samarocene 、 反-2-戊烯 以
neat (no solvent) 为溶剂,
以1%的产率得到[(C5Me5)2Sm]2(μ-O)
参考文献:
名称:
Metalation as a Termination Step in Polymerization Reactions Involving α-Olefins and Ethylene As Detected by Field Desorption Mass Spectrometry1
摘要:
Field desorption mass spectroscopy (FD-MS) in conjunction with NMR spectroscopy has been used to study how olefins larger than ethylene are incorporated into polyethylene using (C(5)Me(5))(2)Sm-based catalysts under hydrogen. Polymerization reactions of propene, 1-pentene, cis- and trans-2-pentene, 1-heptene, trans-2-heptene, trans-3-heptene, 1-octene, and 1-nonadecene with ethylene under H-2 and with CD2=CD2 under D-2 were studied as well as reactions of ethylene with propene-d(6) and 3,3,3-propene-d(3) using (C(5)Me(5))(2)Sm and (C(5)Me(5))(2)Sm(eta(3)-CH(2)CHCHR) precursors where R = H, Et, and Bu. For the olefins listed above, the combined analytical techniques with the appropriate deuterium labeling indicate that one olefin is selectively incorporated per polyethylene chain and that incorporation occurs by insertion into a Sm-H bond in the system rather than via an allyl group. Metalation of the olefin by growing polymer chains was found to be competitive with hydrogenolysis as a termination step and can be used to control molecular weight. 2-Pentene and 2-heptene do not incorporate as readily as their alpha-olefin analogs and 3-heptene incorporation was not detectable, but these internal olefins are effective termination agents via metalation.