Preparation of bistrimethylsilylmethylniobiumtetrafluoride and the application of KHF 2 and n-Bu 4NHF 2 as fluorinating reagents

Abstract

BisTiCl 3 ( 1), BisNbCl 4 ( 2) and BisNbBr 4 ( 3) were prepared by alkylation of NbCl 5, NbBr 5 and TiCl 4 with Bis 2Zn ( 4) (Bis=(SiMe 3) 2CH). Compounds 2 and 3 were obtained as solids in moderate yields and are sensitive to moisture and air. In addition, the corresponding fluoride derivative of 2, i.e. BisNbF 4 ( 5) was prepared in moderate yield via chlorine–fluorine metathesis employing Me 3SnF ( 6) as a fluorinating reagent. In another attempt Ti(O i-Pr) 4 was reacted with KHF 2 to give the fluorine-containing titanium cluster μ 3-fluoro-μ 3-oxo-tris(μ- isopropoxy)-hexakis( isopropoxy)-tri-titanium ( 7). The fluorine-free tantalum cluster bis(μ 3-oxo)-hexakis(μ-ethoxy)-octakis(μ-oxo)-tetradecakis(ethoxy)-octa-tantalum ( 8) was obtained from n-Bu 4NHF 2 and Ta(OEt) 5. The identity of all new compounds was documented by analytical/spectroscopic (IR, 1H-, 29Si-, 19F-NMR, MS) data. The crystal structures of 2, 7 and 8 were determined by single crystal X-ray diffraction.