Aminozirconocenes: A new class of zirconocenes with a nitrogen atom directly bonded to an eta(5)-cyclopentadienyl(indenyl) ligand

The reactions of 2-indanone or 3,4-diphenylcyclopent-2-enone with pyrrolidine and N,N'-dimethylethylenediamine respectively lead to the corresponding 2-aminoindenes and 1-amino-3,4-diphenylcyclopentadienes, whose lithium salts can be reacted with ZrCl4 to generate the corresponding moisture-sensitive aminozirconocene dichlorides. The X-ray crystal structure of di-(2-N-pyrrolidine-eta(5)-indenyl)zirconium dichloride was determined, in which the zirconocene exists exclusively as a racemic-mixture, whereas the meso-rotamer is not present. The (indenyl)carbon-nitrogen bond lengths range from 132.5(7) to 134.9(8) pm, which is indicative of considerable multiple bond character.