Tricoordinate Organochromium(III) Complexes Supported by a Bulky Silylamido Ligand Produce Ultra-High-Molecular Weight Polyethylene in the Absence of Activators - Liu - 2016 - Helvetica Chimica Acta - Wiley Online Library
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Low-coordinate organoCr(III) complexes supported by the silylamido ligand &N(SiMe3)DIPP (DIPP&=&2,6-diisopropylphenyl) are ethylene polymerization catalyst precursors without the need of additional cocatalyst. The reaction of CrCl3(THF)3 with 3 or 2 equiv. of LiN(SiMe3)DIPP yields either a four-membered cyclometalated Cr complex or Cr[N(SiMe3)DIPP]2Cl, respectively, with no trace of Cr[N(SiMe3)DIPP]3. Addition of 1 equiv. of LiN(SiMe3)DIPP to Cr[N(SiMe3)DIPP]2Cl also leads to the four-membered metallacycle, which upon heating transforms to a new six-membered Cr metallacycle, likely via a &-bond metathesis step. Cr[N(SiMe3)DIPP]2Cl can be readily converted to bis(amido)Cr(III) vinyl and alkyl complexes Cr[N(SiMe3)DIPP]2R (R&=&vinyl, Bn, and Me). All of these structurally characterized low-coordinate Cr(III) complexes with a Cr&C bond initiate the polymerization of ethylene in the absence of activators or cocatalysts, producing ultra-high-molecular weight polyethylene.STABILIZATION OF RIGID POLY(VINYLCHLORIDE) PLASTICS WITH BIS-AMIDES AND ULTRAVIOLET ABSORBERS
United States Patent 3496134
Inventors:
Giaimo, Matthew Peter DI.
Application Number:
US3496134DA
Publication Date:
02/17/1970
Filing Date:
06/20/1967
Export Citation:
AMERICAN CYANAMID CO
Primary Class:
Other Classes:
International Classes:
C08K5/20; C08K5/315; (IPC1-7): C08F45/60
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US Patent References:
32446683239478321443631188873079366292104829192592648650
Foreign References:
FR1086182A
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