Synthesis of new adducts and co-ordination complexes of zirconium and titanium containing beta-aminoketone ligands. Crystal structures of isostructural adducts MCl4·2Pr(i)HNCMe=CHCMe=O (M = Ti or Zr) and the complex [Zr(PhNCMe=CHCMe=O)(2)Cl-2]

The reaction of MCl 4 (M = Zr or Ti) with β-aminoketones HL (R 1 HNCR 2 =CHCR 3 =O; R 2 = R 3 = Me; R 2 = Me, R 3 = CF 3 ) yielded the bis(ligand) adducts MCl 4 ·2HL (M = Zr, R 1 = Pr i or Ph; R 2 = R 3 = Me; or R 1 = Pr i , R 2 = Me, R 3 = CF 3 ; M = Ti, R 1 = Pr i or CH 2 CH=CH 2 , R 2 = R 3 = Me). Reaction of MCl 4 with the alkali-metal salts of the β-aminoketone ligands yielded the bis(ligand) complexes [M(R 1 NCMe=CHCMe=O) 2 Cl 2 ] (M = Zr, R 1 = Ph, p-ClC 6 H 4 , p-MeOC 6 H 4 or Pr i ; M = Ti, R 1 = Ph or p-MeOC 6 H 4 ). Crystal structure determinations of the isostructural compounds ZrCl 4 ·2Pr i HNCMe=CHCMe=O and TiCl 4 ·2Pr i HNCMe=CHCMe=O indicated an octahedral co-ordination environment around the metal with the trans monodentate N-O ligands bound through the oxygen only. Strong intramolecular hydrogen bonding of the hydrogen on the nitrogen with the ligand oxygen is consistent with a ligand immonium enolate structure. An X-ray study of the octahedral complex [Zr(PhNCMe=CHCMe=O) 2 Cl 2 ] indicated that the oxygens of the chelating N-O ligands are trans to each other and the chloride ligands are in a cis arrangement. The plane of one N-O chelate is in the equatorial plane of the complex and the plane of the second N-O ligand is at right angles to the first. The ligand forms a predominantly delocalised chelate ring but some ene-imine structure is apparent.