Wang Dan, Li Shu-Mu, Zheng Jian-Quan, Kong Duan-Yang, Zheng Xiang-Jun, Fang De-Cai, Jin Lin-Pei
Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University , Beijing 100875, P. R. China.
Key Laboratory of Green Printing, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, P. R. China.
Inorg Chem. 2017 Jan 17;56(2):984-990. doi: 10.1021/acs.inorgchem.6b02784. Epub 2017 Jan 5.
2-(Trityliminomethyl)-quinolin-8-ol (HL) and its Zn(II) complex were synthesized and characterized by single-crystal X-ray diffraction. HL is an unsymmetrical molecule and coordinated with Zn(II) ion to form ZnL in the antiparallel-mode arrangement via Zn-O (hydroxyl group) and Zn-N (quinoline ring) of HL. A high degree of ZnL molecules ordering stacking is formed by the coordination bonds and intermolecular π-π interactions, in which head-to-tail arrangement (J-mode stacking) for L is found. HL is nonfluorescent and ZnL is weakly fluorescent in THF. The fluorescence emission of ZnL enhances in THF/HO as HO% (volume %) is above 60% and aggregates particles with several hundred nanometers are formed, which is confirmed by DLS data and TEM images. The J-aggregates stacking for L in ZnL results in aggregation-induced emission enhancement (AIEE) for ZnL in THF/HO. Theoretical computations based on B3LYP/6-31G(d, p) and TD-B3LYP/6-31G(d, p) methods were carried out. ESIPT is the supposed mechanism for fluorescent silence of HL, and fluorescence emission of ZnL is attributed to the restriction of ESIPT process. The oscillator strength of ZnL increases from 0.017 for monomer to 0.032 for trimer. It indicates that a high degree of ZnL molecules ordering stacking in THF/HO is of benefit to fluorescence enhancement. HL is an ESIPT-coupled AIEE chemosensor for Zn(II) with high selectivity and sensitivity in aqueous medium. HL can efficiently detect intracellular Zn(II) ions because of ESIPT-coupled AIEE property of ZnL in mixed solvent.
合成了2-(三苯甲基亚氨基甲基)-喹啉-8-醇(HL)及其锌(II)配合物，并通过单晶X射线衍射对其进行了表征。HL是一个不对称分子，通过HL的Zn-O(羟基)和Zn-N(喹啉环)与锌(II)离子配位，以反平行模式排列形成ZnL。通过配位键和分子间π-π相互作用形成了高度有序堆积的ZnL分子，其中发现L为头对尾排列(J模式堆积)。HL在四氢呋喃中无荧光，ZnL在四氢呋喃中荧光较弱。当水的体积百分比(HO%)高于60%时，ZnL在四氢呋喃/水中的荧光发射增强，并形成数百纳米的聚集颗粒，动态光散射数据和透射电子显微镜图像证实了这一点。ZnL中L的J聚集体堆积导致ZnL在四氢呋喃/水中的聚集诱导发光增强(AIEE)。基于B3LYP/6-31G(d, p)和TD-B3LYP/6-31G(d, p)方法进行了理论计算。ESIPT被认为是HL荧光沉默的机制，ZnL的荧光发射归因于ESIPT过程的受限。ZnL的振子强度从单体的0.017增加到三聚体的0.032。这表明在四氢呋喃/水中高度有序堆积的ZnL分子有利于荧光增强。HL是一种在水介质中对锌(II)具有高选择性和灵敏度的ESIPT耦合AIEE化学传感器。由于ZnL在混合溶剂中的ESIPT耦合AIEE性质，HL可以有效地检测细胞内的锌(II)离子。
