From crown ethers to zeolites: Reaction of EtAlCl2 with crown ethers |
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Authors: | Jerry L Atwood Hosny Elgamal Gregory H Robinson Simon G Bott James A Weeks William E Hunter |
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Institution: | (1) Department of Chemistry, University of Alabama, 35486 University, AL, USA |
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Abstract: | In contrast to aluminum alkyls, alkyl aluminum halides such as EtAlCl2 react with crown ethers to form cation-anion pairs which exhibit the liquid clathrate effect. Specifically, 12-C-4·AlCl2]AlCl3Et] and 18-C-6·AlCl2]AlCl3Et] have been isolated and characterized by X-ray diffraction techniques. The cations show aluminum in an octahedral environment made up of four of the oxygen atoms from the crown and two chlorine atoms. The 12-C-4 derivative crystallizes in the monoclinic space group P21/c with cell constants of a=7.497(4), b=22.121(8), c=12.339(5) Å, =94.99(3)o, and Z=4 for =1.43 g cm–3. Least-squares refinement based on 1413 observed reflections led to a final conventional R value of 0.093. The 18-C-6 complex belongs to the triclinic space group P1 with a=8.414(4), b=12.193(6), c=12.394(6) Å, =73.14(4), =86.07(4), =81.52(4)o, and Z=2 for =1.45 g cm–3. Refinement based on 2605 observed reflections led to R=0.063. The complex aluminum-containing species are related to a class of compounds called aluminoxanes. |
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Keywords: | crown ether liquid clathrate aluminum alkyl aluminoxane |
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