Titanocene complexes with nonlinear pseudohalide ligands: Synthesis, spectroscopic characterization and crystal structure

Binuclear titanocene complexes [Cp2Ti(tcm)]2O (4), [Cp2Ti(dca)]2O (5) and [Cp2Ti(dcnm)]2O (6) (tcm− = tricyanomethanide, dca− = dicyanamide and dcnm− = dicyanonitrosomethanide) were synthesized in moderate yields by the reaction of Cp2TiCl2 (1) with respective alkali metal pseudohalide salts in the aqueous solution. When the reaction was carried out in dry organic solvents, mononuclear compounds Cp2Ti(tcm)2 (2) and Cp2Ti(dca)2 (3) were isolated. Preparation of dipseudohalide complex Cp2Ti(dcnm)2 by this manner was unsuccessful due to decomposition of dcnm ligand resulting in formation of oxygen-bridged compound 6. All prepared compounds were characterized by elemental analysis, NMR, Raman, infrared and UV–Vis spectroscopy. Molecular structures of 2, 4 and 6 (two polymorphs) have been determined by single-crystal X-ray diffraction analysis.