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Phosphine‐ligated transition metal complexes play a pivotal role in modern catalysis, but our understanding of the impact of ligand counts on the catalysis performance of the metal center is limited. Here we report the synthesis of a low‐coordinate mono(phosphine)‐Rh catalyst on a metal‐organic layer (MOL), P‐MOL • Rh, and its applications in the hydrogenation of mono‐, di‐, and tri‐substituted alkenes as well as aryl nitriles with turnover numbers (TONs) of up to 390000. Mechanistic investigations and density functional theory calculations revealed the lowering of reaction energy barriers by the low steric hindrance of site‐isolated mono(phosphine)‐Rh sites on the MOL to provide superior catalytic activity over homogeneous Rh catalysts. The MOL also prevents catalyst deactivation to enable recycle and reuse of P‐MOL • Rh in catalytic hydrogenation reactions.

Phosphine‐ligated transition metal complexes play a pivotal role in modern catalysis, but our understanding of the impact of ligand counts on the catalysis performance of the metal center is limited. Here we report the synthesis of a low‐coordinate mono(phosphine)‐Rh catalyst on a metal‐organic layer (MOL), P‐MOL • Rh, and its applications in the hydrogenation of mono‐, di‐, and tri‐substituted alkenes as well as aryl nitriles with turnover numbers (TONs) of up to 390000. Mechanistic investigations and density functional theory calculations revealed the lowering of reaction energy barriers by the low steric hindrance of site‐isolated mono(phosphine)‐Rh sites on the MOL to provide superior catalytic activity over homogeneous Rh catalysts. The MOL also prevents catalyst deactivation to enable recycle and reuse of P‐MOL • Rh in catalytic hydrogenation reactions.

Covalent organic frameworks (COFs) have received broad interest owing to their permanent porosity, high stability, and tunable functionalities. COFs with long‐range π‐conjugation and photosensitizing building blocks have been explored for sustainable photocatalysis. Herein, we report the first example of COF‐based energy transfer Ni catalysis. A pyrene‐based COF with sp²carbon‐conjugation was synthesized and used to coordinate Ni^IIcenters through bipyridine moieties. Under light irradiation, enhanced energy transfer in the COF facilitated the excitation of Ni centers to catalyze borylation and trifluoromethylation reactions of aryl halides. The COF showed two orders of magnitude higher efficiency in these reactions than its homogeneous control and could be recovered and reused without significant loss of catalytic activity.

Covalent organic frameworks (COFs) have received broad interest owing to their permanent porosity, high stability, and tunable functionalities. COFs with long‐range π‐conjugation and photosensitizing building blocks have been explored for sustainable photocatalysis. Herein, we report the first example of COF‐based energy transfer Ni catalysis. A pyrene‐based COF with sp²carbon‐conjugation was synthesized and used to coordinate Ni^IIcenters through bipyridine moieties. Under light irradiation, enhanced energy transfer in the COF facilitated the excitation of Ni centers to catalyze borylation and trifluoromethylation reactions of aryl halides. The COF showed two orders of magnitude higher efficiency in these reactions than its homogeneous control and could be recovered and reused without significant loss of catalytic activity.

We report the design of a bifunctional metal–organic layer (MOL), Hf₁₂‐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 Hf₁₂secondary building unit (SBU) as a hydrogen‐transfer catalyst. Hf₁₂‐Ru‐Co efficiently catalyzed acceptorless dehydrogenation of indolines and tetrahydroquinolines to afford indoles and quinolones. We extended this strategy to prepare Hf₁₂‐Ru‐Co‐OTf MOL with a [Ru(DBB)(bpy)₂]²⁺photosensitizer and Hf₁₂SBU capped with triflate as strong Lewis acids and PPA‐Co as a hydrogen transfer catalyst. With three synergistic active sites, Hf₁₂‐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.

We report the design of a bifunctional metal–organic layer (MOL), Hf₁₂‐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 Hf₁₂secondary building unit (SBU) as a hydrogen‐transfer catalyst. Hf₁₂‐Ru‐Co efficiently catalyzed acceptorless dehydrogenation of indolines and tetrahydroquinolines to afford indoles and quinolones. We extended this strategy to prepare Hf₁₂‐Ru‐Co‐OTf MOL with a [Ru(DBB)(bpy)₂]²⁺photosensitizer and Hf₁₂SBU capped with triflate as strong Lewis acids and PPA‐Co as a hydrogen transfer catalyst. With three synergistic active sites, Hf₁₂‐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.

Metal–organic frameworks (MOFs) have been extensively used for single‐site catalysis and light harvesting, but their application in multicomponent photocatalysis is unexplored. We report here the successful incorporation of an Ir^IIIphotoredox catalyst and a Ni^IIcross‐coupling catalyst into a stable Zr₁₂MOF, Zr₁₂‐Ir‐Ni, to efficiently catalyze C−S bond formation between various aryl iodides and thiols. The proximity of the Ir^IIIand Ni^IIcatalytic components to each other (ca. 0.6 nm) in Zr₁₂‐Ir‐Ni greatly facilitates electron and thiol radical transfers from Ir to Ni centers to reach a turnover number of 38 500, an order of magnitude higher than that of its homogeneous counterpart. This work highlights the opportunity in merging photoredox and organometallic catalysts in MOFs to effect challenging organic transformations.