Sk. Manirul Islam

Suzuki–Miyaura reaction by heterogeneously supported Pd in water: recent studies

This review summarizes the progress made essentially in the last fifteen years in the Suzuki–Miyaura coupling reaction by heterogeneous palladium catalysis in water as the sole solvent. The discussion focuses on the heterogenization of the palladium catalyst, efficiency and reusability of the heterogeneous catalysts as well as on the reaction conditions from a sustainable chemistry point of view.

Synthesis of silver–graphene nanocomposite and its catalytic application for the one-pot three-component coupling reaction and one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles in water

A graphene based composite with silver nanoparticles has been synthesized via a simple chemical route and its catalytic activity has been tested for multi-component reactions and click reaction in a one-pot approach. This silver–graphene nanocomposite shows excellent catalytic activity at room temperature for three-component couplings between aldehydes, alkynes and amines (A3-coupling) and one-pot synthesis of 1,4-disubstituted 1,2,3-triazole via click reaction between in situ generated azides (derived from anilines or amines) and terminal acetylenes. This solid silver–graphene catalyst has been characterized by TEM, Raman, XRD and UV-Visible absorption spectra. The developed catalyst is air-stable, inexpensive, easy to prepare and can be facilely recovered and reused five times without significant decrease in activity and selectivity.

Enhanced catalytic performance by copper nanoparticle–graphene based composite

A graphene based composite with copper nanoparticles (Cu–G) has been synthesized and used as catalyst for N-arylation and O-arylation. The structure and composition of the nanocomposite have been characterized by TEM, AFM, Raman and XPS. The catalytic activity of the Cu–G has been tested for the N-arylation of N–H heterocycles using arylboronic acids and the O-arylation of phenols using aryl halides. The catalytic N-arylation produces N-aryl heterocyles and the catalytic O-arylation produces diaryl ethers, under mild reaction conditions with excellent yields and selectivities. The developed catalyst is air-stable, inexpensive, easy to prepare, easy to recover by simple filtration and can be reused without appreciable loss of activity.

Polymer anchored Cu(II) complex: an efficient and recyclable catalytic system for the one-pot synthesis of 1,4-disubstituted 1,2,3-triazoles starting from anilines in water

An efficient procedure for the one-pot synthesis of 1,4-disubstituted 1,2,3-triazole derivatives has been developed by the ‘click’ reaction of azides generated in situ from anilines or amines and terminal acetylenes catalyzed by the polymer anchored Cu(II) catalyst in water without using any additives. The polymer anchored Cu(II) catalyst was synthesized and its catalytic activity was evaluated in the Huisgen [3 + 2] cycloaddition reaction for the first time. This protocol offers several advantages like low catalyst loading, high yields, clean reaction, recyclability of the catalyst, reaction in water, no use of hazardous organic solvents for the purification of product, and one-pot synthesis of triazoles from anilines or amines.

Cu-grafted mesoporous organic polymer: a new recyclable nanocatalyst for multi-component, N-arylation and S-arylation reactions

A new mesoporous Cu-MPTA-1 nanocatalyst has been synthesized via a simple and facile in situ radical polymerization of triallylamine in the presence of an organic–organic self-assembly of anionic surfactant SDS, followed by grafting of Cu(II) at room temperature under an inert atmosphere. This nanomaterial has been characterized by elemental analysis, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV–vis diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA), N2 adsorption–desorption studies, X-ray photoelectron spectroscopy (XPS) and EPR spectroscopy. Cu-MPTA-1 acts as an efficient heterogeneous nanocatalyst exhibiting a high catalytic activity for N-arylation and S-arylation reactions using water as a green solvent and also exhibits an excellent catalytic activity for the one-pot synthesis of propargylamines via a three component coupling of an alkyne, an amine and an aldehyde at room temperature. Moreover, the catalyst is easily recoverable and can be reused six times without an appreciable loss of catalytic activity in the three component coupling reaction. The highly dispersed Cu(II) sites in the Cu-grafted mesoporous polymer could be responsible for the observed high activities of the Cu-MPTA-1 catalyst in the coupling reactions. No evidence of leached Cu from the catalyst during the course of the reaction has been observed, suggesting true heterogeneity in the catalytic process.

Mesoporous poly-melamine-formaldehyde stabilized palladium nanoparticle (Pd@mPMF) catalyzed mono and double carbonylation of aryl halides with amines

A new mesoporous poly-melamine-formaldehyde material supported Pd nano catalyst (mPMF–Pd0) has been synthesized and characterized by thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflection spectroscopy (DRS), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and a N2 adsorption study. The mPMF–Pd0 material showed very good catalytic activity in the field of mono and double amino carbonylation of aryl bromides/iodides. Moreover, the catalyst is easily recoverable and can be reused six times without appreciable loss of catalytic activity in the above reactions. So, the highly dispersed and strongly bound palladium(0) sites in the mPMF–Pd0 could be responsible for the observed high activities. Due to strong binding with the functional groups of the polymer, no evidence of leached Pd from the catalyst during the course of reaction occurred, suggesting true heterogeneity in the catalytic process.

Ag-grafted covalent imine network material for one-pot three-component coupling and hydration of nitriles to amides in aqueous medium

A nitrogen rich porous covalent imine network material (CIN-1) has been successfully employed for grafting silver nanoparticles (Ag NPs). The Ag NPs grafted CIN-1, Ag-CIN-1 has been characterized by elemental analysis, powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (DRS), thermogravimetric analysis (TGA) and EPR spectroscopic studies. Ag-CIN-1 acts as a truly heterogeneous catalyst in the hydration of nitriles to amides and the A3 coupling reactions between the alkyne, amine and aldehyde to produce propargylamines by using water as a green solvent.

Chromium(VI) grafted mesoporous polyaniline as a reusable heterogeneous catalyst for oxidation reactions in aqueous medium

A new Cr(VI)-grafted mesoporous polyaniline material (Cr-MPANI) has been prepared via simple and facile in situ radical polymerization of aniline followed by reaction with potassium dichromate. This material has been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectroscopy (DRS) and Thermogravimetric analysis (TGA). Powder XRD and TEM studies suggested the presence of mesophase and disordered wormhole-like mesopores in this sample. Cr-MPANI acts as a very efficient catalyst for the liquid phase oxidation of alkenes, alkanes and aromatic alcohols using 30% H2O2 as oxidant in water. Oxidation reactions were carried out under very mild conditions, and the desired products were obtained with very high selectivity and relatively high yields. Cr-MPANI can be recycled more than five times without an appreciable loss in activity for its respective catalytic reactions.

A highly active recyclable gold–graphene nanocomposite material for oxidative esterification and Suzuki cross-coupling reactions in green pathway

A graphene based composite with gold nanoparticles has been synthesized via a simple chemical route and the structure and compositions of nanocomposite has been characterized. The catalyst was found to be remarkably stable and active for the oxidative esterification of alcohols under present reaction conditions using molecular oxygen as green oxidant and Suzuki cross-coupling reactions between aryl halides and phenylboronic acids using environmentally friendly water as solvent. The versatility of both the protocols was demonstrated by taking a number of substrates. This protocol offers several advantages like high yields, clean reactions, recyclability of the catalyst, reaction in water and use of green oxidant. This study suggests graphene, as an economical substitute for carbon nanotubes, could act as a prominent support in heterogeneous catalysis.

An aerobic oxidative synthesis of aryl nitriles and primary aryl amides from benzylic alcohols catalyzed by a polymer supported Cu(II) complex

A new polymer supported Cu(II) complex has been synthesized and characterized. The catalytic performance of the complex has been tested for the direct conversion of benzylic alcohols to aryl nitriles. In this reaction ammonium formate was used as the nitrogen source and O2 as the oxidant. Furthermore, the copper-catalyzed one-pot synthesis of primary aryl amides from alcohols was also achieved. The effects of solvents, reaction time and catalyst amount for the aryl nitriles and aryl amides synthesis were reported. This catalyst showed excellent catalytic activity and recyclability. The polymer supported Cu(II) catalyst could be easily recovered by filtration and reused more than five times without appreciable loss of its initial activity.