Synthesis of biguanide-functionalized single-walled carbon nanotubes (SWCNTs) hybrid materials to immobilized palladium as new recyclable heterogeneous nanocatalyst for Suzuki–Miyaura coupling reaction

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.

Biguanides: Species with versatile therapeutic applications

Biguanides are compounds in which two guanidine moieties are fused to form a highly conjugated system. Biguanides are highly basic and hence they are available as salts mostly hydrochloride salts, these cationic species have been found to exhibit many therapeutic properties. This review covers the research and development carried out on biguanides and accounts the various therapeutic applications of drugs containing biguanide group-such as antimalarial, antidiabetic, antiviral, anticancer, antibacterial, antifungal, anti-tubercular, antifilarial, anti-HIV, as well as other biological activities. The aim of this review is to compile all the medicinal chemistry applications of this class of compounds so as to pave way for the accelerated efforts in finding the drug action mechanisms associated with this class of compounds. Importance has been given to the organic chemistry of these biguanide derivatives also.

Structural features influencing the activity of bis-biguanide ligands in the Suzuki–Miyaura cross-coupling reaction in neat water

Catalytic reactions play an integral role in the development of green chemistry. Herein, we report new bis-biguanide compounds containing alkyl and aryl spacers as ligands for the Suzuki–Miyaura cross-coupling reaction in water. These ligands show similar catalytic activity to metformin independently of the nature of the spacer between the two biguanide units.

The chemistry of biguanides: from synthetic routes to applications in organic chemistry

In this minireview, we discuss the chemistry of biguanides and their applications in catalysis. We present their super basicity as a consequence of their structure, the most efficient ways to synthesize symmetric and unsymmetric functionalized biguanides, and their applications in organic catalysis as triazine precursors and ligands in organometallic catalysis.

Reducing-agent-free facile preparation of Rh-nanoparticles uniformly anchored on onion-like fullerene for catalytic applications

Herein we report a very simple ‘mix and heat’ synthesis of a very fine Rh-nanoparticle loaded carbon fullerene-C60 nanocatalyst (Rh(0)NPs/Fullerene-C60) for the very first time.

Synthesis and Characterization of Biguanide and Biguanidium Surfactants for Efficient and Recyclable Application in the Suzuki-Miyaura Reaction

We report here the synthesis and thorough characterization of a new family of alkylbiguanides and alkylbiguanidium chlorides by ¹H and ¹³C NMR and X-ray diffraction. Their critical micelle concentration was first determined by surface tension measurements. Hexylbiguanide was then studied as a surfactant in the micellar Suzuki-Miyaura cross-coupling reaction. The unexpected low reactivity of the system at high Pd/hexylbiguanide ratios was due to the change of the size and the shape of the aggregates, observed by transmission electron microscopy. The best catalytic activity was obtained for a 1:1 Pd/hexylbiguanide ratio for which the micellar conditions were conserved. Better results were obtained for several substrates, when compared to those previously obtained with metformin under the same reaction conditions. Higher yields and a better recyclability were obtained under micellar conditions with hexylbiguanide.

CuCl heterogenized on metformine-modified multi walled carbon nanotubes as a recyclable nanocatalyst for Ullmann-type C–O and C–N coupling reactions

Herein, a novel MWCNTs-Met/CuCl nanocatalyst synthesis method by metformine covalent grafting on the surface of carbon nanotubes and subsequent coordination with a CuCl catalyst is described.

Fe3O4/PEG-SO3H as a heterogeneous and magnetically-recyclable nanocatalyst for the oxidation of sulfides to sulfones or sulfoxides

We present below a sulfonated-polyethylene glycol-coated Fe₃O₄ nanocomposite (Fe₃O₄/PEG-SO₃H) as a greatly effective and ecological nanocatalyst for the selective oxidation of sulfides to sulfoxides or sulfones with brilliant yields under solvent-free conditions by employing 30% hydrogen peroxide as the oxidant.

Metformin as a versatile ligand for recyclable palladium-catalyzed cross-coupling reactions in neat water

We present the high catalytic activity of an in situ generated palladium(ii)/metformin complex in neat water for the Suzuki–Miyaura and Sonogashira cross-coupling reactions.

Palladium nanoparticles supported on a carbazole functionalized mesoporous organic polymer: synthesis and their application as efficient catalysts for the Suzuki–Miyaura cross coupling reaction

Pd nanoparticles supported on a carbazole functionalized mesoporous organic polymer exhibit high performance in the Suzuki–Miyaura cross coupling reaction with good catalytic activity, substrate adaptability and recyclability.

Pd nanoparticles deposited on Isoniazid grafted multi walled carbon nanotubes: synthesis, characterization and application for Suzuki reaction in aqueous media

The prepared Isoniazide-MWCNTs were used to deposition of Pd NPs as novel nanocatalyst. The catalyst showed high activity in Suzuki coupling reaction of aryl halides (X = I, Br, Cl).

Palladium NPs supported on novel imino-pyridine-functionalized MWCNTs: efficient and highly reusable catalysts for the Suzuki–Miyaura and Sonogashira coupling reactions

In this article a new heterogeneous nanocatalyst based on palladium supported on functionalized multi-walled carbon nanotubes (MWCNTs) has been introduced.