Synthesis, Structure, and Polymerization Behavior of Novel Azulenyl Metallocenes Producing Propylene-Ethylene Pseudo-Copolymer

Abstract

Novel bridged bis-azulenyl metallocenes bearing substituents at the 2-, 4-, and 8-positions, dichlorodimethylsilylenebis(2-methyl-4-phenyl-8-n-butyl-8H-azulenyl)hafnium and dichlorodimethylsilylenebis(2-methyl-4,8-diphenyl-8H-azulenyl)hafnium, were synthesized. The structure of the former compound was determined by X-ray crystallographic analysis to have C 2 symmetry. When activated with methylaluminoxane (MAO), both compounds gave an active propylene polymerization catalyst. In propylene homopolymerization, propylene-ethylene pseudo-copolymer was obtained unexpectedly. Although the metallocene has C 2 symmetry, the obtained polypropylene was elastomeric and showed no melting point on measurement by differential scanning calorimetry (DSC). The 13C NMR analysis of the polymer showed the presence of a large amount of regioinversion.

Reaction of the heteronuclear cluster RuOs3(μ-H)2(CO)13 with azulenes

“…In 5a, the angle between the planes defined by the fivemembered ring and C(5)eC(9)eC(6)eC(8) is 136.2 , while the angle between C(7) and the C(5)eC(9)eC(6)eC(8) plane is 165.1 ; these angles are 132.7 and 169.9 , respectively, in 5b. This nonplanarity is very similar to that observed in an azulenyl hafnium complex that has been reported [39]. The azulenyl ligand is bonded to the cluster via a novel m 3 ,h 5 :s 2 mode; the organic moiety caps Ru(5) in a h 5 -cyclopentadienyl manner, and C(2) is also asymmetrically bound to Os(1) and Ru(4).…”

ansa-Metallocenes Bearing 4-(N-Azolyl)-2-methylindenyl and Related Ligands: Development of Highly Isoselective Catalysts for Propene Polymerization at Higher Temperatures

“…The structural changes in the Me 2 Si-bridged bis­(inden-1-yl) ligand framework were extensively performed and studied, including replacement of the C6 ring in indenyl moieties with a five-membered heterocycle and a nonaromatic hydrogenated C6 or C7 ring, variation of the substitution at positions 2, 4, ,,,, 5, 6 ,,,,, and 7, ,,, and introduction of heteroatomic substituents. ,,,,, The last modification applied to the constrained-geometry complexes was previously shown to give ethylene-1-octene copolymerization catalysts of high thermal stability, which is desirable for multiple reasons. High-temperature solution polymerization processes allow for increased throughput, decreased energy necessary for devolatization, and decreased fouling, resulting in simplification of the treatment following polymer production to separate and recover the medium from the polymer product and thus decreasing its cost .…”

Dihydroguaiazulenide Complexes and Catalysts of Group 8–12 Transition Metals: Ligands from Renewable Feedstock Replace, even Outmatch Petrochemical Based Cyclopentadienyl Chemistry

“…They were explored as olefin polymerization catalysts. [19,19,21,21] The mixture of many catalyst isomers limits their applicability. A neutral Gua ligand complex of type [Rh(Gua)(cod)]BF 4 was reported to act as catalyst at 2 mol % load in the insertion of dimethyl acetylenedicarboxylate into the 5-membered ring of Gua forming heptalene-1,2-dicarboxylate.…”

“…[18] Sugano et al used a carbolithiation approach in their design of -SiMe 2 -bridged ansa-metallocenes from PhLi and 2-methyl azulenes. [16,[19][20][21] To the best of our knowledge, no further reports on organometallic chemistry of AzuH or GuaH, no XRD characterization of any AzuH and GuaH complexes, and no explicit NMR spectroscopic proof for the isolation of only one isomer of AzuH or GuaH complexes has been published up to date.…”