Palladium catalyst supported on N-aminoguanidine functionalized magnetic graphene oxide as a robust water-tolerant and versatile nanocatalyst

Abstract

A novel heterogeneous Pd catalyst has been developed by decorating palladium onto the surface of Naminoguanidine functionalized magnetic graphene oxide nanosheets (denoted as Pd@AGu-MGO), while the diethylene glycol (DEG) group has been applied as an organic spacer. The usefulness of the Pd@AGu-MGO nanocatalyst was investigated in palladium catalyzed organic reactions including Heck/ Suzuki couplings of aryl halides and reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The nanocatalyst showed high efficiency and thermal stability (up to 300 C). The catalyst recovery test was performed using an external magnet device, and showed that this catalyst can be reused several times without a significant decrease in its performance and catalytic activity. The loading level of Pd in the Pd@AGu-MGO catalyst was assessed as 0.9 mmol g À1 by ICP-AES and elemental analysis. This catalyst is more remarkable from the environmental and economic points of view because of its key properties such as high efficiency and turnover frequency (TOF), mild reaction conditions, utilization of green solvent, simple product work-up, and easy catalyst recovery.

Immobilized Pd on (S)‐methyl histidinate‐modified multi‐walled carbon nanotubes: a powerful and recyclable catalyst for Mizoroki–Heck and Suzuki–Miyaura C–C cross‐coupling reactions in green solvents and under mild conditions

“…All of the products are known and characterized by comparing their physical data such as FT‐IR, 1 H NMR and 13 C NMR spectra with those reported in the literature . The obtained results are comparable to or even higher than conversion yields compared to a reported amino palladium complex immobilized on a carbon surface …”

“…However, the preparation of most reported ligands seems rather laborious and time‐consuming. Therefore, employing available biomolecules such as amino acids, alkaloids and nucleic acids and supporting them on solid substrates is highly favorable . Among them, histidine is an applicable amino acid in catalytic systems, its key features including air‐stability, low cost, nontoxicity and easy accessibility (via chemical synthesis) that make it a more efficient ligand or nanometal species stabilizer for practical applications compared with other well‐established ligands …”

Carbon‐Derived Supports for Palladium Nanoparticles as Catalysts for Carbon‐Carbon Bonds Formation

“…Several groups have reported several types of Pd/Fe 3 O 4 NPs on GO as easily recoverable magnetic materials. As in the case of MWCNTs, metformin (Met) has been used to support Pd NPs on magnetic GO by Shafiee and co‐workers . By a co‐precipitation method Fe 3 O 4 NPs were deposited in then surface of GO, which was further modified by the N ‐aminoguanidine Met using diethylene glycol (DEG) giving MGO‐Met.…”

“…As in the case of MWCNTs, [77] metformin (Met) has been used to support Pd NPs on magnetic GO by Shafiee and co-workers. [135] By a coprecipitation method Fe 3 O 4 NPs were deposited in then surface of GO, which was further modified by the N-aminoguanidine Met using diethylene glycol (DEG) giving MGO-Met. The resulting material was used for the stabilization and immobilization of Pd@ Fe 3 O 4 -GO-Met.…”

Mo (CO)6‐assisted Pd‐supported magnetic graphene oxide‐catalyzed carbonylation‐cyclization as an efficient way for the synthesis of 4(3H)‐quinazolinones

“…We have had several efforts on the synthesis of novel quinazolinone derivatives and extending novel methodologies for the synthesis of these compounds, as well as several projects on the transition metal‐catalyzed reactions . Due to the pharmacological significance of 4(3 H )‐quinazolinones and the chemical importance of CO generation and carbonylation reaction on one hand, and the efficiency of palladium catalyst on the other hand, we wish to report a new method for the efficient synthesis of 4(3 H )‐quinazolinones via the palladium‐catalyzed carbonylation‐cyclization of N ‐(2‐bromoaryl) benzimidamides by molybdenum hexacarbonyl.…”