Structural and Electronic Properties of Iron(0) PNP Pincer Complexes

In the present work we have prepared and fully characterized several Fe(0) complexes of the type [Fe(PNP)(CO)(2)] treating Fe(II) complexes [Fe(PNP)(Cl)(2)] with KC(8) in the presence of carbon monoxide. While complexes [Fe(PNP(NMe)‐iPr)(CO)(2)], [Fe(PNP(NEt)‐iPr)(CO)(2)] adopt a trigonal bipyramidal geometry, the bulkier and more electron rich [Fe(PNP(NH)‐tBu)(CO)(2)] is closer to a square pyramidal geometry. Mössbauer spectra showed isomer shifts very close to 0 and similar to those reported for Fe(I) systems. Quadrupole splitting values range between 2.2 and 2.7 mm s(−1) both in experiments and DFT calculations, while those of Fe(I) complexes are much smaller (∼0.6 mm s(−1)).