Self-Assembled Poly(imidazole-palladium): Highly Active, Reusable Catalyst at Parts per Million to Parts per Billion Levels

Abstract

Metalloenzymes are essential proteins with vital activity that promote high-efficiency enzymatic reactions. To ensure catalytic activity, stability, and reusability for safe, nontoxic, sustainable chemistry, and green organic synthesis, it is important to develop metalloenzyme-inspired polymer-supported metal catalysts. Here, we present a highly active, reusable, self-assembled catalyst of poly(imidazole-acrylamide) and palladium species inspired by metalloenzymes and apply our convolution methodology to the preparation of polymeric metal catalysts. Thus, a metalloenzyme-inspired polymeric imidazole Pd catalyst (MEPI-Pd) was readily prepared by the coordinative convolution of (NH(4))(2)PdCl(4) and poly[(N-vinylimidazole)-co-(N-isopropylacrylamide)(5)] in a methanol-water solution at 80 °C for 30 min. SEM observation revealed that MEPI-Pd has a globular-aggregated, self-assembled structure. TEM observation and XPS and EDX analyses indicated that PdCl(2) and Pd(0) nanoparticles were uniformly dispersed in MEPI-Pd. MEPI-Pd was utilized for the allylic arylation/alkenylation/vinylation of allylic esters and carbonates with aryl/alkenylboronic acids, vinylboronic acid esters, and tetraaryl borates. Even 0.8-40 mol ppm Pd of MEPI-Pd efficiently promoted allylic arylation/alkenylation/vinylation in alcohol and/or water with a catalytic turnover number (TON) of 20,000-1,250,000. Furthermore, MEPI-Pd efficiently promoted the Suzuki-Miyaura reaction of a variety of inactivated aryl chlorides as well as aryl bromides and iodides in water with a TON of up to 3,570,000. MEPI-Pd was reused for the allylic arylation and Suzuki-Miyaura reaction of an aryl chloride without loss of catalytic activity.

The oxamate route, a versatile post-functionalization for metal incorporation in MIL-101(Cr): Catalytic applications of Cu, Pd, and Au

“…Both, metallic (335.6 and 340.9 eV binding energies) and cationic Pd species are observed (336.8 and 342 eV binding energies) [20,57,58].…”

Development of Batch and Flow Immobilized Catalytic Systems with High Catalytic Activity and Reusability

“…33) Since nickel belongs to the group 10 elements, I envisioned that some insoluble self-assembled catalysts of polymeric imidazole amphiphiles and the group 10 element metals should provide high catalytic activity with much higher reusability to produce metallopro- Herein, I introduce the development of a novel metalloprotein-inspired polymeric imidazole palladium catalyst, MPPI-Pd. [34][35][36] MPPI-Pd was applied to the allylic arylation/ alkenylation/vinylation of allylic esters and carbonates with aryl/alkenylboronic acids, vinylboronic acid esters, and tetraaryl borates. Even amounts as small as 0.8-40 mol ppm Pd (0.00008-0.004 mol% Pd) of MPPI-Pd efficiently promoted the allylic arylation/alkenylation/vinylation in alcohol and/or water with a catalytic turnover number (TON) of 20000-1250000.…”

Palladium supported on Halloysite-triazolium salts as catalyst for ligand free Suzuki cross-coupling in water under microwave irradiation

“…In this regard, palladium complexes or nanoparticles have been immobilized on various supports such as silica, alumina, zeolites, organic polymers, magnetic nanoparticles and dendrimers [1][2][3][4][5][6][7][8].…”