Bonding studies from charge-transfer absorption and magnetic circular dichroism spectra. Part II. The complex hexacyanoferrate(III) and pentacyanoferrate(III) complexes of C4v , symmetry

Authors:
  • RGRodney Gale
    Rodney Gale
  • AMAnthony J. McCaffery
    Anthony J. McCaffery
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Abstract
Magnetic circular dichroism (m.c.d.) and absorption spectra of the hexacyanoferrate (III) ion have been measured in two host lattices at room and liquid-helium temperatures. Previous interprepations of the charge-transfer(c.t)bands have been confirmed and new assignments of the d-d transitions have been made. With the complexes [Fe(Cn)5L]n–(L = NH3, H2O, PPh3, SCN–, or N3 –) a new band has been detected, the energy of which is very sensitive to the nature of the ligand L. This band is assigned as L → Fe charge transfer and band energies follow the pattern previously observed in substituted halogeno-complexes of IrVI; namely, a particular high-energy filled molecular orbital with PPh3 moves to lower energy with the ligands H2O and NH3. The aqopentacyano-ferrate(III) complex shows indications of dimer formation in solution.