The Autoionization of [TiF₄] by Cation Complexation with [15]Crown‐5 To Give [TiF₂([15]crown‐5)][Ti₄F₁₈] Containing the Tetrahedral [Ti₄F₁₈]²⁻ Ion

Abstract

It's the crown that does it: The auto‐ionization of [TiF4] has been promoted by complexation with [15]crown‐5 to produce [TiF2([15]crown‐5)][Ti4F18], which contains the new tetrahedral ion [Ti4F18]2− (see picture). The thermodynamics of the [Ti4F18]2− ion relative to the [Ti2F9]− ion in the gas, solution, and solid states were calculated by density functional methods.

Interaction of TiF4 with the donor solvents SO2, PhCN, and MeCN

“…The Ti-F terminal and Ti-(m-F) bands of 2 are comparable to those of [Ti 4 F 18 ] 2À [18]. Ti-(m-F) bands of 2 are also close to those of TiF 4 [20], while Ti-F terminal bands of 2 are located at lower wavenumbers due to longer Ti-F terminal distances (1.759(1)-1.761(1) Å ) in 2 compared to (1.704-1.725 Å ) in TiF 4 [21], see Section 2.3) in agreement with other reported TiF 4 L 2 complexes.…”

“…[4]. The most downfield singlet resonance at 332.1 ppm assigned to face-[TiF 3 (PhCN) 3 ] + , the utmost upfield resonance of terminal fluorine atoms attributed to F terminal atoms of [Ti 4 F 18 ] 2À [18]. We note that the singlet resonance of face-[TiF 3 (PhCN) 3 ] + was the strongest signal in the spectrum of TiF 4 and 1 eqv.…”

“…Thus the donor power of SO 2 (DN = 6.5 AE 2.2 kcal mol À1 [10]) is presumably too small to break all the fluorine bridges in solid TiF 4 , and only oligomeric complexes are detected in SO 2 solution. Resonances of terminal fluorines were located in the range 356-264 ppm, between the resonances assigned to [TiF 3 (SO 2 ) 3 ] + (375 ppm) [10] and [Ti 4 F 18 ] 2À (264 ppm) [18], hence oligomeric complexes in solution contained face{TiF 3 (SO 2 ) 3Àn (m-F) n } (n = 1-3) fragments (Scheme 1) much like TiF 4 complexes in MeCN solution [4].…”

Preparation of the hydrocarbon-soluble trifluoro complex LTiF3 with a β-diketiminato ligand

“…Thus, the NMR data are consistent with the presence of the LTiF 3 monomer in C 6 D 6 and CD 3 CN solution at room temperature. The low temperature (230 K) 19 F NMR spectrum of 1 in CD 3 CN exhibited a mixture of complexes including the [Ti 4 F 18 ] 2À anion [14], an unassigned fluoridebridged complex and the LTiF 3 . A solution of 1 in toluene-d 8 allowed a study of the equilibria over a wide temperature range.…”

Structural chemistry of fluoride and oxofluoride complexes of titanium(IV)

“…[67]. Four TiF 6 octahedra linked through vertices form a tetrahedral group with Ti atoms in the vertices (Fig.…”