Palladium Catalysis for Aerobic Oxidation Systems Using Robust Metal–Organic Framework

Abstract

Described here is a new and viable approach to achieve Pd catalysis for aerobic oxidation systems (AOSs) by circumventing problems associated with both the oxidation and the catalysis through an all‐in‐one strategy, employing a robust metal–organic framework (MOF). The rational assembly of a PdII catalyst, phenanthroline ligand, and CuII species (electron‐transfer mediator) into a MOF facilitates the fast regeneration of the PdII active species, through an enhanced electron transfer from in situ generated Pd0 to CuII, and then CuI to O2, trapped in the framework, thus leading to a 10 times higher turnover number than that of the homogeneous counterpart for Pd‐catalyzed desulfitative oxidative coupling reactions. Moreover, the MOF catalyst can be reused five times without losing activity. This work provides the first exploration of using a MOF as a promising platform for the development of Pd catalysis for AOSs with high efficiency, low catalyst loading, and reusability.

Visible light-driven efficient palladium catalyst turnover in oxidative transformations within confined frameworks

“…2c, there are two N 1s peaks of binding energy (BE) in UiO-67-Ir, signifying two kinds of coordination environment of N atoms. The BE of N 1s peak at 398.8 eV can be ascribed to the N atoms in free bpy ligand, similar to that of UiO-67-bpy 20,46 , while the one located at 400 eV is attributed to the Ir IIIcoordinated N atoms (Supplementary Fig. 13).…”

“…2d and Supplementary Fig. 20), respectively, unambiguously suggesting the inclusion of Pd II salts within the framework 20 . Moreover, for both UiO-67-Ir-Pd(OAc) 2 and UiO-67-Ir-Pd(TFA) 2 , there are three kinds of N 1 s BE peaks located at 398.8, 399.7, 400.2 and 398.9, 399.9, 400.4 eV, respectively (Fig.…”

“…However, the inclusion of excess undesired oxidants gives rise to low atom economy and deleterious organic waste. One alternative approach is the substitution of stoichiometric oxidants to catalytic amount of electron transfer mediators (ETMs) or photocatalyst with O 2 as the terminal oxidant 1,[11][12][13][14][15][16][17][18][19][20] . It serves as a milder manner to complete the Pd reoxidation via stepwise electron transfer between Pd, ETMs, or photocatalyst and O 2 .…”

Metal–Organic Framework-Based Catalysts with Single Metal Sites

“…Such metal site pairs have been achievable on metal nodes and metallolinkers in many MOFs. 45,260,350,351 As for the metal nodes, Zhou's group performed a postsynthetic cooperative cluster metalation for the Zr 339 Copyright 2016 American Chemical Society. (c) Aperture-opening encapsulation of the ruthenium complex ( tBu PNP)Ru(CO)HCl into UiO-66 ( tBu PNP = 2,6-bis((di-tert-butyl-phosphino)methyl)pyridine).…”

Aerobic Heterogeneous Palladium-Catalyzed Oxidative Allenic C−H Arylation: Benzoquinone as a Direct Redox Mediator between O 2 and Pd

“…[33][34][35][36][37][38][39][40][41][42] However, its application in aerobic oxidative cross-coupling reactions still remains elusive. In 2019, Jiang et al 43 developed an elegant heterogeneous Pd-catalyzed aerobic oxidation system (AOS) for desulfitative coupling by assembly of Pd catalyst, phenanthroline ligand, and copper into a robust metal-organic framework (MOF). Recently, our group [44][45][46][47] has immobilized palladium into the cavities of aminopropyl-functionalized siliceous mesocellular foam (Pd-AmP-MCF) for allenic C(sp 3 )-H oxidative reactions.…”