimethylamino) group is preferentially included inside the cavity ofα-CD in the case of EDMAB and IADMAB with a shorter hydrocarbon chain. On the contrary, the flexible hydrophobic isooctyl chain of EHDMAB preferentially penetrates into the cavity ofα-CD and the 4-(N,N-dimethylamino) group protrudes outside the cavity. Thusα-CD forms different types of 1:1 host-guest inclusion complexes with EDMAB, IADMAB and EHDMAB. With increasing concentration ofα-CD, anotherα-CD is capable of incorporating the other part of EDMAB, IADMAB and EHDMAB whose opposite end is already located inside the cavity ofα-CD. The 2:1 host-guest inclusion complexes are formed in aqueous solution.更多还原