Preparation, characterization and application of silica-supported palladium complex as a new and heterogeneous catalyst for Suzuki and Sonogashira reactions

Palladium anchored to BisPyP@bilayer-SiO2@NMP organic-inorganic hybrid as an efficient and recoverable novel nanocatalyst in suzuki and stille C-C coupling reactions

The palladium anchored to BisPyP@bilayer-SiO2@NMP organic-inorganic hybrid was employed as an effective and recyclable organometallic catalyst in Suzuki and Stille C-C coupling reactions. The structure of this magnetic nanocatalyst was determined using various techniques such as SEM, TEM, FT-IR, EDS, ICP-OES, VSM, N2 adsorption-desorption isotherms, XRD, and TGA. In both of the mentioned coupling paths, the yields of the products were very favorable and ranged from 90 to 98%. Also, they had significant features compared to previous reports, such as very short reaction time (5-15 and 7-20 min respectively in the Suzuki and Stille reactions), easy work-up, broad substrate scope, ease of separation of the catalyst using a magnet, suitable reproducibility of the catalyst in 6 runs, heterogeneous nature of the catalyst and not washing it during consecutive runs with confirmation of hot filtration and ICP-OES methods.

A novel, efficient and magnetically recyclable Cu-Ni bimetallic alloy nanoparticle as a highly active bifunctional catalyst for Pd-free Sonogashira and C-N cross-coupling reactions: a combined theoretical and experimental study

In this study, a Fe3O4@SiO2@Cyt-Ni/Cu nanocomposite as a novel heterogeneous bimetallic catalyst was synthesized which exhibits efficient performance for the Sonogashira and C-N cross-coupling reactions. The characterization of the catalyst was studied by FT-IR, PXRD, VSM, EDX, TEM, FE-SEM and TGA analyses. The geometry optimization and relative energies of the designed bimetallic complexes were theoretically determined using density functional theory (DFT) calculation at the B3LYP/6-31G**/LANL2DZ level. The catalyst showed good activity in the coupling of various aryl halides with alkynes (Sonogashira reaction) as well as aryl halide with N-heterocycles and achieved coupling products with good to high yields for all of them in a short time. The high catalytic performance could be due to the synergistic effect between Ni and Cu, which causes the reaction to proceed more efficiently. This heterogeneous nanocatalyst could be easily recovered from the reaction mixture with an external magnet and reused for 7 consecutive runs with minimal loss of catalytic activity.

Pd immobilization biguanidine modified Zr-UiO-66 MOF as a reusable heterogeneous catalyst in Suzuki-Miyaura coupling

In recent days, nanohybrid metal organic frameworks (MOF) have been considered as next generation catalysts due to their unique features like large surface to volume ratio, tailorable geometry, uniform pore sizes and homogeneous distribution of active sites. In this report, we address the biguanidine modified 3D Zr-centred MOF UiO-66-NH2 following a post synthetic modification approach. Utilizing the excellent chelating ability of biguanidine, Pd ions are immobilized over the host matrix MOF. The as-synthesized material was physicochemically characterized using a broad range of analytical techniques like FT-IR, electron microscopy, EDS, elemental mapping, XRD and ICP-OES. Subsequently the material has been catalytically employed in the classical Suzuki-Miyaura coupling towards the synthesis of diverse biphenyl derivatives at sustainable conditions. There are very few reports on the covalently modified MOFs towards the organic coupling reactions. The catalyst has been isolated by centrifugation and recycled in 9 consecutive runs with almost insignificant leaching and minute decrease in reactivity.

Immobilizing of palladium on melamine functionalized magnetic chitosan beads: A versatile catalyst for p-nitrophenol reduction and Suzuki reaction in aqueous medium

In this study, an environmental-friendly palladium catalyst with high efficiency, magnetic, recoverability, reusability, and excellent stability was prepared and thoroughly characterized by the Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), X-ray diffraction (XRD), Elemental mapping, Thermogravimetric analysis (TGA) and Energy-dispersive X-ray spectroscopy (EDX). Results demonstrates that melamine provides a coordination point on the surface of chitosan microspheres, which provides a platform for the uniform distribution of palladium (II) and combines with palladium (II) firmly to avoid unnecessary leaching of nanoparticles. Besides, Fe₃O₄/CS-Me@Pd microcapsules exhibited high catalytic performance in reducing p-NP in water at room temperature (150-300 s). This composite was also effective in the Suzuki-Miyaura coupling reaction under mild conditions with high catalytic performance (TON = 3.8 × 10⁴, TOF = 7.6 × 10⁴). Reproducibility experiments also showed that Fe₃O₄/CS-Me@Pd microcapsules have high recovery efficiency and can work at least six times during these two catalytic reactions. The hot filtration test indicated that the catalyst has heterogeneous nature.

Ultrasound assisted synthesis of Pd NPs decorated chitosan-starch functionalized Fe3O4 nanocomposite catalyst towards Suzuki-Miyaura coupling and reduction of 4-nitrophenol

In recent days the nanomagnetic biocomposites have been evolved as sustainable green catalysts. In that context, we are prompted to design and synthesize a novel Pd NP adorned chitosan-starch dual biopolymer encapsulated core-shell type magnetic nanocomposite (Fe₃O₄@CS-Starch/Pd) in an eco-friendly pathway applying ultrasound irradiations. The morphological and physicochemical features of the material were determined using several advanced techniques like FT-IR, FESEM, HRTEM, EDX, atomic mapping, VSM, XRD and ICP-OES. Catalytic efficiency of the material was investigated in the ultrasound assisted classical Suzuki-Miyaura coupling towards the synthesis of diverse range of biaryl derivatives and in the catalytic reduction of 4-Nitrophenol.In both the protocols the catalyst exhibited excellent performances. Sonication had a significant role in enhancing the catalytic performances in both the reactions as compared to conventional heating. Due to super-paramagnetism, the catalyst was easily magnetically isolable and reused in 11 cycles without considerable leaching and change in reactivity.

Fabrication of Pd NPs on pectin-modified Fe3O4 NPs: A magnetically retrievable nanocatalyst for efficient C-C and C-N cross coupling reactions and an investigation of its cardiovascular protective effects

The present report represents the synthesis of a novel Pd NPs immobilized over a natural polysaccharide (pectin) coated Fe₃O₄ magnetic nanocomposite material (Fe₃O₄@pectin/Pd) for investigating the cardiovascular protective effects. The biomolecular functionalization not only stabilizes the ferrite nanoparticles from agglomeration but also provides an environment for the biogenic reduction of Pd²⁺ ions. This protocol is a promising breakthrough for the synthesis of a quasi-heterogeneous catalyst, a bridge between heterogeneous and homogeneous medium. The structure, morphology and physicochemical properties of the material were characterized utilizing various analytical techniques like FT-IR, FE-SEM, TEM, VSM, EDX-elemental mapping, ICP, EDX and XPS. The catalyst showed excellent reactivity in C-C and C-N cross coupling reactions via Suzuki and Buchwald-Hartwig reactions respectively. An array of different biphenyls and aryl amines were then procured by reactions of various aryl halides with phenylboronic acid or secondary amines over the catalyst affording good to excellent yields. The catalyst was easily recoverable using an external magnet and thereafter recycled for several trials with insignificant palladium leaching or loss in catalytic performance. To investigate the cardiovascular protective activities of catalyst, the MTT assay was done on Human Aortic Endothelial Cells (HAEC), Human Coronary Artery Endothelial Cells (HCAEC), and Human Pulmonary Artery Endothelial Cells (HPAEC) cell lines. Nanocatalyst-treated cell cutlers significantly (p ≤ 0.01) decreased the caspase-3 activity, and DNA fragmentation. It raised the cell viability and mitochondrial membrane potential in the high concentration of Mitoxantrone-treated HAEC, HCAEC, and HPAEC cells. According to the above findings, nanocatalyst can be administrated as a cardiovascular protective drug for the treatment of cardiovascular diseases after approving in the clinical trial studies in humans.

One-step hydroxylation of benzene to phenol over Schiff base complexes incorporated onto mesoporous organosilica in the presence of different axial ligands

Liquid-phase hydroxylation of benzene to phenol using Schiff base complexes anchored on a mesoporous organosilica support was investigated in various solvents when molecular oxygen was utilized as a green oxidant.

Palladium nanoparticles decorated into a biguanidine modified-KIT-5 mesoporous structure: a recoverable nanocatalyst for ultrasound-assisted Suzuki–Miyaura cross-coupling

In the current research work, a new KIT-5-biguanidine-Pd(0) catalyst was prepared and applied to ultrasound-assisted Suzuki–Miyaura cross-coupling reactions using ultrasound waves at ambient temperature. The ultrasound-assisted method is a green and efficient method for C–C coupling. Many parameters of the Suzuki coupling reaction were examined, such as the irradiation time, the types of organic and inorganic bases, the types of aprotic and protic solvents, and the dosage (mol%) of catalyst. Also, the results showed that the yields from the ultrasound-assisted coupling reactions were higher than from non-irradiated reactions. The prepared catalyst was characterized via HR-TEM, SEM-EDX-mapping, FT-IR, ICP-AAS, BET-BJH, and XRD studies. The stability and catalytic performance of the prepared catalyst were good, and it could be reused 6 times without catalytic activity loss for the Suzuki–Miyaura cross-coupling reaction.

In the current research work, a new KIT-5-biguanidine-Pd(0) catalyst was prepared and applied to ultrasound-assisted Suzuki–Miyaura cross-coupling reactions using ultrasound waves at ambient temperature.

Cross-linked chitosan with a dicationic ionic liquid as a recyclable biopolymer-supported catalyst for cycloaddition of carbon dioxide with epoxides into cyclic carbonates

A dicationc ionic liquid was synthesized and immobilized on chitosan as a catalyst for cycloaddition of CO₂ with epoxides for synthesis of cyclic carbonates.

Palladium stabilized by 3,4-dihydroxypyridine-functionalized magnetic Fe3O4nanoparticles as a reusable and efficient heterogeneous catalyst for Suzuki reactions

A Pd supported on 3,4-dihydroxypyridine (Py)-functionalized Fe₃O₄(Fe₃O₄/Py/Pd) hybrid material has been synthesized for the first time.

Green synthesis of tetrahydrobenzo[b]pyrans, pyrano[2,3-c]pyrazoles and spiro[indoline-3,4′-pyrano[2,3-c]pyrazoles catalyzed by nano-structured diphosphate in water

Preparation of nanostructured diphosphate Na₂CaP₂O₇. Avoiding of any acid catalysts. The prepared catalyst is reusable and eco-friendly. The method is easy and contains simple experimental procedure.

Heck, Suzuki and Sonogashira cross-coupling reactions using ppm level of SBA-16 supported Pd-complex

SBA-16-supported Pd-complex (100–500 mol ppm) catalyzed the Heck, Suzuki and Sonongashira cross-coupling reactions under mild reaction conditions without a significant loss of its activity.