The reaction occurring between bis(eta5-C5H5)ZrCl2 (C5H5 = cyclopentadienyl) and methylalumoxane (MAO) has been studied by means of electron paramagnetic resonance (EPR) spectroscopy at different zirconium concentrations and Al/Zr mole ratios. The toluene solution of bis(eta5-C5H5)ZrCl2/methylalumoxane, in the absence of ethylene, was verified to be more stable than the catalytic system based on bis(eta5-C5H5)TiCl2/AlR3 (R = alkyl). Zr(IV) was reduced to Zr(III) in small amounts with a Lande factor g = 1,998 and a hyperfine interaction splitting constant alpha (Zr-91) = 7 G. The presence of ethylene strongly increased the efficiency of the Zr(IV) to Zr(III) reduction. Simultaneously it modified the chemical electronic surrounding of the Zr nucleus as revealed by the sharp increase of a (Zr-91) = 12 G.

Reduction of(eta5-cyclonentadienyl)zirconium dichloride in the presence of methylalumoxane

MALDOTTI, Andrea
1994

Abstract

The reaction occurring between bis(eta5-C5H5)ZrCl2 (C5H5 = cyclopentadienyl) and methylalumoxane (MAO) has been studied by means of electron paramagnetic resonance (EPR) spectroscopy at different zirconium concentrations and Al/Zr mole ratios. The toluene solution of bis(eta5-C5H5)ZrCl2/methylalumoxane, in the absence of ethylene, was verified to be more stable than the catalytic system based on bis(eta5-C5H5)TiCl2/AlR3 (R = alkyl). Zr(IV) was reduced to Zr(III) in small amounts with a Lande factor g = 1,998 and a hyperfine interaction splitting constant alpha (Zr-91) = 7 G. The presence of ethylene strongly increased the efficiency of the Zr(IV) to Zr(III) reduction. Simultaneously it modified the chemical electronic surrounding of the Zr nucleus as revealed by the sharp increase of a (Zr-91) = 12 G.
C., Cam; F., Sartori; Maldotti, Andrea
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/1683329
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 25
  • ???jsp.display-item.citation.isi??? ND
social impact