Crystal structure of a salt with a protonated sugar cation and a cobalt(II) complex anion: (GlcNH, K)[Co(NCS)4]2H2O

Leibniz-Institut für Katalyse e.V., Heterogene Photokatalyse, Albert-Einstein-Str. 29a, D-18059 Rostock, Germany, Universität Rostock, Institut für Chemie, Organische Chemie, Albert-Einstein-Str. 3a, D-18059 Rostock, Germany, and Universität Rostock, Institut für Chemie, Anorganische Festkörperchemie, Albert-Einstein-Str. 3a, D-18059 Rostock, Germany. *Correspondence e-mail: Martin.Koeckerling@uni-rostock.de


Structure description
Over about the last two decades, ionic liquids containing paramagnetic complex anions (magnetic ionic liquids, MIL) have attracted great interest because of their unique properties and possible applications (Santos et al., 2014;Clark et al., 2016). During our ongoing efforts to synthesize cobalt-based ionic liquids with low melting points (Kozlova et al., 2009;Geppert-Rybczyń ska et al., 2010;Peppel et al., 2010), the title compound was obtained as a side product in an attempted synthesis of new low-melting transition-metal systems containing protonated bio-molecules, i.e. sugar-based cations.
data reports Fig. 1 shows the molecular structures of the three parts present in the asymmetric unit. The title compound consists of a potassium cation that is bonded in an eightfold fashion to two water molecules, three O atoms of two neighbouring d-(+)-glucosammonium cations, and to three S atoms of three [Co(NCS) 4 ] 2À complex anions (Fig. 2). All bond lengths and angles are in the expected ranges (Table 1).
In the crystal structure, hydrogen bonds additionally connect all the structural units. All hydrogen atoms that are attached to the N and O atoms (except one H atom of O6 that represents a water O atom) are involved in hydrogen bonding. Table 2 lists all relevant interactions up to DÁ Á ÁA distances of 3.3 Å . Fig. 3 shows a cut-out of the structure with hydrogen bonds shown as red dashed lines. The three-dimensional structure can be described as a sequence of anionic and cationic layers extending parallel to (011), stacked along [011], as shown in Fig. 4.

Figure 1
A view of the molecular structures of the cation-cation-anion triple present in the title compound, with atoms being presented as 50% displacement ellipsoids and with atom labelling.

Figure 4
The packing of the ions in the crystal structure of the title compound. Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.