Cao Xinhua, Meng Luyan, Li Zhenhua, Mao Yueyuan, Lan Haichuang, Chen Liming, Fan Yang, Yi Tao
Department of Chemistry, Fudan University , Shanghai 200433, China.
Langmuir. 2014 Oct 7;30(39):11753-60. doi: 10.1021/la503299j. Epub 2014 Sep 25.
Two low molecular weight gelators containing 4-ethynyl-1,8-naphthalimide groups with large conjugated structure via different length of alkyl chains were synthesized and fully characterized. The gelation properties, structural character, and fluorescence of the gels were investigated via methods of scanning electron microscopy, X-ray diffraction, and spectral studies. The gelators have high fluorescence quantum yields in both solution and solid state. Interestingly, the wavelength of the fluorescent emission in the reversible sol-gel transition process of the gels has a large red-shift of 80 nm in DMF, which is extremely sparse for 1,8-naphthalimide derivatives in the literature. The intermolecular π-π stacking between naphthalimide is suggested to be the main driving force for the gel formation and fluorescent variation by means of temperature-dependent (1)H NMR study and theoretical calculation.
合成了两种含有4-乙炔基-1,8-萘二甲酰亚胺基团且具有通过不同长度烷基链相连的大共轭结构的低分子量凝胶因子，并对其进行了全面表征。通过扫描电子显微镜、X射线衍射和光谱研究等方法，研究了凝胶的凝胶化性质、结构特征和荧光特性。这些凝胶因子在溶液和固态下均具有较高的荧光量子产率。有趣的是，在二甲基甲酰胺（DMF）中，凝胶在可逆溶胶-凝胶转变过程中荧光发射波长有80nm的大红移，这在文献中对于1,8-萘二甲酰亚胺衍生物来说是极为罕见的。通过变温核磁共振氢谱（¹H NMR）研究和理论计算表明，萘二甲酰亚胺之间的分子间π-π堆积是凝胶形成和荧光变化的主要驱动力。
