Zubi Yasmine S, Liu Bingqing, Gu Yifan, Sahoo Dipankar, Lewis Jared C
Department of Chemistry, Indiana University Bloomington Indiana 47405 USA
Department of Chemistry, University of Chicago Chicago IL 60637 USA.
Chem Sci. 2022 Jan 10;13(5):1459-1468. doi: 10.1039/d1sc05792h. eCollection 2022 Feb 2.
Visible light photocatalysis enables a broad range of organic transformations that proceed single electron or energy transfer. Metal polypyridyl complexes are among the most commonly employed visible light photocatalysts. The photophysical properties of these complexes have been extensively studied and can be tuned by modifying the substituents on the pyridine ligands. On the other hand, ligand modifications that enable substrate binding to control reaction selectivity remain rare. Given the exquisite control that enzymes exert over electron and energy transfer processes in nature, we envisioned that artificial metalloenzymes (ArMs) created by incorporating Ru(ii) polypyridyl complexes into a suitable protein scaffold could provide a means to control photocatalyst properties. This study describes approaches to create covalent and non-covalent ArMs from a variety of Ru(ii) polypyridyl cofactors and a prolyl oligopeptidase scaffold. A panel of ArMs with enhanced photophysical properties were engineered, and the nature of the scaffold/cofactor interactions in these systems was investigated. These ArMs provided higher yields and rates than Ru(Bpy) for the reductive cyclization of dienones and the [2 + 2] photocycloaddition between -cinnamoyl imidazole and 4-methoxystyrene, suggesting that protein scaffolds could provide a means to improve the efficiency of visible light photocatalysts.
可见光光催化能够实现一系列通过单电子或能量转移进行的有机转化反应。金属多吡啶配合物是最常用的可见光光催化剂之一。这些配合物的光物理性质已得到广泛研究，并且可以通过修饰吡啶配体上的取代基来进行调节。另一方面，能够实现底物结合以控制反应选择性的配体修饰仍然很少见。鉴于酶在自然界中对电子和能量转移过程具有精确的控制能力，我们设想将钌（II）多吡啶配合物纳入合适的蛋白质支架中构建的人工金属酶（ArMs）可以提供一种控制光催化剂性质的方法。本研究描述了从多种钌（II）多吡啶辅因子和脯氨酰寡肽酶支架构建共价和非共价ArMs的方法。设计了一组具有增强光物理性质的ArMs，并研究了这些体系中支架/辅因子相互作用的性质。对于二烯酮的还原环化反应以及α-肉桂酰咪唑与4-甲氧基苯乙烯之间的[2 + 2]光环加成反应，这些ArMs比Ru（Bpy）具有更高的产率和反应速率，这表明蛋白质支架可以提供一种提高可见光光催化剂效率的方法。
