Al³⁺ Dopants Induced Mg²⁺ Vacancies Stabilizing Single-Atom Cu Catalyst for Efficient Free-Radical Hydrophosphinylation of Alkenes

Abstract

Utilizing heterogeneous catalysts to overcome obstacles for homogeneous reactions is fascinating but very challenging owing to the difficult fabrication of such catalysts based on the character of target reactions. Herein, we report a Al 3+ doping strategy to construct single-atom Cu on MgO nanosheets (Cu 1 /MgO(Al)) for boosting the free-radical hydrophosphinylation of alkenes. Al 3+ dopants in MgO bring about abundant Mg 2+ vacancies for stabilizing dense independent Cu atoms (6.3 wt %), while aggregated Cu nanoparticles are formed without Al 3+ dopants (Cu/MgO). Cu 1 /MgO(Al) exhibits preeminent activity and durability in the hydrophosphinylation of various alkenes with great anti-Markovnikov selectivity (99%). The turnover frequency (TOF) value reaches up to 1272 h −1 , exceeding those of Cu/MgO by ∼6-fold and of traditional homogeneous catalysts drastically. Further experimental and theoretical studies disclose that the prominent performance of Cu 1 /MgO(Al) derives from the accelerated initiating step of phosphinoyl radical triggered by individual Cu atoms.

Active Pd Catalyst for the Selective Synthesis of Methylated Amines with Methanol

“…This indicated that the active metal Pd and Al species were highly S2), further confirming the formation of the Zn vacancies. 25 Furthermore, Al 3+ doping can induce Zn 2+ vacancies in ZnO, which reduces the electron density of Zn and O due to charge neutrality (Figure 4d). 25,38 Clearly, the Pd 3d 5/2 spectrum showed that the active metal existed in the form of Pd 2+ and was slightly shifted to a higher binding energy for 0.4% Pd/Zn(Al)O (10:1) (Figure 4e), possibly due to the metal−support interaction between the Pd and Pd/Zn(Al)O resulting from the metal vacancies.…”

Bimetallic ruthenium–rhodium particles supported on carbon nanotubes for the hydrophosphinylation of alkenes and alkynes

“…Most of these processes require high catalyst loadings along with thermal activation and/or toxic additives. 7–9 In addition, the above-mentioned homogeneous systems do not allow for the recovery of the catalysts, which can be costly especially when dealing with noble metals. In an effort to circumvent this shortcoming, heterogeneous systems have been developed by others more recently but again, elevated temperatures and/or high catalyst loadings are often required for an effective reaction to occur.…”

“…The addition of secondary phosphine oxides to alkenes and alkynes represents a simple and straightforward approach to simultaneously create C–P and C–H bonds, with full atom economy. 4 The various hydrophosphinylation strategies that have been implemented so far include radical processes, 5 photo-activation, 6 and metal-catalyzed reactions 7 as described in seminal reports by Tanaka and co-workers. 8 However, most metal-catalyzed approaches rely on homogeneous metal complexes which are virtually impossible to recycle.…”

Subnanometric Pt clusters supported on MgO-incorporated porous carbon as efficient metal–base bifunctional catalysts for reductive heterocyclization reactions

“…1a), which could be indexed to the (220) and (200) facets of the crystalline MgO (PDF #45-0946), respectively. 41 No diffraction peak ascribed to the metal Pt phase was detected, implying that the Pt species were highly distributed within the skeleton of MgO@C or their loadings are very low. Thermogravimetric analysis (TGA) revealed that MgO@C has thermal stability up to 600 K (Fig.…”