A novel transition metal compound represented by the formula ##STR1## (wherein each of A.sup.1, A.sup.2, A.sup.3 and A.sup.4 is a cyclopentadienyl group, an indenyl group, a fluorenyl group or their derivative; A.sup.5 is a hydrocarbondiylidene group having 4 to 30 carbon atoms; a pair of A.sup.1 and A.sup.2 as well as a pair of A.sup.3 and A.sup.4 is respectively bonded to the identical carbon atom in A.sup.5 to form a crosslinking structure; each of R.sup.1 and R.sup.2 is a halogen atom, a hydrogen atom, an alkyl group or a silicon-containing alkyl group having 1 to 10 carbon atoms, an aryl group, an alkylaryl group, an arylalkyl group or a halogenated aryl group having 6 to 20 carbon atoms; R.sup.1 and R.sup.2 may be identical or different; each of M.sup.1 and M.sup.2 is titanium, zirconium or hafnium; and M.sup.1 and M.sup.2 may be mutually identical or different), and a method for polymerizing an olefin in the presence of this compound and a co-catalyst. The employment of the combination of the above-mentioned compound and another known transition metal compound as the transition metal compounds permits preparing a polyolefin having a wide molecular weight distribution.
一种由以下式表示的新型过渡
金属化合物:##STR1##(其中A.sup.1、A.sup.2、A.sup.3和A.sup.4中的每一个都是
环戊二烯基、
茚基、
芴基或它们的衍
生物;A.sup.5是具有4至30个碳原子的烃基亚烷基基团;一对A.sup.1和A.sup.2以及一对A.sup.3和A.sup.4分别与A.sup.5中的相同碳原子成键,形成交联结构;R.sup.1和R.sup.2中的每一个都是卤素原子、氢原子、烷基或具有1至10个碳原子的含
硅烷基、芳基、烷基芳基、芳基烷基或具有6至20个碳原子的卤代芳基;R.sup.1和R.sup.2可以相同也可以不同;M.sup.1和M.sup.2中的每一个都是
钛、
锆或
铪;M.sup.1和M.sup.2可以相同也可以不同),以及在该化合物和辅助催化剂的存在下聚合烯烃的方法。使用上述化合物和另一种已知的过渡
金属化合物的组合,可以制备具有宽分子量分布的聚烯烃。