SYNTHESIS AND CRYSTAL-STRUCTURE OF ZIRCONIUM COMPLEXES WITH FLUORINATED TETRADENTATE BETA-KETOIMINATE LIGANDS

Two beta-ketoiminato complexes of zirconium, i[bis-trifluoroacetylacet one-ethylenediiminato]zir conium Zr(enTFA(2))(2) (1), and di uoroacety lacetone-trimethylenediiminato]zirconium, Zr(trimenTFA(2))(2) (2), hav e been obtained in high yield from the reaction of ZrCl4 and the sodiu m salt of the corresponding Schiff base. The compounds have been chara cterized by elemental analysis, NMR, mass spectrometry and X-ray struc ture determination. The coordination geometry around the zirconium ato m is a dodecahedron in 1 and a square antiprism in 2. The increase of the aliphatic bridging chain of the ligand does not produce significan t changes in the Zr-O-av bond distances [2.101(2) in 1 and 2.086(4) An gstrom in 2] while the Zr-N-av. bond distances are lengthened [2.432(4 ) in 1 and 2.491(5) Angstrom in 2]. Copyright (C) 1997 Elsevier Scienc e Ltd.