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Titolo:
SCANNING AND ENERGY-DISPERSIVE EXAFS STUDIES OF NICKEL ALKENE OLIGOMERIZATION CATALYSTS
Autore:
CORKER JM; DENT AJ; EVANS J; HAGELSTEIN M; KAMBHAMPATI VL;
Indirizzi:
UNIV SOUTHAMPTON,DEPT CHEM SOUTHAMPTON SO17 1BJ HANTS ENGLAND SERC,DARESBURY LAB WARRINGTON WA4 4AD CHESHIRE ENGLAND EUROPEAN SYNCHROTRON RADIAT FACIL F-38043 GRENOBLE FRANCE
Titolo Testata:
Journal de physique. IV
fascicolo: C2, volume: 7, anno: 1997,
parte:, 2
pagine: 879 - 881
SICI:
1155-4339(1997)7:C2<879:SAEESO>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
CURVED-WAVE THEORY; DIMERIZATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
6
Recensione:
Indirizzi per estratti:
Citazione:
J.M. Corker et al., "SCANNING AND ENERGY-DISPERSIVE EXAFS STUDIES OF NICKEL ALKENE OLIGOMERIZATION CATALYSTS", Journal de physique. IV, 7(C2), 1997, pp. 879-881

Abstract

In situ EDE and scanning EXAFS studies of homogeneous alkene oligomerisation catalysts are reported. EDE spectra were acquired either on Station 9.3 at the SRS Daresbury Laboratory using a bent Si(220) crystalmonochromator (Ni and Br K-edges) or on ID24 at the ESRF using a Si(lll) monochromator in a Bragg geometry (Ni K-edge). The catalysts studied were derived from mixtures of Ni(acac)(2) (acac = 2,4-pentanedionato) and AlEt2(OEt) or NiX2(PEt3)(2) (X = Cl, Br) and AlEt3. For Ni(acac)(2)/AlEt2(OEt), Ni K-edge EDE is consistent with a mean structure similar in nature to trimeric Ni(acac)(2) but with partial substitution of acac ligands by alkene and alkyl groups. At 25 degrees C, further breakdown of the trimer occurs to give alkylated monomeric nickel species. For NiCl2(PEt3)(2)/AlEt3, low temperature Ni K-edge EDE has been used to monitor alkylation of the Ni centre, and for ambient temperaturemixtures of NiBr2(PEt3)(2)/AlEt3, Br K-edge EDE data shows complete loss of Br from the metal centre occurring within minutes of adding AlEt3. Instrumental difficulties (detector and beamline setup)at the current time prevent acquisition of analysable EXAFS in a timescale fasterthan 0.1-10 s for these types of systems.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/09/20 alle ore 00:09:22