Ga-X distances, and by an estimation of the valency of X according to Donnay and Allmann.r'3*141 With the exception of F 1 and its symmetry equivalent atoms, the 0 and F atoms are p3-bridging. F 1 is pseudo p3-bridging. Two of the Ga-F distances are short (Ga 1 -F 1 197.3(3) pin, Ga2-F 1 222.3(2) pm); the remaining weaker Ga-F contact of 252.1(3) pm is between Ga 1 and F 1 B. The solvent molecules in 1.THF and 2.THF are not coordinated to the metal atoms. The linking of the six Ga atoms through F and 0 atoms causes an approach of neighboring metal atoms to 298.05(9) pm (Ga 1 . . . Ga2) and 319.6(1) pm (Ga 1 . . . Ga 2 B) ; some 70 pm shorter than the sum of their van der Waal's radii (380 pm).[L51 However, bonding Ga-Ga interactions in 2 can be discounted. ['61 Topologically related clusters can be found, for example, in organotitanium oxides: [(MeC,H4),Ti,C1,04~,~' [Cp,Ti,C1,0,], ['71 and [Cp,Ti,0,]['81 all have the same construction principle as 2, regardless of the oxidation state of the titanium. As the space-filling model shows, the central gallium fluoride oxide unit is sterically shielded by the mesityl ligands, and this explains the kinetic inertness of 2 towards attack by water.
On the basis of cryoscopic molar mass determinations in benzene, and from NMR spectroscopic investigations, we assume that 2 does not dissociate in THF or toluene (1311, n = 1.03). The I9F NMR spectrum shows two signals at 6 = -90.7 (three F) and -104.0 (one F). The 'H and I3C NMR spectra support this conclusion; two sets of signals were found, one for each of the groups of mesityl substituents in different environments, with an intensity ratio of 1 : l .
Experimental Procedure
1: Synthesis according to ref.
[4] 2: 0.54 g (1.65 mmol) of 1 was dissolved in a mixture of toluene (20 mL) and THF (2 mL). H,O (0.02 mL. 1.10 mmol) were added. The solution was stirred at room temperature for three hours and then allowed to stand. The product 2.THF separated from the solution in the form of colorless, rectangular pris- matic crystals. Yield: 0.27 g (73% with respect to I ; scaled-up reactions give corresponding yields). M.p. z 250 'C. Cryoscopic molar mass determination (benzene, c = 0.0054 M): M , =1311, n =1.03. 'HNMR (C,D,, TMS ext.): 6 = 2.09. 2.15 (s, 18H. C4-CH,). 2.51, ext.): 6 = 21.0, 21.2 (C4-CH3). 24.5, 24.8 (C2/6-CH3). 127.5. 127.7 (C3/5), 138.8, 139.0 (C4), 145.2, 145.4 (C2/6). 145.6. 145.7 (Cl); "F NMR ([DJTHF. CFCI, ext.): 6 = -98.7 (s, 3F). -104.0 (s, 1F). IR (Nujol): i[cm-'] = 2728