An iron(iii)-centred ferric wheel Fe⊂{Fe6} with a siloxane-based bis-salicylidene Schiff base.

A new iron(iii)-centred ferric wheel Fe⊂{Fe6} of the formula [Fe7(H2L)6(NCS)6](ClO4)3·10H2O, where H4L = N,N'-bis(3-carboxylsalicylidene)-1,3-bis(3-aminopropyl)tetramethyldisiloxane, was synthesised and fully characterised. 57Fe Mössbauer spectra indicate the presence of high spin (S = 5/2) Fe3+ cations adopting a slightly different coordination environment in agreement with the X-ray diffraction structure. There are competing antiferromagnetic exchange interactions along the rim (J1 = -1.00 cm-1) and the radius (J2 = -1.46 cm-1) of the wheel.