X-Ray structures of ethylenebis(tetrahydroindenyl)-titanium and -zirconium dichlorides: a revision

The structures of both ethylenebis(η5tetrahydroindenyl)titanium dichloride (1) and its zirconium analog 2 have been redetermined in the centric space group I2/c (non-standard setting of C2/c) at room temperature. Arguments are presented that suggest that the original space group (Cc) in the published X-ray structures of compounds 1 and 2 was incorrectly selected. An improved modification to the literature route that allows the preparation of multi-gram amounts of 1 and 2 is also described.