Metal–Organic Layers Hierarchically Integrate Three Synergistic Active Sites for Tandem Catalysis

Abstract We report the design of a bifunctional metal–organic layer (MOL), Hf 12 ‐Ru‐Co, composed of Ru(DBB)(bpy) 2 2+ DBB‐Ru, DBB=4,4′‐di(4‐benzoato)‐2,2′‐bipyridine; bpy=2,2′‐bipyridine connecting ligand as a photosensitizer and Co(dmgH) 2 (PPA)Cl (PPA‐Co, dmgH=dimethylglyoxime; PPA=4‐pyridinepropionic acid) on the Hf 12 secondary building unit (SBU) as a hydrogen‐transfer catalyst. Hf 12 ‐Ru‐Co efficiently catalyzed acceptorless dehydrogenation of indolines and tetrahydroquinolines to afford indoles and quinolones. We extended this strategy to prepare Hf 12 ‐Ru‐Co‐OTf MOL with a Ru(DBB)(bpy) 2 2+ photosensitizer and Hf 12 SBU capped with triflate as strong Lewis acids and PPA‐Co as a hydrogen transfer catalyst. With three synergistic active sites, Hf 12 ‐Ru‐Co‐OTf competently catalyzed dehydrogenative tandem transformations of indolines with alkenes or aldehydes to afford 3‐alkylindoles and bisindolylmethanes with turnover numbers of up to 500 and 460, respectively, illustrating the potential use of MOLs in constructing novel multifunctional heterogeneous catalysts.