A heterogeneous iridium single-atom-site catalyst for highly regioselective carbenoid O–H bond insertion

Abstract

Transition metal-catalyzed carbenoid insertion of hydroxyl groups represents a robust and versatile method to forge C-O bonds. Achieving site-selective functionalization of alcohols using this transformation has undoubted synthetic value, but remains challenging. Here we report a strategy exploitng an engineered heterogeneous iridium single atom (Ir-SA) catalyst for selective carbenoid O-H insertion, thus providing opportunities in merging material science and catalysis for organic transformations. This catalytic protocol delivers excellent selectivities (up to 99:1) for functionalization of aliphatic over phenolic O-H bonds, even in cases where the analogous homogeneous catalyst, Ir(ttp)COCl, provided modest preferences. DFT calculations suggest that the site-selectivity derives from the lower oxidation state of iridium metal center in the heterogeneous catalyst and its impact on the absorption energies of catalytic species. These results comprise an example of a heterogeneous single atom catalyst providing superior site-selectivity and provide a complementary strategy to address challenges in catalysis for organic synthesis.

Transforming CO2 into Methanol with N-Heterocyclic Carbene-Stabilized Coinage Metal Hydrides Immobilized in a Metal–Organic Framework UiO-68

“…By synergizing the advantages of high activity in homogeneous catalysis and excellent recyclability in heterogeneous catalysis, single-site heterogeneous catalysts have emerged as a class of advanced materials for many industrially important catalytic processes. − In the past several years, particularly, metal–organic frameworks (MOFs) have been exploited as salient platforms to produce single-site heterogeneous catalysts by introducing isolated catalytically active sites into the frameworks. , This is because crystalline porous MOFs possess well-defined structures and excellent designability and tunability in their inorganic building units and organic linkers. A number of attempts have explored single-site MOF catalysts for CO 2 hydrogenation. − Through density functional theory (DFT) calculations, Maihom et al.…”

Iridium‐based electrocatalysts toward sustainable energy conversion

“…With the development of nanotechnology in recent years, the preparation and functionalization of Ir‐based nanomaterials have made significant progress. As an important branch, the electrocatalytic reactions of Ir‐based electrocatalysts including electrocatalytic oxidation reactions and electrocatalytic reduction reactions are quite significant to the basic research and practical utilization 3 …”

“…As an important branch, the electrocatalytic reactions of Ir-based electrocatalysts including electrocatalytic oxidation reactions and electrocatalytic reduction reactions are quite significant to the basic research and practical utilization. 3 The performances of Ir-based electrocatalysts are closely relevant to their structure features (such as morphology, size, and composition), which are also extremely influenced by their synthetic procedures. 4,5 Toward enhanced electrocatalytic behaviors, engineering the Ircontaining materials to nano/atomic scale is widely adopted by researchers because such morphologies can provide enhanced atomic utilization with more active sites.…”

Hollow microstructural regulation of single-atom catalysts for optimized electrocatalytic performance

“…A large number of reviews have focused on the influence of geometric and electronic structure regulations on the catalytic performances of SACs [38,[71][72][73][74][75][76][77] . In contrast, relatively few reviews have discussed the relationship between SACs supported by hollow microstructures and catalytic activity.…”