State Key Laboratory of Materials-Oriented Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, College of Chemistry and Chemical Engineering, Nanjing Tech University, Nanjing 211816, China.
Inorg Chem. 2023 Jun 5;62(22):8655-8662. doi: 10.1021/acs.inorgchem.3c00813. Epub 2023 May 24.
Heterogeneous solid base catalysts are highly expected due to their high activity and environmentally friendly nature in a variety of reactions. However, the catalytic activity of traditional solid base catalysts is controlled by external factors (such as temperature and pressure), and regulation of the activity by in situ changing their own properties has never been reported. Herein, we report a smart solid base catalyst by chemically anchoring the photoresponsive azobenzene derivative -phenylazobenzoyl chloride (PAC) onto the metal-organic framework UiO-66-NH (UN) for the first time, which can regulate the catalytic activity through remote control of external light. The prepared catalysts have a regular crystal structure and photoresponsive properties. It is fascinating that the configuration of PAC can be isomerized easily during UV- and visible-light irradiation and resulted in regulation of the catalytic activity. In the Knoevenagel condensation of 1-naphthaldehyde and ethyl cyanoacetate to ethyl 2-cyano-3-(1-naphthalenyl)acrylate, the optimal catalyst shows up to 56.2% of change after / isomerization, while the change of the yield over UN is negligible. The regulated catalytic behavior can be assigned to the steric hindrance change of the catalysts under external light irradiation. This work may shed light on the design and construction of smart solid base catalysts with tailorable properties for various reactions.
由于在各种反应中具有高活性和环境友好性，异相固体碱催化剂受到了高度期待。然而，传统固体碱催化剂的催化活性受到外部因素（如温度和压力）的控制，通过原位改变其自身性质来调节活性的方法从未有过报道。在此，我们首次通过化学接枝将光响应的偶氮苯衍生物 - 苯偶氮苯甲酰氯（PAC）固定到金属-有机骨架 UiO-66-NH（UN）上，制备了一种智能固体碱催化剂，可通过外部光的远程控制调节催化活性。所制备的催化剂具有规则的晶体结构和光响应性能。有趣的是，PAC 的构型在紫外光和可见光照射下很容易发生异构化，从而调节了催化活性。在 1-萘醛和氰基乙酸乙酯的 Knoevenagel 缩合反应中，最优催化剂在异构化后表现出高达 56.2%的变化，而 UN 的产率变化可以忽略不计。调节后的催化行为可归因于催化剂在外部光照下的空间位阻变化。这项工作可能为设计和构建具有可调节性质的用于各种反应的智能固体碱催化剂提供思路。
