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Reaction of Co(NCS)2 with 2,6-dimethylpyrazine (2,6-DMPy) leads to the formation of a compound with the composition Co(NCS)2(2,6-DMPy)4 (Co-0D) that consists of discrete complexes, in which the Co cations are octahedrally coordinated. Upon heating, half of the 2,6-DMPy ligands are removed leading to the two-dimensional coordination polymer [Co(NCS)2(2,6-DMPy)2]n (Co-2D), shown by thermogravimetry and X-ray powder diffraction. On further heating, the intermediate Co-2D loses the next 2,6-DMPy ligand and transforms into [Co(NCS)2(2,6-DMPy)]n (Co-3D). The crystal structures of Co-2D and Co-3D were solved and refined using powder X-ray diffraction data. The crystal structure of Co-2D consists of octahedrally coordinated Co cations that are linked by pairs of anionic ligands into dimers, which are further connected by single thiocyanate anions into layers. In Co-3D, octahedrally and tetrahedrally coordinated Co cations are present, that are linked by μ-1,3-bridging single thiocyanate anions into a novel three-...

The crystal structure of the title compound, [Co(NCS)2(C12H9NO)2(CH3OH)2], consists of cobalt(II) cations that are octahedrally coordinated by two N-terminal bonding thiocyanato anions, two methanol molecules and two 4-benzoylpyridine ligands into discrete complexes that are located on centres of inversion. These complexes are further linked by O—H...O hydrogen bonding between the hydroxy H atom of the methanol ligand and the carbonyl O atom of the 4-benzoylpyridine ligand of a neighboring complex into layers parallel to (101). No pronounced intermolecular interactions are observed between these layers.

The crystal structure of the title compound, [Co(NCS)2(C2H3N)2(C12H9NO)2], consists of cobalt(II) cations that are octahedrally coordinated by the N atoms of two terminal thiocyanate anions, two acetonitrile molecules and two 4-benzoylpyridine ligands. The discrete complexes are located on centres of inversion. They are connected by weak intermolecular C—H...O and C—H...S hydrogen-bonding interactions between one of the pyridine H atoms and the carbonyl O atom, and between one of the methyl H atoms of the acetonitrile molecule and the thiocyanate S atoms into layers parallel to (101). No pronounced intermolecular interactions are observed between these layers.

The crystal structure of the title cobalt(II) compound consists of discrete octa­hedral complexes that are linked by inter­molecular O—H⋯S hydrogen bonding into chains., The asymmetric unit of the title complex, [Co(NCS)2(C7H9N)2(CH3OH)2], comprises of one CoII cation located on a centre of inversion, one thio­cyanate ligand, one methanol ligand and one 3,5-di­methyl­pyridine ligand. The CoII cation is octa­hedrally coordinated by two terminal N-bonding thio­cyanate anions, two methanol mol­ecules and two 3,5-di­methyl­pyridine ligands into a discrete complex. The complex mol­ecules are linked by inter­molecular O—H⋯S hydrogen bonding into chains that elongate in the direction parallel to the b axis.

The crystal structure of the title compound consists of discrete octa­hedral complexes that are linked by inter­molecular O—H⋯S, C—H⋯Cl, C—H⋯S and C—H⋯Cl hydrogen bonding., The asymmetric unit of the title compound, [Ni(NCS)2(C5H4ClN)2(H2O)2], consists of one nickel(II) cation that is located on a center of inversion and one thio­cyanate anion, one water mol­ecule and one 2-chloro­pyridine ligand all occupying general positions. The NiII cation is octa­hedrally coordinated by two terminal N-bound thio­cyanato ligands, two aqua ligands and two N-bound 2-chloro­pyridine ligands into discrete complexes. Individual complexes are linked by inter­molecular O—H⋯S and O—H⋯Cl hydrogen-bonding inter­actions into a layered network extending parallel to the bc plane. Weak inter­actions of types C—H⋯S and C—H⋯Cl consolidate the crystal packing.

Reaction of Co(NCS)2 with 4-(hydroxymethyl)pyridine (hmpy) leads to the formation of six new coordination compounds with the composition [Co(NCS)2(hmpy))4] (1), [Co(NCS)2(hmpy)4] × H2O (1-H2O), [Co(NCS)2(hmpy)2(EtOH)2] (2), [Co(NCS)2(hmpy)2(H2O)2] (3), [Co(NCS)2(hmpy)2]n∙4 H2O (4) and [Co(NCS)2(hmpy)2]n (5). They were characterized by single crystal and powder X-ray diffraction experiments, thermal and elemental analysis, IR and magnetic measurements. Compound 1 and 1-H2O form discrete complexes, in which the Co(II) cations are octahedrally coordinated by two terminal thiocyanato anions and four 4-(hydroxymethyl)pyridine ligands. Discrete complexes were also observed for compounds 2 and 3 where two of the hmpy ligands were substituted by solvent, either water (3) or ethanol (2). In contrast, in compounds 4 and 5, the Co(II) cations are linked into chains by bridging 4-(hydroxymethyl)pyridine ligands. The phase purity was checked with X-ray powder diffraction. Thermogravimetric measurements showed that compound 3 transforms into 5 upon heating, whereas the back transformation occurs upon resolvation. Magnetic measurements did not show any magnetic exchange via the hmpy ligand for compound 5.

In the crystal structure of the title compound, [Co(NCS)2(C6H8N2)2(H2O)2]·3C6H8N2, the CoIIcation is coordinated by two terminallyN-bound thiocyanate anions, two water molecules and two 2,6-dimethylpyrazine ligands, forming a discrete complex with a slightly distorted octahedral N4O2coordination environment. The asymmetric unit contains one CoIIcation and three halves of 2,5-dimethylpyrazine solvate molecules, all entities being completed by inversion symmetry, as well as one thiocyanate anion, an aqua ligand and a 2,6-dimethylpyrazine ligand, all in general positions. In the crystal, discrete complexes are arranged in a way that cavities are formed where the noncoordinating 2,5-dimethylpyrazine molecules are located. The coordination of the latter to the metal is prevented due to the bulky methyl groups in vicinal positions to the N atoms, leading to a preferential coordination through the 2,6-dimethylpyrazine ligands. The complex molecules are linked by O—H...N hydrogen bonds between the water H atoms and the N atoms of 2,5-dimethylpyrazine solvent molecules, leading to a layered structure extending parallel to (100).

In the crystal structure of the title compound, [Ni(NCS)2(H2O)4]·4C6H8N2, the NiIIcations are coordinated by four water ligands and twotrans-coordinated terminallyN-bonded thiocyanate anions in a slightly distorted octahedral geometry. The asymmetric unit consists of a Ni2+cation located on a centre of inversion, two water molecules and one thiocyanate ligand, as well as two uncoordinated 2,5-dimethylpyrazine ligands in general positions. In the crystal, discrete complex molecules are linked into a three-dimensional network by O—H...N hydrogen bonding between the water H atoms and the 2,5-dimethylpyrazine N atoms.

In the crystal structure of the mononuclear title compound, [Mn(NCS)2(C10H8N2)2]·C10H8N2, the MnIIcation is coordinated in an all-cisconfiguration by two N-bound thiocyanate anions and two 2,2′-bipyridine ligands within a slightly distorted octahedral environment. The asymmetric unit consists of one MnIIcation, two thiocyanate anions and two 2,2′-bipyridine ligands, as well as two non-coordinating 2,2′-bipyridine ligands that are each located on centres of inversion. In the crystal structure, the discrete [Mn(NCS)2(C10H8N2)2] complex molecules are arranged in such a way that cavities are formed, in which the solvent 2,2′-bipyridine molecules are located. Apart from van der Waals forces, there are no remarkable intermolecular interactions present in the crystal structure.

In the crystal structure of the polymeric title compound, [Mn(NCS)2(C10H8N2)]n, the MnIIcations are coordinated by one chelating 2,2′-bipyridine ligand and four thiocyanate anions (twoN- and twoS-coordinating), forming a distorted [MnN4S2] octahedron. The asymmetric unit consists of one manganese cation located on a twofold rotation axis and half of a 2,2′-bipyridine ligand, the other half being generated by the same twofold rotation axis, as well as one thiocyanate anion in a general position. The MnIIcations are linked by two pairs of μ1,3-bridging thiocyanate ligands into chains along thecaxis; because the N atoms of the 2,2′-bipyridine ligands, as well as the N and the S atoms of the thiocyanate anions, are eachcis-coordinating, these chains show a zigzag arrangement.

In the crystal structure of the title compound, [Co(NCS)2(C6H8N2)2(H2O)2]·C6H8N2, the CoIIcation is coordinated by the N atoms of two terminal thiocyanate anions, the O atoms of two water molecules and two N atoms of two 2,6-dimethylpyrazine ligands. The coordination sphere of the resulting discrete complex is that of a slightly distorted octahedron. The asymmetric unit comprises a CoIIcation and half of a 2,5-dimethylpyrazine ligand, both of which are located on centres of inversion, and a water ligand, a 2,6-dimethylpyrazine ligand and one thiocyanate anion in general positions. In the crystal, the discrete complexes are arranged in such a way that cavities are formed in which the 2,5-dimethylpyrazine solvent molecules are located. The coordination of the 2,5-dimethylpyrazine molecules to the metal is apparently hindered due to the bulky methyl groups in vicinal positions to the N atoms, leading to a preferential coordination of the 2,6-dimethylpyrazine ligands. The discrete complexes are linked by O—H...N hydrogen bonds between one water H atom and the non-coordinating N atom of the 2,6-dimethylpyrazine ligands. The remaining water H atom is hydrogen bonded to one N atom of the 2,5-dimethylpyrazine solvent molecule. This arrangement leads to the formation of a two-dimensional network extending parallel to (010).

In the crystal structure of the title complex, [Mn(NCS)2(C6H8N2)(H2O)3]·2C6H8N2, the MnIIcation is coordinated by two terminallyN-bonded thiocyanate anions, three water molecules and one 2,6-dimethylpyrazine ligand within a slightly distorted N3O3octahedral geometry; the entire complex molecule is generated by the application of a twofold rotation axis. The asymmetric unit also contains an uncoordinating 2,5-dimethylpyrazine ligand in a general position. Obviously, the coordination to the 2,6-dimethylpyrazine ligand is preferred because coordination to the 2,5-dimethylpyrazine is hindered due to the bulky methyl group proximate to the N atom. The discrete complexes are linked by water-O—H...N(2,6-dimethylpyzazine/2,5-dimethylpyzazine) hydrogen bonding, forming a three-dimensional network. In the crystal, molecules are arranged in a way that cavities are formed in which unspecified, disordered solvent molecules reside. These were modelled employing the SQUEEZE routine inPLATON[Spek (2015).Acta Cryst. C71, 9–18]. The composition of the unit cell does not take into account the presence of the unspecified solvent.

In the crystal structure of the title compound, [Mn(C5H7O2)2(C12H8N2)], the Mn2+cation is coordinated by one bidentate 1,10-phenanthroline ligand and two acetylacetonate anions within a slightly distorted N2O4octahedron. The asymmetric unit consists of one Mn2+cation situated on a twofold rotation axis, one half of a 1,10-phenanthroline ligand and one acetylacetonate anion. In comparison with the previous determination based on visually estimated intensities recorded on precession photographs, the current redetermination with image-plate data reveals bond lengths and angles with much higher precision.

The whole molecule of the title compound, [Mn(NCS)2(CH3OH)2(C5H6N2)2], is generated by inversion symmetry. The MnIIion, which is located on an inversion center, is coordinated by two 4-(dimethylamino)pyridine ligands, two methanol ligands and two terminallyN-bonded thiocyanate anions, forming a slightly distorted octahedron. In the crystal, molecules are linked by O—H...S hydrogen bonds, forming chains extending along thea-axis direction.

In the crystal structure of the title compound, [Mn(C5H7O2)2(NCS)(C5H5N)], the Mn3+cation is coordinated by two acetylacetonate anions, one terminal thiocyanate anion and one pyridine ligand within a slightly distorted octahedron. The asymmetric unit consists of half a complex molecule with the Mn3+cation, the thiocyanate anion and the pyridine ligand located on a mirror plane. The acetylacetonate anion is in a general position. The title compound was previously described [Stultset al.(1975).Inorg. Chem.14, 722–730] but could only be obtained as a powder. Suitable crystals have now been obtained for a high-precision single-crystal structure determination.