Urea-Functionalized Self-Assembled Molecular Prism for Heterogeneous Catalysis in Water

Howlader, Prodip and Das, Paramita and Zangrando, Ennio and Mukherjee, Partha Sarathi (2016) Urea-Functionalized Self-Assembled Molecular Prism for Heterogeneous Catalysis in Water. In: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 138 (5). pp. 1668-1676.

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Abstract

Reaction of a ditopic urea ``strut'' (L-1) with cis-(tmen)Pd(NO3)(2) yielded a 3+3] self-assembled molecular triangle (T)L-1 = 1,4-di(4-pyridylureido)benzene; tmen = N,N,N',N'-tetrame-thylethane-1,2-diamine]. Replacing cis-(tmen)Pd(NO3)(2) in the above reaction with an equimolar mixture of Pd(NO3)(2) and a clip-type donor (L-2) yielded a template-free multicomponent 3D trigonal prism (P) decorated with multiple urea moieties L-2 = 3,3'-(1H-1,2,4-triazole-3,5-diyl)dipyridine]. This prism (P) was characterized by NMR. spectroscopy, and the structure was confirmed by X-ray crystallography. The P was employed as an effective hydrogen-bond-donor catalyst for Michael reactions of a series of water-insoluble nitro-olefins in an aqueous medium. The P showed better catalytic activity compared to the urea based ligand L-1 and the triangle T. Moreover, the confined nanospace of P in addition to large product outlet windows makes this 3D architecture a perfect molecular vessel to catalyze Diels-Alder reactions of 9-hydroxymethylanthracene with N-substituted maleimide in the aqueous medium. The present results demonstrate new observations on catalytic aqueous Diels-Alder and Michael reactions in heterogeneous fashion employing a discrete 3D architecture of Pd(II). The prism was recycled by simple filtration and reused several tithes without significant loss of activity.

Item Type:	Journal Article
Publication:	JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copy right for this article belongs to the AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	02 Apr 2016 11:25
Last Modified:	02 Apr 2016 11:25
URI:	http://eprints.iisc.ac.in/id/eprint/53472

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