Synthesis, crystal structure and magnetic properties of a two-dimensional mixed-valence assembly [Fe(salen)]2[Fe(CN)5NO]

A cyanide-bridged Fe-III-Fe-II mixed-valence assembly, [Fe-III(salen)](2)[ FeII(CN)(5)NO] [ salen = N,N'-ethylenebis(salicylideneiminato) dianion], prepared by slow diffusion of an aqueous solution of Na-2[Fe(CN)(5)NO] . 2H(2)O and a MeOH solution of [Fe(salen)NO3] in an H tube, has been characterized by X-ray structure analysis, i.r. spectra and magnetic measurements. The product assumes a two-dimensional network structure consisting of pillow-like octanuclear [-Fe-II-CN-Fe-III-NC-](4) units with dimensions: Fe(II-)AC = 1.942(7) Angstrom, C-N = 1.139(9) Angstrom, Fe-III-N = 2.173(6) Angstrom, Fe-II-C-N = 178.0(6)degrees, Fe-III-N-C = 163.4(6)degrees. The Fe-II-N-O bond angle is linear (180.0degrees). The variable temperature magnetic susceptibility, measured in the 4.8-300 K range, indicates the presence of a weak intralayer antiferromagnetic interaction and gives an Fe-III-Fe-III exchange integral of -0.033 cm(-1).