SYNTHESIS AND PREPARATIVE HPLC-SEPARATION OF HETERONUCLEAR OLIGOMETALLOCENES - ISOLATION OF CATIONS OF RHODOCENYLFERROCENE, 1,1'-DIRHODOCENYLFERROCENE, AND 1-COBALTOCENYLFERROCENE,1'-RHODOCENYLFERROCENE

New members of mixed metal termetallocenes, 1,1'-dirhodoceniumylferrocene II, and 1-cobaltoceniumyl-,1'-rhodoceniumylferrocene III, were prepared by statistical nucleophilic attack of dilithioferrocene on equimolar amounts of cobaltocenium and rhodocenium hexafluorophosphate. Subsequent hydride abstraction with tritylium hexafluorophosphate yielded the respective termetallocene dications. Also a new bimetallocene monocation, ferrocenylrhodocenium I, a byproduct formed form partial protonation of dilithioferrocene, was identified. The new compounds were separated from undesired metallocenes, starting metallocenes, and byproducts by means of preparative HPLC. A reversed phase system was established which is sufficiently tuneable in selectivity to separate the different metallocene cationic species. The isolated compounds were characterized by NMR, IR, and ICP.