Inorganic Chemistry cess Ti02 was filtered from the solution before making the nmr measurements.In contrast to the report of Caglioti and co-workers2 and in agreement with Schmitt, et al.,s we find that the TiFe2_ ion is very stable in water. Over long periods of time only a sharp singlet is seen in the F19 nmr spectrum of the solution at room temperature. (NH4)2-TiFe in a 10% HC1 solution was prepared and examined by nmr spectroscopy. The spectrum showed the presence of TiF5-H20-and TiF62~. These species were in a 2:3 ratio. The formation of TiF5-H20~is suggested to occur by the mechanism fast TiF62-+ H30+FsTiFH-+ H20FsTiFH-+ H20 F5TiH20-+ HF For TiFe2-to hydrolyze in water, an acid solution is required, because the formation of a hydrogen bond and subsequent formation of HF helps to break the Ti-F bond.This result is consistent with the reported acid-cata-lyzed fluorine exchange between SiFe2~s pecies.12 These results are also in agreement with the proposed mechanism for the acid-catalyzed hydrolysis of trans-Co(en)2F2+ where the formation of a hydrogen bond to fluorine weakens the Co-F bond.13In Figure 3 the TiF6-H20" doublet for an initial HF :TiF4 ratio of 1:1 is compared to the doublet for an initial HF:TiF4 ratio of 2:1. Exchange is much faster in the more acidic solution. We suggest that the exchange is due to exchange of both water and fluoride ion. The fluoride ion exchange is facilitated in more acidic solutions by the initial formation of a hydrogen bond, thus lending additional support for the mechanism proposed above.

coming from reaction 4: CuO-combustion analysis gave water in appropriate yield. Reaction 10 was proved by finding in the 19F nmr spectrum a pattern exactly matching that of an authentic sample of "NiPPNi"-a second-order spectrum centered at 52.2 ppm upfield of C13CF and with main outer peaks 99 cps apart. The central complex of peaks is somewhat more cleanly resolved than in the very similar spectrum of P2(CF3)4 ( 46.9 ppm; outer-peak separation, 85 cps). The infrared spectrum also identified Contribution from the Reactor Chemistry Division and the Product Certification Division,

No abstract

Articles you may be interested inElectronic and vibrational spectra of protonated benzaldehyde-water clusters, [BZ-(H2O)n≤5]H+: Evidence for ground-state proton transfer to solvent for n ≥ 3

No abstract