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Covalently anchored organic carboxylic acid on porous silica nano particle: A novel organometallic catalyst (PSNP-CA) for the chromatography-free highly product selective synthesis of tetrasubstituted imidazoles

Paper ID Volume ID Publish Year Pages File Format Full-Text
40455 45854 2013 13 PDF Available
Title
Covalently anchored organic carboxylic acid on porous silica nano particle: A novel organometallic catalyst (PSNP-CA) for the chromatography-free highly product selective synthesis of tetrasubstituted imidazoles
Abstract

•Organic template synthesis of porous silica nanoparticle.•Grafting of COOH functionalized organosilane on silica nanoparticle.•Selective synthesis of tetrasubstituted imidazoles.

A novel organometallic catalyst (PSNP-CA) has been prepared by post synthesis grafting of COOH functionalized organosilane on porous silica nano particle by using surface hydroxyl groups as anchor point. It was characterized by using an array of sophisticated analytical techniques like 13C CP MAS NMR, 29Si MAS NMR, CHN analysis, BET, HR TEM, XRD, TGA, FTIR and pH measurement. The leaching of the active site is greatly avoided as the organic moieties are covalently attached to the inorganic support. This is the first example of organocatalysis promoted by a COOH functionalized porous silica nano particle for the chemoselective synthesis of densely substituted imidazoles. The molecular scaffolds which assimilate bio-active imidazole moiety may be worthwhile molecule from the biological point of view. All the other reported procedures led to the mixture of tri and tetra substituted imidazoles and their proportions were successfully evaluated from crude 1H NMR spectra. Greenness of the process was well instituted as water was exploited as reaction medium. This catalyst retained its activity after having it exposed to ambient atmosphere for 10 days. There was no deteriorating effect of aerial oxygen or moisture towards the activity of the catalyst.

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Keywords
Organometallic catalyst; Post synthesis grafting; Porous nanoparticle; Product selective; Imidazole
First Page Preview
Covalently anchored organic carboxylic acid on porous silica nano particle: A novel organometallic catalyst (PSNP-CA) for the chromatography-free highly product selective synthesis of tetrasubstituted imidazoles
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 458, 10 May 2013, Pages 183–195
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis