Merging Two Functions in a Single Rh Catalyst System: Bimodular Conjugate for Light-Induced Oxidative Coupling

A single molecular rhodium catalyst
system (PC2-Cp#RhIII) bearing two functional
domains for both photosensitization
and C–H carbometalation was designed to enable an intramolecular
redox process. The hypothesized charge-transfer species (PC2•–-Cp#RhIV) was characterized by spectroscopic
and electrochemical analyses. This photoinduced internal oxidation
allows a facile access to the triplet state of the key post-transmetalation
intermediate that readily undergoes C–C bond-forming reductive
elimination with a lower activation barrier than in its singlet state,
thus enabling catalytic C–H arylation and methylation processes.

一种单一分子钯催化剂体系（PC2-Cp#RhIII）被设计，该体系包含两个功能域，分别用于光敏化和C-H碳金属化，旨在实现分子内氧化还原过程。所假设的电荷转移物种（PC2•–-Cp#RhIV）通过光谱分析和电化学分析进行了表征。这种光诱导的内氧化过程使得便捷地进入关键后金属化中间体的三重态成为可能，该中间体能够以低于其单重态的活化能垒发生C-C键形成的还原消除反应，从而实现催化C-H芳基化和甲基化过程。