An extremely large 57Fe Mِssbauer quadrupole splitting for a distorted tetrahedral high-spin iron(II) complex

The zero-field, solid state, 57Fe Mössbauer spectrum of the trinuclear high-spin iron(II) complex [Fe3(SC6H2iPr3−2,4,6)4∗N(SiMe3)2∗2] has been recorded at 77 K. ‘Unusually’ large quadrupole splitting values (≥3.5 mm s−1) are observed for both the distorted trigonal planar (3.60 mm s−1) and distorted tetrahedral iron atoms (4.55 mm s−1) of the complex. The quadrupole splitting of the distorted tetrahedral iron atom is extremely large and equals that previously reported as the largest. ‘Unusually’ large quadrupole splittings for high-spin iron(II) are not that unusual and, in fact, are found for several coordination numbers and geometries.