Tong Jing, Wang Jinfeng, Shen Xiaoshuang, Zhang Hui, Wang Yao, Fang Qiang, Chen Liyong
Department of Pharmaceutical Engineering, Bengbu Medical College, Bengbu, Anhui 233030, P. R. China.
State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, P. R. China.
Inorg Chem. 2021 Jul 19;60(14):10715-10721. doi: 10.1021/acs.inorgchem.1c01406. Epub 2021 Jun 29.
Schiff bases that are generally formed from condensation reactions of aldehydes (or ketones) and amino groups could also be produced by a photodriven one-pot tandem reaction between alcohols and nitro compounds, in our case. Herein, TiO porous cages derived from NH-MIL-125 by a self-sacrificing template route are used to study the organic transformation and exhibit 100% conversion efficiency of nitrobenzene and 100% selectivity for Schiff bases in the system of benzyl alcohol (5 mL) and nitrobenzene (41 μL) upon light irradiation, but hydrogen by dehydrogenation of benzyl alcohol cannot be detected. Successful occurrence of the organic transformation is mainly attributed to Ti(III)-oxygen vacancy associates. Surface oxygen vacancy-related Ti(III) sites are responsible for binding with nitro groups, and low-coordinated Ti sites selectively adsorb hydroxyl groups of benzyl alcohol. The Ti(III) and oxygen vacancy associates capture photogenerated electrons for achievement of multielectron reduction of nitrobenzene and the subsequent Schiff base condensation reaction with the as-formed benzaldehyde.
在我们的研究中，席夫碱通常由醛（或酮）与氨基的缩合反应形成，也可以通过醇与硝基化合物之间的光驱动一锅串联反应来制备。在此，通过自牺牲模板路线从NH-MIL-125衍生而来的TiO多孔笼用于研究有机转化，在光照下，在苯甲醇（5 mL）和硝基苯（41 μL）体系中，对硝基苯的转化率为100%，对席夫碱的选择性为100%，但未检测到苯甲醇脱氢产生的氢气。有机转化的成功发生主要归因于Ti(III)-氧空位缔合体。表面氧空位相关的Ti(III)位点负责与硝基结合，低配位的Ti位点选择性吸附苯甲醇的羟基。Ti(III)和氧空位缔合体捕获光生电子，以实现硝基苯的多电子还原以及随后与生成的苯甲醛的席夫碱缩合反应。
