Complex metal fluorides

Several alkali metal fluoride complexes withXeOF are known, such as 3KF XeOF [12186-19-5], 3RbF -2K.eO [12186-23-1], CsF XeOF ... 

Carreira and Kruger reported facile transmetallation of silicon enolates to other soft metal enolates including Gu derivatives.499 They reasoned that the use of soft metal fluoride complexes enabled silyl metal transmetallation with catalytic use of a soft metal source. The concept is illustrated in Scheme 103. Normal Lewis acid-catalyzed reactions of silicon enolates with aldehydes proceed via activation of aldehydes by carbonyl oxygen coordination to Lewis acids, as shown in the upper equation of Scheme 103. A key step for catalytic turnover is the desilyation of 233 by the... 

The displacement of cyclooctene or C2H4 from an iridium(I) centre by a variety of chiral phosphines (L) leads to the formation of [ (L)IrCl 2] which, in conjunction with a source of F (phosphazenium fluoride), has been used for catalytic hydroamination of olefins. This combination leads to a 6.5 fold increase in the activity of the system and a total reversal in the enantioselectivity compared to that of the chloride analogue. There is no direct evidence of formation of a metal fluoride complex, but it is proposed that it may well form in situ and that this might explain these interesting results [75]. 

Figure 13. Empirical and model-predicted — aG° values for 1 1 metal fluoride complexes = 0) plotted against z,z./(xm + = 1.36 A from Ahrens (S3).

Pagenkopf, B. L. Carreira, E. M. Transition Metal Fluoride Complexes in Asymmetric Catalysis, Chem. Eur. J. 1999, 5, 3437-3442. 

Park, S., K. Ajtai, and T.P Burghardt. 1999. Inhibition of myosin ATPase by metal fluoride complexes. Biochim. Biophys. Acta 1430 127-140. 

A study of the uranium hexafluoride-metal fluoride complexes was undertaken by Sheft et al. (77) by the use of radioactive fluorine-18 exchange methods. The exchangeability of fluorine between uranium hexafluoride and metal fluorides can be used as a measure of the extent to which reaction occurs. If a complex compound actually forms between uranium hexafluoride and a metal fluoride, then the fluorine atoms become equivalent and randomization of the radioactivity occurs. Complete exchange of the fluorine atoms is found to occur between sodium fluoride labeled... 

KUL/BLO] Kul vinova, L. A., Blokhin, V. V., Mironov, V. E., Thermodynamic properties of certain transition metal fluoride complexes in aqueous salt solution, Zh. Fiz. Khim., 50, (1976), 1287-1288, in Russian, English translation in [76KUL/BL02]. Cited on pages 142, 143, 144, 145, 377, 396. 

As proposed by Miinze, the equation used a temperature-dependent dielectric constant. However, in subsequent use (Choppin 1980), the dielectric constant was treated as a variable parameter dependent on the cationic charge. The values 80,57 and 41 were estimated for for complexation involving Ca ", Ln, and Th", respectively. Using these values, it was possible to calculate the variation of AGio, function of di2- The results of the calculations are shown as the full curves in fig. 2 for metal-fluoride complexation while the points show the experimental data. The agreement between experimental data and the calculations was taken to support a model of strongly ionic nature in the bonding of fluoride anions to both lanthanide and actinide cations. 

FLUORINATION WITH McsSnF SYNTHESIS OF CYCLOPENTADIENYL-SUBSTITUTED GROUP 4 METAL FLUORIDE COMPLEXES... 

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