Cage Encapsulated Gold Nanoparticles as Heterogeneous Photocatalyst for Facile and Selective Reduction of Nitroarenes to Azo Compounds

Mondal, Bijnaneswar and Mukherjee, Partha Sarathi (2018) Cage Encapsulated Gold Nanoparticles as Heterogeneous Photocatalyst for Facile and Selective Reduction of Nitroarenes to Azo Compounds. In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 140 (39). pp. 12592-12601.

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Abstract

A discrete nanoscopic organic cage (OC1(R)) has been synthesized from a phenothiazine based trialdehyde treating with chiral 1,2-cyclohexanediamine building block via dynamic imine bond formation followed by reductive amination. The cage compound has been characterized by several spectroscopic methods, which advocate that OC1(R) has trigonal prismatic shape formed via 2 + 3] self-assembled imine condensation followed by imine reduction. This newly designed cage has aromatic walls and porous interior decorated with two cyclic thioether and three vicinal diamine moieties suitable for binding gold ions to engineer the controlled nucleation and stabilization of ultrafine gold nanoparticles (AuNPs). The functionalized confined pocket of the cage has been used for the controlled synthesis of AuNPs with narrow size distribution via encapsulation of Au(III) ions. Inductively coupled plasma mass spectrometric (ICP-MS) analysis revealed that the composite Au@OC1(R) has very high (similar to 68 wt %) gold loading. In distinction, reduction of gold salts in absence of the cage yielded structureless agglomerates. The fine-dispersed cage anchored AuNPs (Au@OC1(R)) have been finally used as potential heterogeneous photocatalyst for very facile and selective conversion of nitroarenes to respective azo compounds at ambient temperature in just 2 h reaction time. Exceptional chemical stability and reusability without any agglomeration of AuNPs even after several cycles of use are the potential features of this material. The composite Au@OC1(R) represents the first example of organic cage supported gold nanoparticles as photocatalyst.

Item Type:	Journal Article
Publication:	JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copy right for this article belong to AMER CHEMICAL SOC
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	31 Oct 2018 13:58
Last Modified:	31 Oct 2018 13:58
URI:	http://eprints.iisc.ac.in/id/eprint/60993

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