Control of spins by ring deformation in a diiron(iii)bisporphyrin: reversal of ClO4− and CF3SO3−ligand field strength in the magnetochemical series

Abstract

The complete reversal of the ligand field strength of ClO₄⁻ and CF₃SO₃⁻ in the magnetochemical series is observed in a diiron(III)bisporphyrin. While ClO₄⁻, as the axial ligand, gives a typical high-spin complex, just twisting the conformation of the porphyrin macrocycle gives properties of a pure intermediate-spin state with CF₃SO₃⁻, although the axial ligand strengths suggest the reverse order of spin stabilization.