Improved synthesis of KHCr(CO)5 and comparative coordination chemistry from KHCr(CO)5 and KHFe(CO)4

A practical procedure for the selective preparation of KHCr(CO)(5) is described. The use of a potassium cation in the coordination chemistry of the [HFe(CO)(4)](-) anion is completed and extended to the coordination chemistry of the [HCr(CO)(5)](-) anion: GO-substitution by phosphites, phosphines and phosphinites, and H-abstraction by aminophosphines. Most of the observed differences in reactivity between KHFe(CO)(4) and KHCr(CO)(5) can be rationalized by the stronger acidity of KHFe(CO)(4). (C) 1998 Elsevier Science S.A. All rights reserved.