Dendritic fibrous nanosilica-supported dendritic IL/Ru(ii) as photocatalysts for the dicarbofunctionalization of styrenes with carbon dioxide and amines

Abstract

The effectual utilization of heterogeneous catalysts from nano sources through chemical moderation for the α-aminomethylcarboxylation of alkenes with carbon dioxide and amines is an attractive area to study. Dendritic fibrous nanosilica (DFNS) is a cost-effective, resistant, plenteous, and reproducible source with dandelion-like fibrous anatomy. The present paper is a report on an easy method to provide a family of new DFNS-supported dendritic imidazolium IL/Ru(II) heterogeneous catalysts DFNS/IL/Ru (1–3) with high ionic density from DFNS. A positive dendritic effect was perceived in the chemical stabilization performance of CO₂. DFNS/IL/Ru(II) was appropriately identified by UV-vis spectroscopy, XPS, SEM, TEM, FT-IR spectroscopy, and TGA. It was discovered that DFNS/IL/Ru(II) has high catalytic activity for the synthesis of quinoline-2-one through the annulation of ortho-heteroaryl anilines and CO₂. DFNS/IL/Ru (3) could be reutilized ten continuous times with no notable reduction in the catalytic activity. Notably, the coveted quinoline-2-one was prepared on a multi-gram scale by deploying DFNS/IL/Ru (3) as a green heterogeneous catalyst. Owing to the attendance of the zwitterionic liquid functional groups on the exterior layer of the bio-based DFNS/IL/Ru (3) catalyst, DFNS/IL/Ru (3) expressed the highest catalytic activity. This approach provides highly functional γ-amino acids in proper yields with great selective power. This paper announces the first nanocatalyst for this transformation, comprising the DFNS-supported Ru N-heterocyclic carbine complex.