N-bonded Thiocyanate Research Articles

Synthesis, crystal structure and thermal properties of a new polymorphic modification of diisothiocyanatotetrakis(4-methylpyridine)cobalt(II)

The title compound, [Co(NCS)2(C6H7N)4] or Co(NCS)2(4-methylpyridine)4, was prepared by the reaction of Co(NCS)2 with 4-methylpyridine in water and is isotypic to one of the polymorphs of Ni(NCS)2(4-methylpyridine)4 [Kerr & Williams (1977). Acta Cryst. B33, 3589–3592 and Soldatov et al. (2004). Cryst. Growth Des. 4, 1185–1194]. Comparison of the experimental X-ray powder pattern with that calculated from the single-crystal data proves that a pure phase has been obtained. The asymmetric unit consists of one CoII cation, two crystallographically independent thiocyanate anions and four independent 4-methylpyridine ligands, all located in general positions. The CoII cations are sixfold coordinated to two terminally N-bonded thiocyanate anions and four 4-methylpyridine coligands within slightly distorted octahedra. Between the complexes, a number of weak C—H...N and C—H...S contacts are found. This structure represent a polymorphic modification of Co(NCS)2(4-methylpyridine)4 already reported in the CCD [Harris et al. (2003). NASA Technical Reports, 211890]. In contrast to this form, the crystal structure of the new polymorph shows a denser packing, indicating that it is thermodynamically stable at least at low temperatures. Thermogravimetric and differential thermoanalysis reveal that the title compound starts to decomposes at about 100°C and that the coligands are removed in separate steps without any sign of a polymorphic transition before decomposition.

Synthesis, crystal structure and thermal properties of the dinuclear complex bis-(μ-4-methylpyridine N-oxide-κ2O:O)bis-[(methanol-κO)(4-methylpyridine N-oxide-κO)bis-(thio-cyanato-κN)cobalt(II)

Reaction of Co(NCS)2 with 4-methyl-pyridine N-oxide in methanol leads to the formation of crystals of the title compound, [Co2(NCS)4(C6H7NO)4(CH4O)2] or Co2(NCS)4(4-methyl-pyridine N-oxide)4(methanol)2. The asymmetric unit consist of one CoII cation, two thio-cyanate anions, two 4-methyl-pyridine N-oxide coligands and one methanol mol-ecule in general positions. The H atoms of one of the methyl groups are disordered and were refined using a split model. The CoII cations octa-hedrally coordinate two terminal N-bonded thio-cyanate anions, three 4-methyl-pyridine N-oxide coligands and one methanol mol-ecule. Each two CoII cations are linked by pairs of μ-1,1(O,O)-bridging 4-methyl-pyridine N-oxide coligands into dinuclear units that are located on centers of inversion. Powder X-ray diffraction (PXRD) investigations prove that the title compound is contaminated with a small amount of Co(NCS)2(4-meth-yl-pyridine N-oxide)3. Thermogravimetric investigations reveal that the methanol mol-ecules are removed in the beginning, leading to a compound with the composition Co(NCS)2(4-methyl-pyridine N-oxide), which has been reported in the literature and which is of poor crystallinity.

Preparation of novel [Co(SCN)4] hybrid material: crystal structure investigation, DFT mechanistic analysis, antioxidant activity, and molecular docking study for potential inflammatory disorder control

The crystal structure of the title solvated coordination compound, [Co (SCN)4 (BtaH)2]·(BtaH)2.6(H2O), consists of discrete complexes in which the Co2+ cations are sixfold coordinated by four N-bonded thiocyanate anions and two 1-H benzotriazolium molecules to generate distorted trans-CoN6 octahedra. The discrete entities are each connected by three solvate molecules into chains via strong O—H···N hydrogen bonds. These chains are further linked by additional O—H···N, N—H···O, N—H···S, O—H···S and O—H···O hydrogen bonds into a three-dimensional network. Within this network, channels are formed that propagate along the c-axis direction and embed additional acetonitrile solvent molecules that are hydrogen-bonded to the network. In addition, density functional theory (DFT) calculations using the M06-2X/gen method were used to study the system's electronic properties. Interestingly, molecular docking and topological analyses were performed on compounds against various target anti-inflammatory receptors to investigate which targets exhibit the best binding affinities and hydrogen-bonding interactions. Done. As a result, it exhibits excellent anti-inflammatory activity, making it a suitable drug candidate for inflammatory diseases.

Synthesis, crystal structure and properties of tetra-kis-(pyridine-3-carbo-nitrile)-dithio-cyanatoiron(II) and of diaqua-bis-(pyridine-3-carbo-nitrile)-di-thio-cyanatoiron(II) pyridine-3-carbo-nitrile monosolvate.

The reaction of iron thio-cyanate with 3-cyano-pyridine (C6H4N2) leads to the formation of two compounds with the composition [Fe(NCS)2(C6H4N2)4] (1) and [Fe(NCS)2(C6H4N2)2(H2O)2]·2C6H4N2 (2). The asymmetric unit of 1 consists of one iron cation, two thio-cyanate anions and four 3-cyano-pyridine ligands in general positions. The iron cation is octa-hedrally coordinated by two N-bonded thio-cyanate anions and four 3-cyano-pyridine ligands. The complexes are arranged in columns along the crystallographic c-axis direction and are linked by weak C-H⋯N inter-actions. In 2, the asymmetric unit consists of one iron cation on a center of inversion as well as one thio-cyanate anion, one 3-cyano-pyridine ligand, one water ligand and one 3-cyano-pyridine solvate mol-ecule in general positions. The iron cation is octa-hedrally coordinated by two N-bonded thio-cyanate anions, two cyano-pyridine ligands and two water ligands. O-H⋯N and C-H⋯S hydrogen bonding is observed between the water ligands and the solvent 3-cyano-pyridine mol-ecules. In the crystal structure, alternating layers of the iron complexes and the solvated 3-cyano-pyridine mol-ecules are observed. Powder X-ray (PXRD) investigations reveal that both compounds were obtained as pure phases and from IR spectroscopic measurements conclusions on the coordination mode of the thio-canate anions and the cyano-group were made. Thermogravimetric (TG) and differential thermoanalysis (DTA) of 1 indicate the formation of a compound with the composition {[Fe(NCS)2]3(C6H4N2)4}n that is isotypic to the corresponding Cd compound already reported in the literature. TG/DTA of 2 show several mass losses. The first mass loss corresponds to the removal of the two water ligands leading to the formation of 1, which transforms into {[Fe(NCS)2]3(C6H4N2)4}n, upon further heating.

Synthesis, crystal structure and thermal behavior of tetra-kis-(3-cyano-pyridine N-oxide-κO)bis-(thio-cyanato-κN)cobalt(II), which shows strong pseudo-symmetry.

The title compound, [Co(SCN)2(C6H4N2O)4], was prepared by the reaction of cobalt(II)thio-cyanate with 3-cyano-pyridine N-oxide in ethanol. In the crystal, the cobalt(II) cations are octa-hedrally coordinated by two terminal N-bonded thio-cyanate anions and four O-bonded 3-cyano-pyridine N-oxide coligands, forming discrete complexes that are located on centers of inversion, hence forming trans-CoN2O4 octa-hedra. The structure refinement was performed in the monoclinic space group P21/n, for which a potential lattice translation and new symmetry elements with a fit of 100% is suggested. The structure can easily be refined in the space group I2/m, where the complexes have 2/m symmetry. However, nearly all of the reflections that violate the centering are observed with significant intensity and the refinement in P21/n leads to significantly lower R(F) values (0.027 versus 0.033). Moreover, in I2/m much larger components of the anisotropic displacement parameters are observed and therefore, the crystal structure is presented in the primitive unit cell. IR investigations confirm that the anionic ligands are only terminally bonded and that the cyano group is not involved in the metal coordination. PXRD investigations show that a pure crystalline phase has been obtained and measurements using simultaneously thermogravimetry and differential thermoanalysis reveal that the compound decomposes in an exothermic reaction upon heating, without the formation of a coligand-deficient inter-mediate phase.

Synthesis, crystal structure and thermal properties of bis-(aceto-nitrile-κN)bis-(3-bromo-pyridine-κN)bis-(thio-cyanato-κN)cobalt(II).

Single crystals of the title compound, [Co(NCS)2(C5H4BrN)2(C2H3N)2], were obtained by the reaction of Co(NCS)2 with 3-bromo-pyridine in aceto-nitrile. The CoII cations lie on crystallographic inversion centers and are coordinated by two N-bonded thio-cyanate anions, two 3-bromo-pyridine and two aceto-nitrile ligands thereby forming slightly distorted CoN6 octa-hedra. In the crystal, these complexes are linked by C-H⋯S and C-H⋯N hydrogen bonds into a three-dimensional network. In the direction of the crystallographic b-axis, the complexes are arranged into columns with neighboring 3-bromo-pyridine ligands stacked onto each other, indicating π-π inter-actions. The CN stretching vibration of the thio-cyanate anions is observed at 2066 cm-1, in agreement with the presence of only N-bonded anionic ligands. TG-DTA measurements reveal that in the first mass loss the aceto-nitrile ligands are removed and that in the second step, half of a 3-bromo-pyridine ligand is lost, leading to the formation of a polymeric compound with the composition [(Co(NCS)2)2(C5H4BrN)3] n already reported in the literature.

Synthesis, crystal structure and thermal properties of tetra-kis-(3-methyl-pyridine-κN)bis-(thio-cyanato-κN)nickel(II).

Reaction of Ni(NCS)2 with 3-methyl-pyridine in water leads to the formation of crystals of the title compound, [Ni(NCS)2(C6H7N)4]. All of them are of poor quality and non-merohedrally twinned but a refinement using data in HKLF-5 format leads to a reasonable structure model and reliability factors. The crystal structure of the title compound consists of discrete complexes, in which the nickel cations are sixfold coordinated by two terminal N-bonded thio-cyanate anions and four 3-methyl-pyridine ligands within slightly distorted octa-hedra. One of the 3-methyl-pyridine ligands is disordered and was refined using a split model. The discrete complexes are arranged into layers. X-ray powder diffraction proves that pure samples have been obtained, and in the IR spectrum, the CN stretching vibration is observed at 2072 cm-1, in agreement with the presence of only terminally coordinated thio-cyanate anions. Comparing the calculated powder pattern with those of the residues obtained by solvent removal from several solvates already reported in the literature proves that, in each case, this crystalline phase is formed. Assessing the crystal structures of the solvates in comparison with that of the ansolvate reveals some similarities.

Syntheses and crystal structures of the ethanol, acetonitrile and diethyl ether Werner clathrates bis-(iso-thio-cyanato-κN)tetra-kis-(3-methyl-pyridine-κN)nickel(II).

The reaction of nickel(II)thio-cyanate with 3-methyl-pyridine (3-picoline; C6H7N) in different solvents leads to the formation of crystals of bis-(iso-thio-cyanato-κN)tetra-kis-(3-methyl-pyridine-κN)nickel(II) as the ethanol disolvate, [Ni(NCS)2(C6H7N)4]·2C2H5OH (1), the acetonitrile disolvate, [Ni(NCS)2(C6H7N)4]·2CH3CN (2), and the diethyl ether monosolvate, [Ni(NCS)2(C6H7N)4]·C4H10O (3). The crystal structures of these compounds consist of NiII cations coordinated by two N-bonded thio-cyanate anions and four 3-methyl-pyridine ligands to generate NiN6 octa-hedra with the thio-cyanate groups in a trans orientation. In compounds 1 and 2 these complexes are located on centers of inversion, whereas in compound 3, they occupy general positions. In the crystal structures, the complexes are packed in such a way that cavities are formed in which the solvent mol-ecules are located. Compounds 1 and 2 are isotypic, which is not the case for compound 3. In compounds 1 and 2 the solvate mol-ecules are disordered, whereas they are fully ordered in compound 3. Disorder is also observed for one of the 3-methyl-pyridine ligands in compound 2. Powder X-ray diffraction and IR measurements show that at room temperature all compounds decompose almost immediately into the same phase, as a result of the loss of the solvent mol-ecules.

Syntheses, crystal structures and properties of tetra-kis-(3-methyl-pyridine-κN)bis-(iso-thio-cyanato-κN)manganese(II) and tetra-kis-(3-methyl-pyridine-κN)bis-(iso-thio-cyanato-κN)iron(II).

The reaction of Mn(NCS)2 or Fe(NCS)2 with 3-methyl-pyridine (C6H7N) leads to the formation of two isostructural compounds with compositions [Mn(NCS)2(C6H7N)4] (1) and [Fe(NCS)2(C6H7N)4] (2). IR spectroscopic investigations indicate that only terminally coordinated thio-cyanate anions are present. This is confirmed by single-crystal structure analysis, which shows that their crystal structures consist of discrete centrosymmetric complexes, in which the metal cations are octa-hedrally coordinated by two N-bonded thio-cyanate anions and four 3-methyl-pyridine ligands. X-ray powder diffraction (XRPD) proves that pure samples have been obtained. Thermogravimetric measurements show that decomposition starts at about 90°C and that the two coligands are removed in one step for 1 whereas for 2 no clearly resolved steps are visible. XRPD measurements of the residue obtained after the first mass loss of 1 show that a new and unknown crystalline compound has been formed.

Crystal structures of two Co(NCS)2 urotropine coordination compounds with different Co coordinations.

The reaction of Co(NCS)2 with urotropine in ethanol leads to the formation of two different compounds, namely, bis-(ethanol-κO)bis-(hexa-methyl-ene-tetra-mine-κN)bis-(thio-cyanato-κN)cobalt(II)-di-aqua-κ 2O-bis-(hexa-methyl-ene-tetra-mine-κN)bis-(thio-cyanato-κN)cobalt(II)-ethanol-hexa-methyl-ene-tetra-mine (1.2/0.8/1.6/4), [Co(NCS)2(C6H12N4)2(C2H6O)2]1.2·[Co(NCS)2(C6H12N4)2(H2O)2]0.8·1.6C2H6O·4C6H12N4, 1, and tris-(ethanol-κO)(hexa-methyl-ene-tetra-mine-κN)bis(thio-cyanato-κN)cobalt(II), [Co(NCS)2(C6H12N4)(C2H6O)3], 2. In the crystal structure of compound 1, two crystallographically independent discrete complexes are observed that are located on centres of inversion. In one of them, the Co cation is octa-hedrally coordinated to two terminal N-bonded thio-cyanate anions, two urotropine ligands and two ethanol mol-ecules, whereas in the second complex 80% of the coordinating ethanol is exchanged by water. Formally, compound 1 is a mixture of two different complexes, i.e. di-aqua-dithio-cyanato-bis-(urotropine)cobalt(II) and di-ethano-ldi-thio-cyanato-bis-(uro-trop-ine)cobalt(II), that contain additional ethanol and urotropine solvate mol-ecules leading to an overall composition of [Co(NCS)2(urotropine)2(ethanol)1.2(H2O)0.8·0.8ethanol·4urotropine. Both discrete complexes are linked by inter-molecular O-H⋯O and O-H⋯N hydrogen bonding and additional urotropine solvate mol-ecules into chains, which are further connected into layers. These layers combine into a three-dimensional network by pairs of centrosymmetric inter-molecular C-H⋯S hydrogen bonds. In the crystal structure of compound 2, di-thio-cyanato-(urotropine)tri-ethano-lcobalt(II), the cobalt cation is octa-hedrally coordinated to two terminal N-bonded thio-cyanate anions, one urotropine ligand and three ethanol mol-ecules into discrete complexes, which are located in general positions. These complexes are linked by inter-molecular O-H⋯N hydrogen bonding into layers, which are further connected into a three-dimensional network by inter-molecular C-H⋯S hydrogen bonding.

Synthesis, crystal structure and thermal properties of bis-(1,3-di-cyclo-hexyl-thio-urea-κS)bis(iso-thiocyanato-κN)cobalt(II).

Crystals of the title compound, [Co(NCS)2(C13H24N2S)2], were obtained by the reaction of Co(NCS)2 with 1,3-di-cyclo-hexyl-thio-urea in ethanol. Its crystal structure consists of discrete complexes that are located on twofold rotation axes, in which the CoII cations are tetra-hedrally coordinated by two terminal N-bonded thio-cyanate anions and two 1,3-di-cyclo-hexyl-thio-urea ligands. These complexes are linked via inter-molecular N-H⋯S and C-H⋯S hydrogen bonding into chains, which elongate in the b-axis direction. These chains are closely packed in a pseudo-hexa-gonal manner. The CN stretching vibration of the thio-cyanate anions located at 2038 cm-1 is in agreement with only terminal bonded anionic ligands linked to metal cations in a tetra-hedral coordination. TG-DTA measurements prove the decomposition of the compound at about 227°C. DSC measurements reveal a small endothermic signal before decomposition at about 174°C, which might correspond to melting.

Crystal structure of di-ethano-lbis(thio-cyanato)-bis(urotropine)cobalt(II) and tetra-ethano-lbis(thio-cyanato)-cobalt(II)-urotropine (1/2).

The reaction of one equivalent Co(NCS)2 with four equivalents of urotropine (hexa-methyl-ene-tetra-mine) in ethanol leads to the formation of two compounds, namely, bis-(ethanol-κO)bis-(thio-cyanato-κN)bis-(urotropine-κN)cobalt(II), [Co(NCS)2(C6H12N4)2(C2H6O)2] (1), and tetra-kis-(ethanol-κO)bis-(thio-cyanato-κN)cobalt(II)-urotropine (1/2), [Co(NCS)2(C2H6O)4]·2C6H12N4 (2). In 1, the Co cations are located on centers of inversion and are sixfold coordinated by two terminal N-bonded thio-cyanate anions, two ethanol and two urotropine ligands whereas in 2 the cobalt cations occupy position Wyckoff position c and are sixfold coordinated by two anionic ligands and four ethanol ligands. Compound 2 contains two additional urotropine solvate mol-ecules per formula unit, which are hydrogen bonded to the complexes. In both compounds, the building blocks are connected via inter-molecular O-H⋯N (1 and 2) and C-H⋯S (1) hydrogen bonding to form three-dimensional networks.

Synthesis and crystal structure of di-aqua-bis-(hexa-methyl-enetramine-κN)bis-(thio-cyanato-κN)cobalt(II)-hexa-methyl-ene-tetra-mine-aceto-nitrile (1/2/2).

The crystal structure of the title solvated coordination compound, [Co(NCS)2(C6H12N4)2(H2O)2]·2C6H12N4·2C2H3N, consists of discrete complexes in which the Co2+ cations (site symmetry ) are sixfold coordinated by two N-bonded thio-cyanate anions, two water mol-ecules and two hexa-methyl-ene-tetra-mine (HMT) mol-ecules to generate distorted trans-CoN4O2 octa-hedra. The discrete complexes are each connected by two HMT solvate mol-ecules into chains via strong O-H⋯N hydrogen bonds. These chains are further linked by additional O-H⋯N and C-H⋯N and C-H⋯S hydrogen bonds into a three-dimensional network. Within this network, channels are formed that propagate along the c-axis direction and in which additional aceto-nitrile solvent mol-ecules are embedded, which are hydrogen bonded to the network. The CN stretching vibration of the thio-cyanate ion occurs at 2062 cm-1, which is in agreement with the presence of N-bonded anionic ligands. XRPD investigations prove the formation of the title compound as the major phase accompanied by a small amount of a second unknown phase.

Synthesis, crystal structure and thermal properties of poly[bis-[μ-3-(amino-meth-yl)pyridine-κ2 N:N']bis(thio-cyanato-κN)manganese(II)

The reaction of Mn(NCS)2 with a stoichiometric amount of 3-(amino-meth-yl)pyridine in ethanol led to the formation of the title compound, [Mn(NCS)2(C6H8N2)2] n , which is isotypic to its Zn, Co and Cd analogues. The manganese cation is located on a centre of inversion and is octa-hedrally coordinated in an all-trans configuration by two terminal N-bonded thio-cyanate anions as well as four 3-(amino-meth-yl)pyridine co-ligands, of which two coordinate with the pyridine N atom and two with the amino N atom. The 3-(amino-meth-yl)pyridine co-ligands connect the MnII cations into layers extending parallel to (10). These layers are further connected into a three-dimensional network by relatively strong inter-molecular N-H⋯S hydrogen bonding. Comparison of the experimental X-ray powder diffraction pattern with the calculated pattern on the basis of single-crystal data proves the formation of a pure crystalline phase. IR measurements showed the CN stretching vibration of the thio-cyanate anions at 2067 cm-1, which is in agreement with the presence of terminally N-bonded anionic ligands. TG-DTA measurements revealed that the title compound decomposes at about 500 K.

Synthesis, crystal structure and thermal properties of poly[bis-[μ2-3-(amino-meth-yl)pyridine]-bis-(thio-cyanato)-cobalt(II)

The reaction of Co(NCS)2 with 3-(amino-meth-yl)pyridine as coligand leads to the formation of crystals of the title compound, [Co(NCS)2(C6H8N2)2] n , that were characterized by single-crystal X-ray analysis. In the crystal structure, the CoII cations are octa-hedrally coordinated by two terminal N-bonded thio-cyanate anions as well as two pyridine and two amino N atoms of four symmetry-equivalent 3-(amino-meth-yl)pyridine coligands with all pairs of equivalent atoms in a trans position. The CoII cations are linked by the 3-(amino-meth-yl)pyridine coligands into layers parallel to the ac plane. These layers are further linked by inter-molecular N-H⋯S hydrogen bonding into a three-dimensional network. The purity of the title compound was determined by X-ray powder diffraction and its thermal behavior was investigated by differential scanning calorimetry and thermogravimetry.

Synthesis, crystal structure, high-resolution l13Cd and 13C MAS NMR investigation and dielectric study of [C2H10N2]Cd (SCN)4

A new crystalline polymer compound [C2H10N2]Cd (SCN)4 was synthesized and analyzed using XRD single crystal, differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), complex impedance and solid state 13C and 113Cd CP/MAS NMR. The crystal structure shows that the cadmium atoms have a S4N2-hexa-coordination sphere, exhibiting pseudo-octahedral geometry. The Cd(II) atoms are bridged by two SCN− anions generating 1D polymeric chains. Crystal packing with significantly different interactions was determined by Hirshfeld surface analysis and discussed herein. The crystal packing was assured by mean of hydrogen bonds, Van der Waals and π-π interactions. Solid state 113Cd CP/MAS NMR shows that each distinct cadmium site in the cadmium thiocyanates exhibits multiplets that result from 113Cd,14N spin-spin coupling. Examination of the 13C CP/MAS NMR line shapes allows direct measurement of the indirect spin-spin coupling constants 1J(14N, 13C) = 28 Hz and 2J(111/113Cd,13C) = (75+8)Hz, for the unique N-bonded thiocyanate ligand. DSC analysis shows a phase transition at about 359 K. The temperature dependence of bulk conductivity σ(Rp) and relaxation frequency (fr) were described and discussed by the use of the Arrhenius relationship. The frequency dependence of the real part of the AC conductivity in both phases follows the Jonscher's universal dynamic law. The evolution of S(T) as function of temperatures suggests that the quantum mechanical tunneling QMT mechanism prevails in phases I and II.

Crystal structure of bis-(tetra-methyl-thio-urea-κS)bis(thio-cyanato-κN)cobalt(II).

In the course of systematic investigations on the synthesis of Co(NCS)2 coordination compounds with different thio-urea ligands, the title compound, [Co(NCS)2(C5H12N2S)2], was obtained. In this compound the CoII cations are coordinated by two crystallographically independent N-bonded thio-cyanate anions and two tetra-methyl-thio-urea ligands into discrete complexes that are located in general positions and show a strongly distorted tetra-hedral geometry. Inter-molecular C-H⋯S hydrogen bonds of different strength can be observed between the discrete complexes, which are connected by pairs of hydrogen bonds into zigzag-like chains that elongate in the b-axis direction. These chains are additionally linked by strong C-H⋯S hydrogen bonds along the a-axis direction, resulting in the formation of layers that are parallel to the ab plane. There is also one weak intra-molecular C-H⋯S hydrogen bond between two neighbouring thio-urea ligands within the complexes. Comparison of the experimental PXRD pattern with that calculated from the single-crystal data prove that a pure phase has been obtained. Thermoanalytical investigations reveal that this compound melts at 364 K and decomposes upon further heating.

Crystal structure of bis(4-benzoyl-pyridine-κN)bis(methanol-κO)bis(thio-cyanato-κN)nickel(II) methanol monosolvate.

The asymmetric unit of the title compound, [Ni(NCS)2(C12H9NO)2(CH3OH)2]·CH3OH, comprises one NiII cation, two thio-cyanate anions, two 4-benzoyl-pyridine coligands, two coordinating, as well as one non-coordinating methanol mol-ecule. The NiII cation is coordinated by two terminally N-bonded thio-cyanate anions, the N atoms of two 4-benzoyl-pyridine coligands and the O atoms of two methanol ligands within a slightly distorted octa-hedron. Individual complexes are linked by inter-molecular O-H⋯S hydrogen bonding into chains parallel to [010] that are further connected into layers parallel to (10) by C-H⋯S hydrogen bonds. Additional C-H⋯O hydrogen-bonding inter-actions lead to the formation of a three-dimensional network that limits channels extending parallel to [010] in which the non-coordinating methanol mol-ecules are located. They are hydrogen-bonded to the coordinating methanol mol-ecules. X-ray powder diffraction revealed that the compound could not be prepared as a pure phase.

Trimorphism of Zn(NCS)2(4-dimethylaminopyridine)2: Crystal Structures, Thermodynamic Relations, and Comparison with the Co(II) Polymorphs

Reaction of Zn(NCS)2 with 4-dimethylaminopyridine (DMAP) leads to the formation of three polymorphic modifications of Zn(NCS)2(DMAP)2 (I–Zn, II–Zn, and III–Zn), of which only the crystal structure of I–Zn is reported in literature. In all three modifications the Zn(II) cations are tetrahedrally coordinated by two terminal N-bonded thiocyanate anions and two DMAP ligands forming discrete complexes, which differ in the dihedral angle between the DMAP ring planes and the arrangement of the complexes in the crystals. All three modifications show melting, and the thermodynamic relations and the transition behavior were investigated by temperature-dependent X-ray powder diffraction, differential scanning calorimetry, thermomicroscopy, and solvent-mediated conversion experiments. These reveal that I–Zn and II–Zn as well as II–Zn and III–Zn are related by enantiotropism, whereas I–Zn and III–Zn are related by monotropism. The thermodynamic transition temperature between I–Zn and II–Zn is much lower than that betw...

Synthesis, crystal structure and properties of Cd(NCS)2 coordination compounds with two different Cd coordination modes

Abstract Reaction of Cd(NCS)2 with 4-methoxypyridine leads to the formation of four new compounds, of which one crystallizes in two different polymorphs. In Cd(NCS)2(4-methoxypyridine)4·(4-methoxypyridine)2 (1) and Cd(NCS)2(4-methoxypyridine)4 (2-I and 2-II) discrete complexes are found, in which the Cd cations are octahedrally coordinated by four 4-methoxypyridine co-ligands and two terminally N-bonded thiocyanate anions. For the polymorphs 2-I and 2-II no single crystals are available and therefore, the corresponding Mn(II) compound (2-I-Mn) was prepared, which is isotypic to 2-I, as proven by a Rietveld refinement. The crystal structure of 2-II was solved and refined from XRPD data. In [Cd(NCS)2(4-methoxypyridine)2] n (3), the Cd cations are also octahedrally coordinated but linked into linear chains by pairs of thiocyanate anions with all ligands in trans-position. {[Cd(NCS)2]3(4-methoxypyridine)5} n (4) also consists of chains but two different Cd coordination modes are observed. Two of the three crystallographically independent Cd cations show an octahedral coordination with a trans- or cis-arrangement of the N and S atoms of the anionic ligands, whereas the third one is in a distorted square-pyramidal coordination, with cis-coordination of the thiocyanate N and S atoms. Measurements using simultaneous thermogravimetry and differential scanning calorimetry of 2-I and 2-II show different heating rate dependent mass steps, in which the co-ligands are removed. In some of the residues obtained after the respective TG steps compound 3 was detected but no phase pure samples could be obtained.