Liu Wansheng, Yang Yi, Yang Xiaojie, Peng Yun-Lei, Cheng Peng, Zhang Zhenjie, Chen Yao
College of Chemistry, Nankai University, Tianjin 300071, China.
Renewable Energy Conversion and Storage Center, Nankai University, Tianjin 300071, China.
ACS Appl Mater Interfaces. 2021 Dec 15;13(49):58619-58629. doi: 10.1021/acsami.1c17925. Epub 2021 Dec 3.
Photocatalysis is a powerful and versatile tool widely applied in the areas of synthesis chemistry. However, most of the photocatalysts currently used are homogeneous catalysts, which inevitably face issues such as product-catalyst separation and recyclability. Addressing this challenge, we utilized a homogeneous Ru photocatalyst as a structure-directing template to fabricate a series of isostructural photocatalyst-encapsulating metal-organic frameworks (photocatalyst@MOFs) with high porosity, robustness, and photocatalyst loading. The regular channels of MOF can disperse the encapsulated photocatalysts, promote the mass transfer of substrates and products, and provide an outstanding substrate confinement effect, thereby dramatically improving the catalytic activity and excellent recyclability toward valuable organic reactions. For instance, the MOF photocatalysts can catalyze the asymmetric Mannich reaction with ketones with high yields and excellent enantioselectivities (up to 99% ee), better than the reported photocatalyst. Significantly, this was the first case that heterogeneous MOF-based photocatalyst can catalyze the asymmetric Mannich reaction without cocatalysts under room temperature and visible light. This work not only explores an avenue to prepare heterogeneous photocatalysts but also broadens the application scope of MOF-based photocatalysts.
光催化是一种强大且用途广泛的工具，在合成化学领域得到广泛应用。然而，目前使用的大多数光催化剂都是均相催化剂，不可避免地面临诸如产物 - 催化剂分离和可回收性等问题。为应对这一挑战，我们利用一种均相钌光催化剂作为结构导向模板，制备了一系列具有高孔隙率、稳定性和光催化剂负载量的同构光催化剂封装金属有机框架（光催化剂@金属有机框架）。金属有机框架的规则通道可以分散封装的光催化剂，促进底物和产物的传质，并提供出色的底物限制效应，从而显著提高催化活性以及对有价值有机反应的优异可回收性。例如，金属有机框架光催化剂能够以高收率和出色的对映选择性（高达99% ee）催化酮的不对称曼尼希反应，优于已报道的光催化剂。值得注意的是，这是首例基于金属有机框架的非均相光催化剂在室温及可见光下无需助催化剂就能催化不对称曼尼希反应的情况。这项工作不仅探索了一种制备非均相光催化剂的途径，还拓宽了基于金属有机框架的光催化剂的应用范围。
