The main motivation was that M+[HFe(CO)4]− complexes appeared, a priori, as
versatile reagents. Firstly, they exhibit a hydrogen–metal bond and are therefore
expected to react with unsaturated substrates. Secondly, the negative charge makes
them potential nucleophiles or electron-transfer agents. Finally, the carbonyl ligands
make them potential carbonylation reagents or catalysts. The main applications of
hydridotetracarbonylferrates in organic synthesis and catalysis were reviewed in 1990
[10] and some other properties have been recently reported from this laboratory
[11–16].