Dye-Binding Metal-Organic Cage for Highly Efficient Multiphoton Activation of C(sp 3)-H Bonds

Enzymes facilitate chemical conversionsthrough the integratedactivity of multicomponents, but the aggregation of multiactive siteswith molecular containers to emulate enzymatic conversion remainschallenging. Herein, we report a new Ce-III-based octahedralcage with chloride ligands that boosts C(sp (3))-H photoactivation by marrying a Ce-IV -Cl photocatalyst and photoredox catalyst tointegrate photoinduced electron transfer (PET), ligand-to-metal chargetransfer (LMCT), and hydrogen-atom transfer (HAT) events through multiphotonexcitation. This molecular cage binds 2-chloro-9H-thioxanthen-9-one (TXO) for boosting PET via a pseudointramolecularpathway to oxidize Ce-III -Cl to Ce-IV -Cl and form TXO & BULL;-. The LMCT excitation of Ce-IV -Cl istriggered to form Cl-& BULL; that activates C(sp (3))-H via HAT, resultingin the regeneration of Ce-III -Cl andthe formation of an alkyl radical. TXO & BULL;- reducesthe reaction intermediate, which transforms C(sp (3))-H and facilitates recovery of TXOfor subsequent recycling. This approach offers a feasible strategyfor creating highly electrophilic radicals resembling enzymes anddemonstrates their potential for C(sp (3))-H functionalization.