Crystal structure of fac-bis-[bis-(pyridin-2-yl)methan-amine]-iron(II) 1,1,3,3-tetra-cyano-2-(di-cyano-methyl-idene)propane-1,3-diide, [Fe(dipa)2](tcpd)

Abstract

In the title compound, [Fe(C₁₁H₁₁N₃)₂](C₁₀N₆), the Fe^II cation is coordinated by two bis(pyridin-2-yl)methanamine (dipa) ligands and has crystallographic twofold symmetry. There are deviations from ideal octa-hedral geometry due to the steric requirements of the ligands. The polynitrile 1,1,3,3-tetra-cyano-2-(di-cyano-methylid-ene)propane-1,3-diide (tcpd^2-) dianion is disordered about an inversion center and is not coordinated to the Fe atom. The anion is not planar but has a propeller shape. In the crystal, weak N-H⋯N inter-actions between the amine H atoms of the dipa ligands and two nitrile groups of the anion form an alternating chain of cations and anions related by the C-centering of the unit cell.

Keywords: crystal structure; iron(II) complex; polynitrile anion; terdentate ligands.