The effect of medium acidity on the rate of protonation of 6-dimethylaminofulventricarbonyl-chromium, -molybdenum, -tungsten and comparison of their basicity

Protonation of 6-dimethylaminofulvenic complexes of chromium (I), molybdenum (II) and tunsten (III) carbonyls in trifluoroacetic and acetic acid solutions of differing acidity in methylene chloride has been studied using PMR and IR spectroscopy. It has been established that the complexes are protonated at the metal atom and that the protonation rate is linearly dependent on the acidity of the medium. Comparison of the basicities of complexes I–III has shown that their basicity ratio is I/II/III ? 1/150/1800.