Phosphorus coordinated Rh single-atom sites on nanodiamond as highly regioselective catalyst for hydroformylation of olefins

Abstract

Single-atom Rh catalysts present superior activity relative to homogeneous catalyst in olefins hydroformylation, yet with limited success in regioselectivity control. In the present work, we develop a phosphorus coordinated Rh1 single-atom catalyst with nanodiamond as support. Benefiting from this unique structure, the catalyst exhibits excellent activity and regioselectivity in hydroformylation of arylethylenes with wide substrate generality, i.e., with high conversion (>99%) and high regioselectivity (>90%), which is comparable with the homogeneous counterparts. The coordination interaction between Rh1 and surface phosphorus species is clarified by 31P solid-state NMR and X-ray absorption spectroscopy (XAS). Rh single atoms are firmly anchored over nanodiamond through Rh-P bonds, guaranteeing good stability in the hydroformation of styrene even after six runs. Finally, by using this catalyst, two kinds of pharmaceutical molecules, Ibuprofen and Fendiline, are synthesized efficiently with high yields, demonstrating a new prospect of single-atom catalyst in pharmaceutical synthesis.

Ultralow‐Loading and High‐Performing Ionic Liquid‐Immobilizing Rhodium Single‐Atom Catalysts for Hydroformylation

“…due to high chemical and thermal stability. Especially, Keggin-type heteropolyanions could lost one WO unit to offer vacant Keggin-type anions [XW 11 O 39 ] nÀ (X = P, n = 7; X = Si, n = 8) with significant coordinating ability through tuning pH value. Thus other transition metals can incorporate into the vacant POMs and afford a transition metal (e. g., Co, Ni, Fe, Mn, Ru, Pd, Pt, etc.)…”

“…reported that single‐atom catalyst Rh 1 /ZnO can afford a comparable catalytic activity with that of RhCl(PPh 3 ) 3 in hydroformylation of styrene [8a] . Subsequently, single‐atom Rh catalysts including Rh 1 /CoO, [9] Rh 1 /CeO 2 [10] and Rh 1 /PNP‐ND [11] (nanodiamond‐supported phosphorus‐coordinated Rh 1 ) have also been reported for hydroformylation. These materials consist of the dispersed single metal atoms on a support and can enhance the utilization efficiency [12] of the precious Rh atoms remarkably (Scheme 1C).…”

Comparison of Heterogeneous Hydroformylation of Ethylene and Propylene over RhCo3/MCM-41 Catalysts

“…Olefin hydroformylation is an important process in the industry to produce aldehydes and alcohols. , At present, homogeneous Rh complexes are widely used as catalysts for olefin hydroformylation with high activity and selectivity. , The difficulty of separating the catalysts from the reaction mixture remains a major technical challenge for the application of homogeneous catalysts. , Thus, significant efforts have been devoted to heterogeneous hydroformylation using Rh-based catalysts by anchoring Rh complexes, ,− Rh nanoparticles, − or Rh single atoms − on support materials. However, it is still challenging to improve the heterogeneous catalysts to be as efficient as their homogeneous counterparts for hydroformylation. , A better mechanistic understanding of olefin hydroformylation catalyzed by heterogeneous catalysts is crucial for the rational design of improved catalysts.…”

Homogeneity of Supported Single‐Atom Active Sites Boosting the Selective Catalytic Transformations

“…Atomically dispersed Rh atoms in Rh 1 /PNP‐ND (phosphorus coordinated Rh single atoms supported on nanodiamond) as confirmed by HRTEM, ac‐HAADF‐STEM and CO‐DRIFTs results show excellent catalytic performance for the hydroformylation of arylethylenes with wide substrate generality. [ 409 ] The Rh 1 /PNP‐ND catalyst reaches high conversion (> 99%) towards aldehyde and a high branched/linear aldehyde molar ratio of 13.3:1, which is commensurate with those of the homogeneous counterparts (Figure 21c). XAS and 31 P solid‐state NMR reveal that Rh single atoms are stabilized by the bidentate chelation with two P atoms, contributing to the good stability of six cycles without activity and selectivity decreasing under a controlled conversion of 77%.…”

“…Reproduced with permission. [ 409 ] Copyright 2021, Springer Nature. d) Hydroformylation of styrene to linear aldehydes over Rh 1 /CeO 2 catalyst, which is coupled with the low‐temperature water‐gas shift reaction (LWGS) without the use of ligands.…”