Reaction Chemistry of Zirconocene(II) with Ferrocenyl Carbonyls^§

Abstract Treatment of {Zr}( η 2 ‐Me 3 SiC≡CSiMe 3 )(py) ({Zr}=Zr( η 5 ‐C 5 H 5 ) 2 ; py=C 5 H 5 N) ( 1 ) with FcC(O)H (Fc=Fe( η 5 ‐C 5 H 5 )( η 5 ‐C 5 H 4 )) ( 2 a ) gives dimeric [{Zr}( η 2 ‐OCHFc)] 2 ( 3 ), while the reaction of 1 with ketone FcC(O)Ph ( 2 b ) produces monomeric metallaoxiran [{Zr}( η 2 ‐OCPhFc)(Ph)] ( 4 ). In contrast, compound 1 forms [{Zr}(O=CFc 2 ) 2 ] ( 5 ) in presence of FcC(O)Fc ( 2 c ). The structures of 3 – 5 in the solid state were determined by single crystal X‐ray analysis. In 3 two {Zr}( η 2 ‐OCHFc) building blocks are connected to each other over oxygen bridges with the aldehydes being η 2 ‐coordinated. By exchanging aldehyde 2 a by ketone 2 b , monomeric 4 is accessible with a σ ‐bonded phenylate ligand and a ketone bonded in a η 2 ‐fashion to Zr(IV). In contrast, within 5 two Fc 2 C=O ketones are datively bonded to a zirconocene unit with Zr in the oxidation state II, demonstrating a new family of compounds in which metallocene ketones are coordinated to a group 4 metal. Further, compounds 3 – 5 were characterized by IR spectroscopy and 3 , 4 were investigated by matrix assisted laser desorption/ionization mass spectrometry. In case of 5 , its crystallisation was tracked by NMR spectroscopy and its reaction towards CH 2 Cl 2 was investigated by high resolution mass spectrometry.