The propensity of a half-sandwich (η⁵-tetramethylcyclopentadienyl) dimethylsilylamido Ti(IV)-based catalyst bearing an auxiliary diethylboryl-protected pyridyl moiety (Ti-8), activated by methylaluminoxane (MAO) to homopolymerize α-olefins such as ethylene, 1-hexene and styrene as well as to copolymerize styrene with 1,3-cyclo-hexadiene is described. The reactivity of Ti-8 was investigated in comparison to a 6-(2-(diethylboryl)phenyl)pyrid-2-yl-free analogue (Ti-3).
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http://dx.doi.org/10.3390/molecules16010567 | DOI Listing |
Macromol Rapid Commun
November 2024
Department of Pharmaceutical Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama, 939-0398, Japan.
The covalent attachment of poly(ethylene glycol) (PEGylation) to materials minimizes non-specific fouling of the material surface with biocomponents. While the PEGylation reaction on polar surfaces is widely used and regarded as a common technique, the PEGylation on less polar polymers and elastomers is extremely difficult due to the absence of reactive points with PEG terminus. Herein, the design and synthesis of an orthogonal agent with a nitrile N-oxide and a phenyl carbamate that can mediate between an alkene and an amine are reported.
View Article and Find Full Text PDFAdv Sci (Weinh)
October 2024
Lehrstuhl für Anorganische Chemie II - Katalysatordesign, Sustainable Chemistry Centre, University of Bayreuth, 95440, Bayreuth, Germany.
α-Olefins are very important bulk and fine chemicals and their synthesis from ethylene, an abundantly available and inexpensive feedstock, is highly attractive. Unfortunately, the direct or on-purpose synthesis of olefins from ethylene is limited to three examples, 1-butene, 1-hexene, and 1-octene, all having a linear structure. Herein, the direct synthesis of 3-methylenepentane and 4-ethylhex-1-ene, branched trimerization, and tetramerization products of ethylene, respectively, is reported.
View Article and Find Full Text PDFDalton Trans
August 2024
Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China.
Chemistry
October 2024
CPE Lyon, CNRS, UMR 5128, Catalysis, Polymerization, Processes and Materials (CP2M), Université Claude Bernard Lyon 1, 43 Bd du 11 Novembre 1918, 69616, Villeurbanne, France.
Exploring the surface organometallic chemistry on silica of highly electrophilic yttrium complexes is a relatively uncommon endeavor, particularly when focusing on tris-alkyl complexes characterized by Y-C σ-alkyl bonds. A drawback with this class of complexes once grafted on silica, is the frequent occurrence of alkyl transfer by ring opening of siloxane groups, resulting in a mixture of species. Herein, we employed a more stable homoleptic yttrium allyl complex bearing bulky η-1,3-bis(trimethylsilyl)allyl ligand to limit this transfer reaction.
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June 2024
Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226, F-35000 Rennes, France.
The preparation of dizirconium complexes based on a novel bis(indenyl)-(/)-stilbene platform was explored. Negishi coupling between the -generated diorganozincates obtained from the respective //-(/)-dibromostilbenes and the bromo-functionalized zirconocene (η-Cp*)(η-2-methyl-4-bromoindenyl)ZrCl, or, alternatively, the preparation of bis(indene)stilbene pro-ligands {//-(/)-BisIndSB}H through Negishi coupling of the corresponding dibromostilbenes with 4-bromoindene and subsequent metallation/transmetallation with Cp*ZrCl or Zr(NMe), allowed the preparation of a series of dinuclear complexes. These were analyzed by NMR spectroscopy and some of them by iASAP-mass spectrometry and by X-ray diffraction studies.
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