HYDROGEN-BONDED COMPLEXES INVOLVING THE METAL ATOM AND PROTONATION OFMETALLOCENES OF THE IRON SUBGROUP

The interactions were studied of metallocenes and their permethylated analogues of the iron subgroup (M = Fe, Ru, Os) with trifluoroacetic a cid in low-polar media. IR and UV-Vis spectra, over a wide temperature range, proved that formation of the molecular hydrogen-bonded complex (OH...M) is the first stage of protonation. The ionic H-complexes of the M(+)H...O- type are formed as a result of proton transfer. The inf luences of the metal, the substituents on the Cp-ring and of the conce ntration of acid on this acid-base equilibrium are discussed.