This result was somewhat unexpected since Collman et al. previously reported
that Na+[HFe(CO)4]− does not react with PPh3 in THF at room temperature
[20]. Similarly, Siegl reported that P(CH2CH2CN)3 does not react with
[PPN]+[HFe(CO)4]− in refluxing THF [21]. It was thus decided to investigate the
reaction of K+[HFe(CO)4]− with various phosphines and phosphites in a systematic
manner, both in protic and aprotic solvents. The study was further extended to
phosphinites, phosphinite–ammoniums and aminophosphines and general reaction
mechanisms for CO substitution processes were proposed.
In the following sections, reactions involving K+[HFe(CO)4]− in protic media
were conducted in the presence of KHCO3 (see Eq. (1)), whereas reactions conducted
in aprotic solvents (THF in general ) refer to reactions carried out in the absence of
KHCO3.
2.1.1. Reaction