[HFe(CO)3{P(OPh)3}]− (vide supra). An electrostatic interaction between the
hydride and the ammonium centre is also apparent. Interestingly, this interaction is
still present in solution (CD3CN), as evidenced by a strong (36%) NOE effect
between the methyl groups of the ammonium centre and the hydride.
The series of zwitterionic hydridotricarbonylferrates has also been extended to a
phosphinite–ammonium ligand ‘‘valphosium’’ derived from valinol (Eq. (18)) [43].