Oxide-Bridged Heterobimetallic Aluminum/Zirconium Catalysts for Ethylene Polymerization
A bimetallic aluminum/zirconium complex Cp*2Zr(Me)OAl(DIPH) [DIPH‐H2 = 3,3′‐bis(2‐methylallyl)‐(1,1′‐biphenyl)‐2,2′‐diol; Cp* = C5Me5] was prepared in good yield by the reaction of (DIPH)AlMe with Cp*2Zr(Me)OH. In contrast to Roesky's catalyst, Cp2Zr(Me)O(Me)Al(DIPP‐nacnac) {DIPP‐nacnac = CH[(C...
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Veröffentlicht in: | European journal of inorganic chemistry 2015-04, Vol.2015 (12), p.2132-2138 |
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Sprache: | eng |
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Zusammenfassung: | A bimetallic aluminum/zirconium complex Cp*2Zr(Me)OAl(DIPH) [DIPH‐H2 = 3,3′‐bis(2‐methylallyl)‐(1,1′‐biphenyl)‐2,2′‐diol; Cp* = C5Me5] was prepared in good yield by the reaction of (DIPH)AlMe with Cp*2Zr(Me)OH. In contrast to Roesky's catalyst, Cp2Zr(Me)O(Me)Al(DIPP‐nacnac) {DIPP‐nacnac = CH[(CMe)(2,6‐iPr2C6H3N)]2}, it contains no Al–Me functionality and has increased Lewis acidity at Al. Crystal structures and the NMR spectra of the aluminum complex (DIPH)AlMe and the bimetallic Al/Zr species reveal in both cases dimeric complexes. The crystal structure of [Cp*2Zr(Me)OAl(DIPH)]2 shows a planar Al2O2 core and a terminal Cp*2Zr(Me)O group. Ethylene polymerization in toluene was studied for the bimetallic complex with a variety of scavengers. Under comparable polymerization conditions, the methylalumoxane‐activated species show high activities that are similar to those obtained with Cp*2ZrCl2 and Roesky's bimetallic complex Cp2Zr(Me)OAl(Me)(DIPP‐nacnac), with a relatively narrow polydispersity index (2.47).
The targeted synthesis of a new bimetallic aluminum/zirconium species with remaining Lewis acidity on aluminum gives a dimeric Al–O–Zr complex. In the presence of methylalumoxane, this μ‐oxo complex is able to activate ethylene to produce polyethylene with high activity. |
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ISSN: | 1434-1948 1099-0682 |
DOI: | 10.1002/ejic.201500123 |