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711.
C.‐H. Ahn M. Tahara T. Uozumi J. Jin S. Tsubaki T. Sano K. Soga 《Macromolecular rapid communications》2000,21(7):385-389
The polymerization of 2‐butene and its copolymerization with ethylene have been investigated using four kinds of dichlorobis(β‐diketonato)titanium complexes, [ArN(CH2)3NAr]TiCl2 (Ar = 2,6‐iPr2C6H3) and typical metallocene catalysts. The obtained copolymers display lower melting points than those produced of homopolyethylene under the same polymerization conditions. 13C NMR analysis indicates that 9.3 mol‐% of 2‐butene units were incorporated into the polymer chains with Ti(BFA)2Cl2‐MAO as the catalyst system. With the trans‐2‐butene a higher copolymerization rate was observed than with cis‐2‐butene. A highly regioselective catalyst system for propene polymerization, [ArN(CH2)3NAr]TiCl2 complex using a mixture of triisobutylaluminium and Ph3CB(C6F5)4 as cocatalyst, was found to copolymerize a mixture of 1‐butene and trans‐2‐butene with ethylene up to 3.1 mol‐%. Monomer isomerization‐polymerization proceeds with typical metallocene catalysts to produce copolymers consisting of ethylene and 1‐butene. 相似文献
712.
Robin Schulte Dr. Sandra Afflerbach Prof. Dr. Heiko Ihmels 《European journal of organic chemistry》2023,26(5):e202201398
In the search for improved photochromic systems that may be used for the efficient reversible conversion of light into chemical energy, eight monoaryl-substituted norbornadienes are presented, which carry naphthyl, anthracenyl, or donor-acceptor-phenyl substituents to establish an extended π system. The substrates were synthesized by Suzuki-Miyaura coupling reactions, and their absorption properties, the key parameters of the photochromic equilibrium, and the energy storage density of the quadricyclane products were examined. It was observed that these compounds have favorable properties for chemical energy storage. Specifically, 2-(1-naphthyl)norbornadiene showed a pronounced red shift of the absorption, a long half-life (35 d) and a relatively high energy storage density (361 KJ/Kg) of the respective quadricyclane. Therefore, the so far neglected monoaryl-norbornadienes represent a useful and complementary class of compounds that should be considered in the development of efficient molecular solar thermal energy storage (MOST) compounds, which can reversibly convert sunlight into chemical energy. 相似文献