Amine-functionalised hexagonal mesoporous silica as support for copper(II) acetylacetonate catalyst

• Type: Article in International Scientific Journal
• Date: 2006

Authors

Silva, AR (Author) REIT; Wilson, K (Author) Other; Whitwood, AC (Author) Other; Clark, JH (Author) Other; Freire, C (Author) FCUP

Journal

Title: European Journal of Inorganic Chemistry

Vol. 2006

Pages: 1275-1283

ISSN: 1434-1948

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 46 Citations

Scopus - 40 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-004-MQ6

DOI: 10.1002/ejic.200500979

Abstract (EN): Copper(ii) acetylacetonate was anchored onto a hexagonal mesoporous silica (HMS) material using a two-step procedure: (i) functionalisation of the surface hydroxy groups with (3-aminopropyl)triethoxysilane (AMPTSi) and then (ii) anchoring of the copper(ii) complex through Schiff condensation with free amine groups, using two different metal complex loadings. Upon the first step, nitrogen elemental analysis, XPS and DRIFT showed the presence of amine groups on the surface of the HMS material, and porosimetry indicated that the structure of the mesoporous material remained unchanged, although a slight decrease in surface area was observed. Atomic absorption, XPS and DRIFT showed that copper(ii) acetylacetonate was anchored onto the amine-functionalised HMS by Schiff condensation between the free amine groups and the carbonyl groups of the copper(ii) complex; using EPR an NO3 coordination sphere was proposed for the anchored copper(ii) complex. The new [Cu(acac)(2)]-AMPTSi/HMS materials were tested in the aziridination of styrene at room temperature, using PhI=NTs as nitrogen source and acetonitrile as solvent. The styrene conversion and total TON of the heterogeneous phase reaction are higher than those of the same reaction catalysed in homogeneous phase by [Cu(acac)(2)]; nevertheless, the initial activity decreases and the reaction time increases due to substrate and product diffusion limitations. The heterogeneous catalyst showed a successive slight decrease in catalytic activity when reused for two more times. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9