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.

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The present work introduces the favorable synthesis of porous functionalized nanomaterials with excellent surface area, porosity, and high CO 2 capture ability to facilitate cyclizative reactions by incorporating the CO 2 molecule into highly reactive organic moieties. We have attempted to fulfill the target by the decoration of Ag NPs over the exterior surfaces of covalent organic frameworks (COFs) TpPa-1 and TpTta to achieve Ag@TpPa-1 and Ag@TpTta nanomaterials with an absolutely ordered structure. Characterizations of the nanocatalysts (Ag@TpPa-1 and Ag@ TpTta) have been performed by field emission scanning electron microscopy, thermogravimetric tools, N 2 adsorption/desorption, transmission electron microscopy, Fourier transform infrared spectroscopy, UV−vis, and powder X-ray diffraction analysis. These Ag NPs architectured porous COFs described excellent performance for the benign synthesis of cyclic carbamates from unsaturated amines in the presence of N-iodosuccinimide (NIS) and several 2-oxazolidinone derivatives from propargylamine derivatives via cyclizative atmospheric CO 2 capture under solvent-free and alkali-free conditions (sustainable approach). The microporous material Ag@TpTta revealed most excellent catalytic performance than Ag@TpPa-1during production of cyclic carbamates and oxazolidinones which indicates that the selection of Ag NPs decorated COFs with the excellent surface area has a contributory effect on carboxylative cyclization reaction. Density functional theory studies furnished important information to establish the detailed mechanism of silver (0) catalyzed CO 2 incorporation into unsaturated amine. These COFs enriched with N centers can interact with the Ag NPs at their outer exterior surfaces very tightly. These two nanocatalysts exhibited magnificent recycling efficiencies for the generation of cyclic carbamates and 2-oxazolidinones with almost zero silver leaching from the exterior part of the catalyst.

We have designed a unique strategy to obtain a zinc-salen functionalized porous polymer (Zn@SBMMP) with high zinc content (15.3 wt%) by an easy one-step, cost effective and scalable process, which shows unprecedented catalytic efficiency in the CO2 fixation reaction via cycloaddition of CO2 with epoxides. We hypothesize that a high density of Zn-Schiff base/salen units present in the porous polymer network is responsible for the exceptionally high catalytic performance of Zn@SBMMP.

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