PREPARATION AND PROPERTIES OF STABLE PROTONATION PRODUCTS OF PERMETHYLMETALLOCENECARBALDEHYDES (M=FE, RU, OS)

The products of O-protonation of metallocenecarbaldehydes C(5)Me(5)MC( 5)Me(4)CHO (M = Fe, Ru, Os) with HBF4 and CF3COOH were obtained for th e first time, the adducts [C(5)Me(5)MC(5)Me(4)CH(OH)](BF-)-B-+ being i solated in a pure state. The structures of the adducts depend on the n ature of the metal and the anion and are governed by the correlation b etween their basicities. For example, the Fe-containing adducts have a n open fulvenoid structure with an interionic hydrogen bond irrespecti ve of the nature of the anion X (X BF4-, CF3COO-). In the case of the Ru- and Os-containing adducts in which the metal atoms are more basic than iron, the competition between the metal atom and the anion for th e formation of a hydrogen bond with the OH group is clearly manifested in the IR and H-1 NMR spectra. In the presence of the weakly basic BF 4- anion, a cyclic structure with an intramolecular M...HO hydrogen bo nd is formed, while in the presence of a more basic For CF3COO- anion, it transforms to the open fulvenoid structure with an interionic hydr ogen bond. The structures of the compounds obtained were determined by IR and 1H NMR spectra, and the structure of the (C(5)Me(5)RuC(5)Me(4) CHOH)(+)...F- salt was proved by X-ray diffraction analysis.