Zhu Zhong-Hong, Bi Changjiang, Zou Hua-Hong, Feng Guangxue, Xu Shuping, Tang Ben Zhong
State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China.
State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun, 130012, China.
Adv Sci (Weinh). 2022 May;9(16):e2200850. doi: 10.1002/advs.202200850. Epub 2022 Mar 31.
Luminescent metal-organic frameworks (MOFs) are appealing for the design of smart responsive materials, whereas aggregation-induced emission (AIE) fluorophores with twisted molecular rotor structure provide exciting opportunities to construct MOFs with new topology and responsiveness. Herein, it is reported that elongating AIE rotor ligands can render the newly formed AIE MOF (ZnETTB) (ETTB = 4',4''',4''''',4'''''''-(ethene-1,1,2,2-tetrayl)tetrakis(([1,1'-biphenyl]-3,5-dicarboxylic acid))) with more elasticity, more control for intramolecular motion, and specific amide-sensing capability. ZnETTB shows specific host-guest interaction with amide, where N,N-diethylformamide (DEF), as an example, is anchored through CH···O and CH···π bonds with Zn cluster and ETTB ligand, respectively. DEF anchoring reduces both the distortion level and the intramolecular motions of ETTB ligand to lead a blueshifted and intensified emission for DEF ∈ ZnETTB. Moreover, amide anchoring also affords the DEF ∈ ZnETTB with the excellent thermofluorochromic behavior, and further increases the piezofluorochromic sensitivity at low-pressure ranges on the basis of its elastic framework. This work is one of the rare examples of amide-responsive smart materials, which shall shed new lights on design of smart MOFs with twisted AIE rotors for further sensing and detection applications.
发光金属有机框架材料（MOFs）在智能响应材料设计方面颇具吸引力，而具有扭曲分子转子结构的聚集诱导发光（AIE）荧光团为构建具有新拓扑结构和响应性的MOFs提供了令人兴奋的机遇。在此，据报道，延长AIE转子配体可使新形成的AIE MOF（ZnETTB）（ETTB = 4'，4'''，4''''，4''''''' - （乙烯 - 1，1，2，2 - 四亚基）四（（[1，1'-联苯] - 3，5 - 二羧酸）））具有更大的弹性、对分子内运动更强的控制能力以及特定的酰胺传感能力。ZnETTB与酰胺表现出特定的主客体相互作用，例如，N，N - 二乙基甲酰胺（DEF）分别通过CH···O和CH···π键与Zn簇和ETTB配体锚定。DEF的锚定降低了ETTB配体的扭曲程度和分子内运动，导致DEF ∈ ZnETTB的发射发生蓝移并增强。此外，酰胺锚定还赋予DEF ∈ ZnETTB优异的热荧光变色行为，并基于其弹性框架在低压范围内进一步提高压致荧光变色灵敏度。这项工作是酰胺响应智能材料的罕见实例之一，将为设计具有扭曲AIE转子的智能MOFs以用于进一步的传感和检测应用提供新的思路。
