Magnetism and crystal structure of an N3O3-coordinated iron(II) complex.

The reaction of [FeL(MeOH)2] {where L is the tetradentate N2O2-coordinating Schiff base-like ligand (E,E)-diethyl 2,2'-[1,2-phenylenebis(nitrilomethylidyne)]bis(3-oxobutanoate)(2-) and MeOH is methanol} with 3-aminopyridine (3-apy) in methanol results in the formation of the octahedral complex (3-aminopyridine-kappaN1){(E,E)-diethyl 2,2'-[1,2-phenylenebis(nitrilomethylidyne)]bis(3-oxobutanoato)(2-)-kappa4O3,N,N',O3'}(methanol-kappaO)iron(II), [Fe(C20H22N2O6)(C5H6N2)(CH4O)] or [FeL(3-apy)(MeOH)], in which the Fe(II) ion is centered in an N3O3 coordination environment with two different axial ligands. This is the first example of an octahedral complex of this multidentate ligand type with two different axial ligands, and the title compound can be considered as a precursor for a new class of complexes with potential spin-crossover behavior. An infinite two-dimensional hydrogen-bond network is formed, involving the amine NH group, the methanol OH group and the carbonyl O atoms of the equatorial ligand. T-dependent susceptibility measurements revealed that the complex remains in the high-spin state over the entire temperature range investigated.