Bis-Cycloruthenated Complexes in Visible Light-Induced C-H Alkylation with Epoxides

Area of Science:

• Organometallic Chemistry
• Photochemistry
• Catalysis

Background:

• Bis-cycloruthenated complexes (BCRCs) of the type [Ru(N^C)2L2] are crucial intermediates in Ru(II)-catalyzed directed C-H functionalization of arenes.
• The ground-state reactivity of BCRCs with electrophiles is well-documented, but their behavior upon photoexcitation remains unexplored.

Purpose of the Study:

• To investigate the photoexcitation of BCRCs and their potential to access chemically useful excited states.
• To explore the reactivity of photoexcited BCRCs in electron transfer processes for alkyl halide activation.
• To expand the scope of Ru-catalyzed C-H functionalization to include novel transformations.

Main Methods:

• Photoexcitation studies of bis-cycloruthenated complexes (BCRCs).
• Investigation of electron transfer processes for alkyl halide activation.
• Application of photoexcited BCRCs in C-H functionalization reactions.

Main Results:

• Photoexcitation of BCRCs successfully accesses chemically relevant excited states.
• Photoexcited BCRCs exhibit significantly enhanced reactivity in electron transfer processes compared to their ground states.
• This enhanced reactivity overcomes limitations in ground-state ruthenium-catalyzed C-H functionalization.

Conclusions:

• Photoexcited BCRCs offer a new avenue for activating alkyl halides via electron transfer.
• The study expands the chemical space of Ru-catalyzed C-H functionalization, notably enabling ortho-alkylation with epoxides.
• This work highlights the potential of photochemistry to unlock novel reactivity in organometallic catalysis.