Isomerism of single-charged titanium(IV) anions [TiF n Cl5-n DMSO]-

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

“…The 19 F NMR spectra of TiF 4 in PhCN resembles the spectrum of TiF 4 in MeCN at the same temperatures [4], suggesting a similar structure for the complexes in solution. The proposed models for MeCN adducts were given in Ref.…”

“…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].…”

“…The stronger donor MeCN interacts with the TiF 4 forming oligomeric complexes as the major species in solution as well as molecular complexes [TiF 3 (MeCN) 3 ] + and TiF 4 (MeCN) 2 [3,4,17]. The solid deposited from MeCN solution was only previously characterized by elemental analysis as TiF 4 (MeCN) 2 (solid was dried under vacuum) [2(i)], while other authors [17,2(a)] reported the TiF 4 ÁMeCN adduct.…”

“…Possible structure models of oligomeric complexes in MeCN solution of TiF 4 were proposed based on the 19 F NMR data and suggested face-{TiF 3 (MeCN) 3Àn (m-F) n } (n = 1-3) fragments having terminal fluorine atoms as well as bridging fluorine atoms in cis-positions to each other [4]. To the best of our knowledge, no structurally characterized examples of 1 TiF 4 :1 L adducts have been reported to the date.…”

“…The formation of polynuclear Ti(IV) fluorine bridged complexes was established in solutions of TiF 4 in MeCN [3,4], Et 2 O [5], TiF 4 in MeCN/CH 2 Cl 2 [4] and Et 2 O/CH 2 Cl 2 [5] by means of 19 F NMR. The interaction of TiF 4 with Me 2 O in SO 2 [6], (MeO) 3 PO in MeCN [2(i)], [FSO 3 ] À in SO 2 , and [CF 3 COO] À in MeOH also afforded mixtures of oligomeric and monomeric complexes.…”