Core Cross‐Linked Micelle‐Based Nanoreactors for Efficient Photocatalysis

Stable nanoscale cross‐linked polymer micelles containing Ru complexes (Ru‐CMs) were prepared from monomethoxy[poly(ethylene glycol)]‐ block ‐poly( L ‐lysine) (MPEG‐PLys) and [(bpy) 2 Ru(fmbpy)](PF 6 ) 2 (bpy=bipyridine, fmbpy=5‐formy‐5′‐methyl‐2,2′‐bipyridine). To stabilize the micelles, bifunctional glutaraldehyde was used as a cross‐linker to react with the free amino groups of the PLys block. After that, the Ru‐CMs showed very good stability in common solvents. The Ru‐CMs showed photocatalytic activity and selectivity in the oxidation of sulfides that were as high as those of the well‐known [Ru(bpy) 3 (PF 6 ) 2 ] complex, because the micelles were swollen in the methanol–sulfide mixture. Moreover, because of the nanoscale size of the particles and their high stability, the Ru‐CM photocatalysts can be readily recovered by ultrafiltration and reused without loss of photocatalytic activity. This work highlights the potential of using cross‐linked micelles as a platform for developing highly efficient heterogeneous photocatalysts for a number of important organic transformations.