Julia Werner

Synthesis, structures, magnetic, and theoretical investigations of layered Co and Ni thiocyanate coordination polymers

Reaction of cobalt(ii) and nickel(ii) thiocyanate with ethylisonicotinate leads to the formation of [M(NCS)2(ethylisonicotinate)2]n with M = Co (2-Co) and M = Ni (2-Ni), which can also be obtained by thermal decomposition of M(NCS)2(ethylisonicotinate)4 (M = Co (1-Co), Ni (1-Ni)). The crystal structure of 2-Ni was determined by single crystal X-ray diffraction. The Ni(ii) cations are octahedrally coordinated by two N and two S bonding thiocyanate anions and two ethylisonicotinate ligands and are linked by pairs of anionic ligands into dimers, that are connected into layers by single thiocyanate bridges. The crystal structure of 2-Co was refined by Rietveld analysis and is isostructural to 2-Ni. For both compounds ferromagnetic ordering is observed at 8.7 K (2-Ni) and at 1.72 K (2-Co), which was also confirmed by specific heat measurements. Similar measurements on [Co(NCS)2(4-acetylpyridine)2]n that exhibits the same layer topology also prove magnetic ordering at 1.33 K. Constrained DFT calculations (CDFT) support the ferromagnetic interactions within the layers. The calculated exchange constants in 2-Ni were used to simulate the susceptibility by quantum Monte Carlo method. The single-ion magnetic anisotropy of the metal ions has been investigated by CASSCF/CASPT2 calculations indicating significant differences between 2-Ni and 2-Co.

Synthesis, Crystal Structures and Polymorphism of New Cadmium and Zinc Thio- and Selenocyanato Coordination Compounds with 4-Acetylpyridine as N-Donor Ligand

Reactions of cadmium(II) thio- and selenocyanate with 4-acetylpyridine in different molar ratios and in different solvents always lead to the formation of compounds of composition Cd(NCS)2(4- acetylpyridine)2 (Cd1-I) and Cd(NCSe)2(4-acetylpyridine)2 (Cd2). Both compounds are isotypic and crystallize in the monoclinic space group C2/c. In their crystal structures the Cd cations are coordinated by two N-bonded 4-acetylpyridine ligands as well as two N- and two S/Se-bonded thio- or selenocyanato anions within a slightly distorted octahedral geometry. The Cd cations are linked into chains by pairwise μ-1,3-coordinating thio- or selenocyanato anions. In one reaction single crystals of a second polymorphic modification of composition Cd(NCS)2(4-acetylpyridine)2 (Cd1-II) were obtained by accident. This modification crystallizes monoclinically in space group P21/c, exhibits the same topology of the coordination network as in Cd1-I and Cd2 but a different arrangement of the chains in the crystal. Similar investigations with Zn(II) have revealed that only one compound of composition Zn(NCS)2(4-acetylpyridine)2 can be prepared that crystallizes in the triclinic space group P1. Its structure consists of discrete complexes in which the Zn(II) cations are tetrahedrally coordinated. A corresponding selenocyanato coordination compound could not be prepared Graphical Abstract Synthesis, Crystal Structures and Polymorphism of New Cadmium and Zinc Thio- and Selenocyanato Coordination Compounds with 4-Acetylpyridine as N-Donor Ligand

Crystal structure of bis­(aceto­nitrile-κN)bis­(4-benzoyl­pyridine-κN)bis­(thio­cyanato-κN)cobalt(II)

The crystal structure of the title compound consists of discrete octahedral complexes, that are linked by intermolecular C—H⋯O and C—H⋯S hydrogen bonding into layers.

catena-Poly[[bis­(3-acetyl­pyridine-κN)cadmium]-di-μ-seleno­cyanato-κ2N:Se;κ2Se:N]

In the crystal structure of the title compound, [Cd(NCSe)2(C7H7NO)2]n, the Cd2+ cation is coordinated by two 3-acetylpyridine ligands and four μ-1,3-bridging selenocyanate anions within a slightly distorted CdN4Se2 octahedron. The asymmetric units consists of one Cd2+ cation, which is situated on a center of inversion, as well as one selenocyanate anion and one 3-acetylpyridine ligand in general positions. The metal cations are μ-1,3-bridged via the selenocyanate anions into chains along the a axis.

Poly[(μ-1,3-thio­cyanato-κN,S)(iso­nicotin­ato-κN,O)(ethanol-κO)cadmium(II)]

In the crystal structure of the title compound, [Cd(NCS)(C6H4NO2)(C2H5OH)]n, the Cd2+ cation is coordinated by one N and two O atoms of two symmetry-related isonicotinate anions, one ethanol molecule and two μ-1,3-bridging thiocyanate anions in a distorted octahedral N2O3S geometry. The metal cations are μ-1,3-bridged via thiocyanate anions into chains that are further connected into layers parallel to the ab plane by bridging isonicotinate anions. The layers are stacked along the c axis. The crystal structure is stabilized by O—H⋯O hydrogen bonds.

Crystal structure of poly[[μ-4-(hy­droxy­meth­yl)pyridine-κ2N:O][4-(hy­droxy­meth­yl)pyridine-κN](μ-thio­cyanato-κ2N:S)(thio­cyanato-κN)cadmium]

The crystal structure of the title compound, [Cd(NCS)2(C6H7NO)2]n is made up of Cd2+ cations that are coordinated by three thiocyanate ligands and three 4-(hydroxymethyl)pyridine ligands within distorted N4OS octahedra. The asymmetric unit consists of one Cd2+ cation, two thiocyanate anions and two 4-(hydroxymethyl)pyridine ligands in general positions. Two Cd2+ cations are linked by two μ-1,3 N- and S-bonding thioycanate anions into dimers which are further linked into branched chains along [100] by two μ-1,6 N- and O-bonding 4-(hydroxymethyl)pyridine ligands. One additional N-bonded 4-(hydroxymethyl)pyridine ligand and one additional N-bonded thiocyanate anion are only terminally bonded to the metal cation. Interchain O—H⋯S hydrogen bonds between the hydroxy H atoms and one of the thiocyanate S atoms connect the chains into a three-dimensional network.

Crystal structure of bis-(4-acetyl-pyridine-κN)bis-(ethanol-κO)bis-(thio-cyanato-κN)manganese(II).

In the crystal structure of the title compound, [Mn(NCS)2(C7H7NO)2(C2H5OH)2], the MnII atom is coordinated by two N-bonded thiocyanate anions, two 4-acetylpyridine ligands, and two ethanol molecules within a slightly distorted octahedron. The asymmetric unit consits of one manganese cation, located on a centre of inversion, one thiocyanate anion, one 4-acetylpyridine ligand and one ethanol molecule in general positions. The discrete complexes are connected by intermolecular O—H⋯O hydrogen bonds between the alcohol OH group and the carbonyl O atom into chains parallel to [011].

Synthesis, Crystal Structures, and Thermal and Spectroscopic Properties of Thiocyanato Coordination Compounds with 3-Acetylpyridine as a Ligand

Abstract The reaction of transition metal thiocyanates with 3-acetylpyridine (3-Acpy) leads to the formation of compounds of compositions M(NCS)2(3-Acpy)4 (M1; M = Mn, Fe, Ni) and M(NCS)2(3- Acpy)2(H2O)2 (M2; M = Mn, Fe, Ni). Thermogravimetric investigations show that in the first step some of these compounds transform into the new coordination polymers M(NCS)2(3-Acpy)2 (M3 with M = Mn, Fe and Ni), that decompose into the new compounds M(NCS)2(3-Acpy) (M4 with M = Mn and Ni) in the second step. Unfortunately, the powder patterns of compounds M3 and M4 cannot be indexed, and there are strong indications that these compounds are contaminated with a small amount of the precursor or unknown crystalline phases. IR spectroscopic investigations indicate that in compounds M3 the metal cations are linked by μ-1,3-bridging thiocyanato anions into 1D or 2D coordination polymers that are further linked by the 3-Acpy ligands in compounds M4.

Crystal structure of bis­[4-(4-chloro­benz­yl)pyridine-κN]bis­(thio­cyanato-κN)zinc

In the crystal structure of the title compound, [Zn(NCS)2(C12H10ClN)2], the Zn2+ cation is N-coordinated by two terminally bonded thiocyante anions and by two 4-(4-chlorobenzyl)pyridine ligands within a slightly distorted tetrahedron. The asymmetric unit consists of half of the discrete complex, the central Zn2+ cation of which is located on a twofold rotation axis. The discrete complexes are linked into layers via a weak intermolecular hydrogen-bonding interaction, with a H⋯Cl distance of 2.85 Å and a C—H⋯Cl angle of 151°. These layers extend parallel to the ab plane and are held together by dispersion forces only.

Crystal structure of catena-poly[[(3-tert-butyl-pyridine-κN)(4-tert-butyl-pyridine-κN)cadmium]-di-μ-thio-cyanato-κ(2) N:S;κ(2) S:N].

In the crystal structure of the title compound, [Cd(NCS)2(C9H13N)2]n, the CdII cations are coordinated in a slightly distorted octahedral geometry by one 3-tert-butylpyridine ligand, one 4-tert-butylpyridine ligand and two pairs of translationally-equivalent μ-1,3-bridging thiocyanate ligands, all of which are in general positions. These μ-1,3-bridging thiocyante anions bridge the CdII cations, forming chains that propagate parallel to the b axis.