Synthesis and Characterization of N(C2H5)4+TiF5-, N(CH3)4+TiF4Cl- , N(C4H9)4+TiF4Br- and Density functional theory calculations of TiF5-,TiF4Cl- and TiF4Br -anions

The reaction of TiF4 with salts (C2H5)4NF, (CH3)4NCl and (C4H9)4NBr, in anhydrous CH3CN produced complexes [TiF4X]- (X=F-,Cl-,Br-). These were characterized by elemental analysis, IR, UV/Visible and 81Br NMR spectroscopy. In this paper, the optimized geometries and frequencies of the stationary point and the minimum-energy paths are calculated at the B3LYP/6-311G (d,p) level of theory too. Theoretical results showed that the Ti-X (X= F, Cl, Br) bond length values for the [TiF4X]- in compounds 1-3 are 1.863, 2.453 and 2.610 A respectively. On the other hand the Ti-F bond length values in [TiF4X]- are 1.863, 1.838 and 1.837 A, respectively. These results reveal that the bond order for Ti-X bonds decrease from compounds 1 to 3, while for Ti-F bonds, the bond orders increase. These results reveal that the bond order for Ti-X bonds decrease from compounds 1 to 3, while for Ti-F bonds, the bond orders increase. It can be concluded that the decrease of Ti-X bonds lengths and the increase of Ti-F5 bond lengths in compounds 1-3 result from the increase of the hyperconjugation from compounds 1 to 3. Harmonic vibrational frequencies and infrared intensities forTiF5?, TiF4Cl? and TiF4Br? are studied by means of theoretical and experimental methods. The calculated frequencies are in reasonable agreement with the experimental values.