Chen Jian-Rui, Zhou Dongling, Liu Yungen, Li Mian, Xiao Yonghong, Huang Xiao-Chun, Che Chi-Ming
Chemistry and Chemical Engineering Guangdong Laboratory Shantou Guangdong P. R. China
Department of Chemistry, State Key Laboratory of Synthetic Chemistry, The University of Hong Kong Pokfulam Road Hong Kong P. R. China
Chem Sci. 2024 Dec 23;16(5):2202-2214. doi: 10.1039/d4sc06058j. eCollection 2025 Jan 29.
Phosphorescent gold(iii) complexes possess long-lived emissive excited states, making them ideal for use as molecular sensors and photosensitizers for organic transformations. Literature reports indicate that gold(iii) emitters exhibit good catalytic activity in homogeneous photochemical reactions. Heterogeneous metal-organic framework (MOF)-supported gold(iii) photocatalysts are considered to show high recyclability in photochemical reactions and potentially provide new selectivities. Here, we report the design and development of visible-light-absorbing MOF-covalently linked gold(iii) photocatalysts. A MOF-supported gold(iii) complex exhibits a longer phosphorescence lifetime than its homogeneous counterpart, reaching approximately 110 μs under argon and 12 μs under air when suspended in acetonitrile. This is attributed to the localization of the gold(iii) complex within the MOF nano-cages. The MOF-derived gold(iii) photosensitizer exhibits good catalytic performance in intramolecular and intermolecular [2 + 2] cycloaddition reactions to construct functionalized cyclobutanes and azetidines, both of which are important building blocks for pharmaceuticals. These photochemical [2 + 2] cycloaddition reactions catalyzed by the gold(iii)-MOF are governed by an energy transfer mechanism and do not require redox modulators. Under similar reaction conditions, the crossed [2 + 2] photocycloaddition reaction of two activated alkenes proceeds smoothly, and the cyclobutane product is obtained within 3 hours of irradiation under dilute conditions (0.2 mol dm of alkene).
磷光金（III）配合物具有长寿命的发射激发态，使其成为用于有机转化的分子传感器和光敏剂的理想选择。文献报道表明，金（III）发射体在均相光化学反应中表现出良好的催化活性。非均相金属有机框架（MOF）负载的金（III）光催化剂被认为在光化学反应中具有高可回收性，并可能提供新的选择性。在此，我们报告了可见光吸收型MOF共价连接的金（III）光催化剂的设计与开发。一种MOF负载的金（III）配合物的磷光寿命比其均相对应物更长，当悬浮在乙腈中时，在氩气下约为110 μs，在空气中约为12 μs。这归因于金（III）配合物在MOF纳米笼中的定位。MOF衍生的金（III）光敏剂在分子内和分子间[2 + 2]环加成反应中表现出良好的催化性能，以构建功能化的环丁烷和氮杂环丁烷，这两者都是药物的重要构建块。这些由金（III）-MOF催化的光化学[2 + 2]环加成反应受能量转移机制控制，不需要氧化还原调节剂。在类似的反应条件下，两种活化烯烃的交叉[2 + 2]光环加成反应顺利进行，在稀释条件下（烯烃浓度为0.2 mol dm）照射3小时内即可得到环丁烷产物。
