Facile synthesis and structural characterization of [Cp2TiIV(NCX)(2)][AsF6](2) complexes: Adducts of Cp2Ti(AsF6)(2) with halogen cyanides (X = Cl, Br, I)

摘要

A series of adducts between the highly reactive dicationic Cp2TiIV2+ center and the weak Lewis base halogen cyanides (ClCN, BrCN, ICN) have been prepared in a facile synthesis and in quantitative yields from the reaction of Cp2Ti(AsF6)(2) with ClCN, BrCN, or ICN in liquid SO2. The extremely air-sensitive Cp2Ti(NCX)(2)(AsF6)(2)(X = Cl (1), Br (2), I (3)) complexes were characterized using IR and H-1, N-14, F-19, and As-75 NMR spectroscopy, as well as X-ray diffraction. The structures of 1-3 were determined using X-ray diffraction techniques. The synthetic route employed should generally be applicable for the synthesis of a range of new cationic (Cp2TiL22+)-L-IV (L = neutral ligand) species using anhydrous conditions and demonstrates the usefulness of liquid SO2 as a solvent for such systems. Compounds 1-3 are the first structurally characterized (Cp2TiL2)-L-IV(EF6)(2) (L = neutral ligand; E = As, Sb) complexes with the weakly coordinating AsF6- anion and are also the first adducts between cationic Cp2Mx+ (M = transition metal) centers and the halogen cyanides, which are weak Lewis bases in comparison with other nitriles such as CH3CN.