Visible-Light-Controlled Ruthenium-Catalyzed Olefin Metathesis

Abstract

Olefin metathesis is now one of the most efficient ways to create new carbon-carbon bonds. While most efforts focused on the development of ever-more efficient catalysts, a particular attention has recently been devoted to developing latent metathesis catalysts, inactive species that need an external stimulus to become active. This furnishes an increased control over the reaction which is crucial for applications in materials science. Here, we report our work on the development of a new system to achieve visible-light-controlled metathesis by merging olefin metathesis and photoredox catalysis. The combination of a ruthenium metathesis catalyst bearing two N-heterocyclic carbenes with an oxidizing pyrylium photocatalyst affords excellent and spatial resolution using only visible light as stimulus. Applications of this system in synthesis, as well as in polymer patterning and photolithography with spatially-resolved ROMP, are described.

Photoinitiated ring‐opening metathesis polymerization

“…We presume that this is due to the limited lifetimes of the catalytically active intermediates. Behavior of this sort has recently been reported for redox activated ruthenium catalysts when irradiated in the presence of certain oxidizing pyrylium photocatalysts …”

“…Behavior of this sort has recently been reported for redox activated ruthenium catalysts when irradiated in the presence of certain oxidizing pyrylium photocatalysts. 13 Nanoimprint lithography (NIL) is a process that is capable of transferring nanometer-sized patterns to various substrates. 14 Compared to other lithography techniques, NIL does not require complex light sources or materials that are tailored to specific wavelengths.…”

Designing with Light: Advanced 2D, 3D, and 4D Materials

“…Temporal control has also been demonstrated under UV light to deactivate active catalysts or activate latent species to produce positive and negative pattern respectively. The controlling wavelength was recently extended into the visible region by Rovis and co‐workers who employed a strongly oxidizing pyrilium photocatalyst to activate a latent ruthenium complex …”

Photocontrolled Synthesis of n‐Type Conjugated Polymers

“…Photopolymerizations offer the opportunity for spatiotemporal control and selective catalyst activation by different wavelengths of light . For non‐conjugated polymers, researchers have developed a range of photocontrolled polymerizations . To date, there have been few examples of photopolymerizations to produce CPs .…”

“…[19][20][21] Forn on-conjugated polymers,r esearchers have developed ar ange of photocontrolled polymerizations. [22][23][24][25] To date,there have been few examples of photopolymerizations to produce CPs. [26][27][28][29][30][31][32][33] The existing methods rely on strongly oxidizing conditions and produce largely insoluble p-type (carbazole and thiophene) polymers ( Figure 1c).…”