Preparation of bistrimethylsilylmethylniobiumtetrafluoride and the application of KHF2 and n-Bu4NHF2 as fluorinating reagents

BisTiCl(3) (1), BisNbCl(4) (2) and BisNbBr(4) (3) were prepared by alkylati on of NbCl5, NbBr5 and TICl4 with Bis(2)Zn (4) (Bis=(SiMe3)(2)CH). Compound s 2 and 3 were obtained as solids in moderate yields and are sensitive to m oisture and air. In addition, the corresponding fluoride derivative of 2, i .e. BisNbF(4) (5) was prepared in moderate yield via chlorine-fluorine meta thesis employing Me3SnF (6) as a fluorinating reagent. In another attempt T i(Oi-Pr)(4) was reacted with KHF2 to give the fluorine-containing titanium cluster mu (3)-fluoro-mu (3)-oxo-tris(mu -isopropoxy)-hexakis(isopropoxy)-t ri-titanium (7). The fluorine-free tantalum cluster bis(mu (3)-oxo)-hexakis (mu -ethoxy)-octakis(mu -oxo)-tetradecakis(ethoxy)-octa-tantalum (8) was ob tained from n-Bu4NHF2 and Ta(OEt)(5). The identity of all new compounds was documented by analytical/spectroscopic (IR, H-1-, Si-29-, F-19-NMR. MS) da ta. The crystal structures of 2, 7 and 8 were determined by single crystal X-ray diffraction. (C) 2001 Elsevier Science B.V. All rights reserved.