Organolead chemistry. Part 5. Reactions of bis(η-cyclopentadienyl)lead(II) with metal halides and with unsaturated compounds

Bis(η-cyclopentadienyl)lead(II) acts as a Lewis base and forms a thermally stable, polymeric, complex with BF3. However, with weaker Lewis acids (BMe3, BPh3, or Al2Me6) no adducts are formed and with many metal halides (BCl3, Al2Cl6, TiCl3, VCl3O, or [TaMe3Cl2]) cyclopentadienyl-for-halide exchange reactions occur. The new compounds [TaMe3(η-C5H5)Cl] and a compound tentatively formulated as [TaMe3(η-C5H5)H] have been prepared in this way. The compound Pb(η-C5H5)2 also gives adducts Pb(η-C5H5)2·0.5tcne. Pb(η-C5H5)2·tcne, and Pb(η-C5H5)2·tcnq with tetracyanoethylene (tcne) and with 7,7,8,8-tetracyanoquinodimethane (tcnq). The structures of these compounds are discussed, and the presence of tcne2– or tcnq2– is deduced.