The Crystal Structure of Ethylenediaminebis[2-(aminomethyl)pyridine]-cobalt(III) Hexacyanocobaltate(III) Dihydrate

Abstract

Abstract The crystal structure of ethylenediaminebis[2-(aminomethyl)pyridine]cobalt(III) hexacyanocobaltate(III) dihydrate, [Co(H2NCH2CH2NH2)(C5H4NCH2NH2)2][Co(CN)6]·2H2O, has been determined by the X-ray diffraction method and subsequently refined by a block-diagonal least-squares method to give R=0.050 for 5238 non-zero reflections. The crystals are triclinic with a space group P\bar1; a=9.034(2), b=17.267(2), c=8.395(2) Å, α=87.1(3), β=96.2(3), γ=104.6(3)°, and Z=2. The crystal is ionic, comprising the [Co(H2NCH2CH2NH2)(C5H4NCH2NH2)2]3+ cation and the [Co(CN)6]3− anion. The complex cation is a slightly distorted octahedron with three five-membered chelate rings in a lel conformation. The two pyridine nitrogen atoms occupy trans positions. Thus, the cation has an approximate twofold axis of rotation. The anion is also a distorted octahedron, with the coordination of CN− through the carbon atom. The cobalt atoms of the anions occupy the special positions. Two cations in the unit cell are connected by these anions through hydrogen bonds to form a three-dimensional network typical of an ionic crystal.