Titanium, zirconium and hafnium halide complexes of trithioether and triselenoether ligands

The reaction of TiX4(X = Cl or Br) with the tripodal ligands MeC(CH2SMe)(3) or MeC(CH2SeMe)(3), (L-3) in anhydrous n-hexane or CH2Cl2 produced the extremely moisture sensitive complexes [TiX4(L-3)]. These were characterised by microanalysis, IR, UV-Vis and variable temperature H-1, C-13{H-1} and Se-77 NMR spectroscopy. The NMR studies showed that in solution in CH2Cl2 the complexes contain L-3 bound as bidentates, and that pyramidal inversion and exchange between the free and coordinated chalcogen donors is rapid at room temperature. Ligand dissociation/exchange increases TiCl4<TiBr4 and MeC(CH2SMe)(3) < MeC(CH2SeMe)(3.) and attempts to isolate TiI4 analogues were unsuccessful. The reactions of [MCl4(Me2S)(2)] (M = Zr or Hf) with (L-3) in anhydrous CH2Cl2 produces white or cream 7-coordinate [MCl4(L-3)], which are insoluble in chlorocarbon solvents. The reactions of TiX4 (X = Cl, Br or I) with the trithia-macrocycles [9]aneS(3) and [10]aneS(3) produced [TiX3([n]aneS(3))]X, whilst reaction of TiCl4. SbCl5 and [9]aneS(3) in anhydrous CH2Cl2 gave [TiCl3([9]aneS(3))]SbCl6. Spectroscopic studies suggest these macrocyclic compounds contain 6-coordinate cations. [TiX3([n]aneS(3))] (n = 9 or 10) but with Zr and Hf the complexes [MCl4([n]aneS(3))] are 7-coordinate and neutral. (C) 2003 Elsevier B.V. All rights reserved.