Five-co-ordinate complexes of iron(III) have been prepared with quadridentate Schiff-base ligands obtained by the condensation of 2 mol of salicylaldehyde with 1 mol of a C-substituted diamine. They are neutral high-spin iron(III) species which in some cases can crystallize as dimers. depending on the solvent of crystallization and the natures of the apical anionic ligand. the substituents in the benzene
The thermally more stable isomer of the title complex, 2,2'-[(RS,SR)-2,3-butanediylbis(nitrilomethylidene)]diphenolato-O,N,N',O'}oxovanadium(IV), [VO(C18H18N2O2)] or [VO(sal-meso-bn)] [H(2)sal-meso-bn is (RS,SR)-N,N'-bis(salicylidene)-2,3-butanediamine], in the solid state, has been determined to be the exo isomer. The two methyl groups of the central diamine moiety in the Schiff base ligand are on the same side of the N2Ooxo plane of the VN2O3 square pyramid as the oxo ligand. The V=O distance is 1.595 (2) Angstrom, and the V atom is displaced by 0.50 (1) Angstrom toward the oxo ligand from the N2O2 basal plane. There is an intermolecular V ... O-salicyl close contact of 2.972 (2) Angstrom, which is trans to the V=O bond.