Reduction of bis(η5‐cyclopentadienyl)zirconium dichloride in the presence of methylalumoxane
Reduction of bis(η5‐cyclopentadienyl)zirconium dichloride in the presence of methylalumoxane
复制标题
甲基铝氧烷存在下双(η5-环戊二烯基)二氯化锆的还原
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
A. Maldotti
中科院分区：
文献类型：
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作者：
D. Cam;F. Sartori;A. Maldotti
用电子顺磁共振（EPR）研究了在不同锆浓度和Al/Zr摩尔比下，双（η5-C5H5）ZrCl2 （C5H5 =环戊二烯基）与甲基铝氧烷（MAO）的反应。在没有乙烯的情况下，双（η5-C5H5）ZrCl2/甲基铝氧烷甲苯溶液比双（η5-C5H5）TiCl2/AIR3 （R =烷基）的催化体系更稳定。Zr（IV）少量还原为Zr(III)，朗德因子g = 1998，超精细相互作用分裂常数α (91Zr) = 7 g。乙烯的存在大大提高了Zr（IV）还原为Zr（III）的效率。α(91Zr) = 12 G的急剧增加表明它同时改变了Zr原子核的化学电子环。
The reaction occurring between bis(η5-C5H5)ZrCl2 (C5H5 = cyclopentadienyl) and methylalumoxane (MAO) has been studied by means of electron paramagnetic resonance (EPR) spectroscopy at different zirconium concentrations and Al/Zr mole ratios. The toluene solution of bis(η5-C5H5)ZrCl2/methylalumoxane, in the absence of ethylene, was verified to be more stable than the catalytic system based on bis(η5-C5H5)TiCl2/AIR3 (R = alkyl). Zr(IV) was reduced to Zr(III) in small amounts with a Lande factor g = 1,998 and a hyperfine interaction splitting constant α (91Zr) = 7 G. The presence of ethylene strongly increased the efficiency of the Zr(IV) to Zr(III) reduction. Simultaneously it modified the chemical electronic surrounding of the Zr nucleus as revealed by the sharp increase of α(91Zr) = 12 G.