Crystal structure of bis-{(3,5-di-methyl-pyrazol-1-yl)di-hydro-[3-(pyridin-2-yl)pyrazol-1-yl]-borato}iron(II).

The structure determination of [Fe(C(13)H(15)BN(5))(2)] was undertaken as part of a project on the modification of the recently published spin-crossover (SCO) complex [Fe{H(2)B(pz)(pypz)}(2)] (pz = pyrazole, pypz = pyridyl-pyrazole). To this end, a new ligand was synthesized in which two additional methyl groups are present. Its reaction with iron tri-fluoro-methane-sulfonate led to a pure sample of the title compound, as proven by X-ray powder diffraction. The asymmetric unit consists of one complex mol-ecule in a general position. The Fe(II) atom is coordinated by two tridentate N-binding {H(2)B(3,5-(CH(3))(2)-pz)(pypz)}(-) ligands. The Fe-N bond lengths range between 2.1222†(13) and 2.3255†(15)†à , compatible with Fe(II) in the high-spin state, which was also confirmed by magnetic measurements. Other than a very weak C-H⋯N non-classical hydrogen bond linking individual mol-ecules into rows extending parallel to [010], there are no remarkable inter-molecular inter-actions.