Synthesis and crystal structure of zirconium complexes with fluorinated tetradentate beta-ketoiminate ligands

Two ?-ketoiminato complexes of zirconium, di[bis-trifluoroacetylacetone-ethylenediiminato]zirconium Zr(enTFA2)2 (1), and di[bis-trifluoroacetylacetone-trimethylenediiminato]zirconium, Zr(trimenTFA2)2 (2), have been obtained in high yield from the reaction of ZrCl4 and the sodium salt of the corresponding Schiff base. The compounds have been characterized by elemental analysis, NMR, mass spectrometry and X-ray structure determination. The coordination geometry around the zirconium atom is a dodecahedron in 1 and a square antiprism in 2. The increase of the aliphatic bridging chain of the ligand does not produce significant changes in the Zr-Oav bond distances [2.101(2) in 1 and 2.086(4) Å in 2] while the Zr-Nav. bond distances are lengthened [2.432(4) in 1 and 2.491(5) Å in 2].