- Thiocyanato Coordination Polymers with Isomeric Coordination Networks - Synthesis, Structures, and Magnetic Properties
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The reactions of M(NCS)2 (M = Mn, Fe, and Ni) with 4-acetylpyridine (4-Acpy) in water lead to the formation of discrete complexes of composition M(NCS)2(4-Acpy)2(H2O)2, in which the metal cations are coordinated only N-terminally to the thiocyanato anions. When heated, these precursors dehydrate, and some of them transform into compounds of composition [M(NCS)2(4-Acpy)2]n, in which the metal cations are linked by pairs of μ-1,3-bridging anionic ligands into chains (1D isomer). In contrast, the thermal decomposition of Ni(NCS)2(4-Acpy)4 or crystallization from solution leads to the formation of an isomeric 2D network of the same composition, which is thermodynamically more stable than the 1D isomer. Temperature-dependent magnetic measurements of the 1D isomer [Fe(NCS)2(4-Acpy)2]n at 200 Oe reveal antiferromagnetic ordering at TN = 4.5 K. Field-dependent measurements show a metamagnetic transition into a saturated paramagnetic phase at a critical field of ca. 700 Oe. In contrast, magnetic measurements of the 2D isomer [Ni(NCS)2(4-Acpy)2]n at 1000 Oe show a ferromagnetic transition at TC = 8.6 K, whereas only paramagnetic behavior is observed for the Ni 1D isomer.
- Werner, Julia,Run?evski, Tom?e,Dinnebier, Robert,Ebbinghaus, Stefan G.,Suckert, Stefan,N?ther, Christian
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- Transition metal complexes with pyrazole based ligands, part 15. Cobalt(iii)-, nickel(ii)- and copper(ii)-complexes with 3,5-dimethyl-1-thiocarboxamidepyrazole
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The complex formation of cobalt(II)-, nickel(II) and copper(II) sulphate hydrates with 3,5-dimethyl-1-thiocarboxamidepyrazole (HL) was studied. The influence of the anions on the course of the reaction was also examined, using nickel(II) salts with various anions. Beside the NiSO4.7H 2O the reaction has been carried out with Ni(OAc)2, Ni(CF3COO)2 and Ni(SCN)2, Compounds with the following composition were obtained: Co(L)3, Ni(L)2 and [Cu(SCN)L]2. The structure of the ligand and the Co(L)3 complex was determined by single crystal X-ray analysis, while that of the Ni(L)2 was solved by analysis of powder diffraction X-ray data, The most probable structure of the copper(II) complex is proposed on the basis of the elemental analyses data, FT-IR spectrometry and magnetic measurement. The thermal decomposition of the complexes was investigated by thermogravimetry, DSC and coupled TG-MS measurements. In the case of the nickel(II) compound, a relatively stable intermediate was detected in the 550-650 K temperature range. The composition of the intermediate, Ni(SCN)(NCS), was determined by FT-IR-spectrometry.
- Meszaros Szecsenyi,Leovac,Ja?imovi?,Pokol
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- A very low-temperature calorimeter with a (3He + 4He) dilution refrigerator. The heat capacity of trans-bis(ethylenediamine)-bis(isothiocyanato)nickel(II)
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A calorimeter with a (3He + 4He) dilution refrigerator capable of measuring heat capacity between 20 mK and 25 K has been constructed.The calorimeter works under three operational modes in accordance with the temperature region suitable for heat-capacity measurements: the isoperibol low-temperature mode covers the range below 200 mK, the adiabatic high-temperature mode is used in the range from 0.2 to 25 K, and the isoperibol third mode is adopted when the thermal relaxation time of a sample is long.The accuracy of the calorimeter has been determined indirectly by comparing heat capacities of a common sample with those measured by a 3He calorimeter whose accuracy has been established on the basis of the 1965 Calorimetry Conference Copper Standard.The heat capacity of a paramagnetic nickel complex (en = H2NCH2CH2NH2) has been measured between 0.3 and 20 K.A Schottky anomaly centred around 3.3 K was detected.This anomaly was well accounted for in terms of the zero-field splitting of a single nickel ion arising from the crystalline-field anisotropy.The best fit between theory and experiment was obtained for D/k = 8.98 K and /E//k = 1.62 K (or /E//D = 0.18) where D and E are the uni- and bi-axial crystalline-field anisotropy parameters, respectively, and k is the Boltzmann constant.The heat-capacity anomaly can likewise be accounted for in terms of different set of the parameters (D/k = -6.92 K and /E//k = 3.67 K or /E//D = 0.53) because both the sets bring about identical splitting with respect to the spin energy-level.
- Murakawa, Shigemi,Wakamatsu, Tomio,Nakano, Motohiro,Soral, Michio,Suga, Hiroshi
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- Large-ring chain and sheet polymeric metal complexes of extended-reach siloxypyridine ligands of type O[iPr2SiO(CH2)npy]2
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The preparations are reported of a range of metal complexes of Mn(II), Co(II), Ni(II) and Zn(II) with the 'extended reach' ligands O[iPr2SiO(CH2)npy]2 (n=0, 1 or 3, I-III) and with Cu(II), Cd(II) and Ag(I) for II; six of them have been shown by X-ray studies to have polymeric structures. The compounds M[O(iPr2SiOpy)2]2Cl2 (M=Co, Cu) form chains of 24-membered macrocycles, as does Co[O(iPr2SiOCH2py)2] 2I2(H2O)2. A similar structure is formed by Mn[O(iPr2SiOCH2py)2] 2Cl2 but in this case the rings are 28-membered. The complex Cu[O(iPr2SiOpy)2]Cl2 forms sheets of 52-membered macrocycles with chloride bridged Cu2Cl4 units at the node points. The structure of Cu2[O(iPr2SiOpy)2]4Cl 3 comprises sheets of 48-membered rings which are linked into pairs of sheets by linear, but weak, Cu-Cl-Cu bridges. X- and Q-band EPR spectra of the manganese compounds are also reported, as are relevant spectroscopic results for the other complexes.
- Goodgame, David M.L.,Lickiss, Paul D.,Rooke, Stephanie J.,White, Andrew J.P.,Williams, David J.
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- Tuning of the Critical Temperature in Magnetic 2D Coordination Polymers by Mixed Crystal Formation
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Reaction of Co(NCS)2 and Ni(NCS)2 with 4-acetylpyridine under different conditions leads to the formation of mixed crystals of the layered compound with the composition [CoxNi1-x(NCS)2(4-acetylpyridine)2]n (x = 0.15 0.3, 0.5, and 0.7). Mixed crystal formation was investigated by a combination of X-ray powder diffraction (XRPD), atomic absorption spectroscopy (AAS), simultaneous scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), differential scanning calorimetry (DSC), and magnetic and heat capacity measurements. Dependent on the synthetic method, homo- or heterogeneous mixed crystals were obtained as already indicated by XRPD, where significant differences to the pattern of physical mixtures of the homometallic counterparts [M(NCS)2(4-acetylpyridine)2]n with M = Co or Ni) with the same Co/Ni ratio are observed. Mixed crystals can also be obtained from physical mixtures under thermodynamic control, indicating that they are more stable than the homometallic compounds. This is further supported by AAS, which indicates that the solubility of the mixed crystals is lower than that of the homometallic compounds. Magnetic and heat capacity measurements show a linear increase of the critical temperature of magnetic ordering with increasing Ni content and also confirm that homogeneous samples were obtained.
- Wellm, Carsten,Rams, Micha?,Neumann, Tristan,Ceglarska, Magdalena,N?ther, Christian
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- A thermochemical investigation of guest-host interactions in labile Werner clathrates of the [Ni(4-EtPy)4(NCS)2]·G type (G = methyl derivatives of benzene)
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The stoichiometry of thermal decomposition has been studied for (I): [Ni(4-EtPy)4(NCS)2] as a host complex as well as for its clathrates [Ni(4-EtPy)4(NCS)2]·G where guest molecule G - toluene, (II): T, (III): o-xylene (o-X) and (IV): p-xylene (p-X). The loss of volatile components proceeds in three steps (-2L, -1L, -1L) for I and in four steps (-G, -2L, -1L, -1L) for II, III and IV. DSC and X-ray powder measurements indicated a phase transition in all compounds under study. However, this process is overlapped by the escape of G in II and III. The differences in enthalpy changes are associated with different guest-host interactions in the particular clathrates.
- Jona,Simon,Jorik,Koman
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- Field effects to slow magnetic relaxation in a mononuclear Ni(II) complex
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A mononuclear Ni(ii) complex [Ni(NCS)2(nqu)2(H2O)2]·2nqu (nqu-5-nitroquinoline) shows a field induced slow magnetic relaxation with three relaxation domains. The relaxation time for the low-frequency mode is as slow as τ = 0.3 s at T = 1.9 K and BDC = 0.4 T.
- Lomjansky,Moncol,Rajnák,Titi?,Bo?a
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- Reversible and Topotactic Solvent Removal in a Magnetic Ni(NCS)2 Coordination Polymer
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Reaction of Ni(NCS)2 with 4-(Boc-amino)pyridine in acetonitrile leads to the formation of a new coordination polymer with the composition Ni(NCS)2(4-(Boc-amino)pyridine)2·MeCN (1-MeCN). In the crystal structure the Ni(II) cations are linked by the anionic ligands into chains that are further connected into layers by intermolecular N-H···O hydrogen bonding. These layers are stacked and channels are formed, in which acetonitrile molecules are located. Solvent removal leads to the ansolvate 1, which shows microporosity as proven by sorption measurements. Single crystal X-ray investigations reveal that the solvent removal leads to a change in symmetry from primitive to C-centered, which is reversible and which proceeds via a topotactic reaction leaving the network intact. The magnetic properties of 1-MeCN and 1 are governed by the ferromagnetic exchange between spins of Ni(II) forming chains. The susceptibility and specific heat for such a quantum Heisenberg chain of S = 1 spins with zero-field splitting are calculated using the DMRG method and compared with the experimental results.
- Suckert, Stefan,Rams, Micha?,Rams, Marek M.,N?ther, Christian
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- Isoquinoline-based Werner clathrates with xylene isomers: Aromatic interactions vs. molecular flexibility
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The crystal structures of the Werner clathrates Ni(NCS)2(isoquinoline)4 (H) with para-xylene (px), meta-xylene (mx) and ortho-xylene (ox) have been elucidated. The kinetics of thermal decomposition of the three inclusion compounds were performed using the isothermal technique of Flynn and Wall. Selectivity of H for the xylene isomers was determined for both the liquid and vapour phase binary mixtures of the xylenes. The chosen ligand has a larger aromatic system to improve the possible π interactions between H and the selected guests. The planarity of the isoquinoline ligand causes H rigidity and its selectivity was compared to a related Werner complex containing the more flexible 4-phenylpyridine. This journal is
- Wicht, Merrill M.,Báthori, Nikoletta B.,Nassimbeni, Luigi R.
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- New isomeric Ni(NCS)2 coordination compounds: Crystal structures, magnetic properties as well as: Ex situ and in situ investigations on their synthesis and transition behaviour
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The reaction of Ni(NCS)2 with 3-ethylpyridine in water leads to the formation of two known modifications of Ni(NCS)2(3-ethylpyridine)4 (1-I and 1-II) as well as of Ni(NCS)2(3-ethylpyridine)2(H2O)2 (2) that consist of discrete complexes. If the synthesis is performed in ethyl acetate, the new compound [Ni(NCS)2(3-ethylpyridine)2]n (3-lc) formed that comprises linear and corrugated Ni(NCS)2 chains in one crystal. By changing the solvent to dichloromethane, a solvate of compound 3 is obtained that consists exclusively of corrugated chains (3c-CH2Cl2). 3c-CH2Cl2 is unstable and transforms immediately into 3-lc. Upon heating the precursor complexes 1-I, 1-II and 2, the 3-ethylpyridine ligands are removed in two steps leading to a mixture of 3-lc and an additional isomer of 3 (3-l) in the first step that decomposes upon further heating into a compound with the composition [Ni(NCS)2(3-ethylpyridine)]n (4). Ex and in situ XRPD measurements reveal that a mixture of two modifications (4-I and 4-II) is always formed, preventing their structure determination by XRPD. Time dependent investigations in solution prove that 3-l is formed under kinetic control and transforms into 3-lc within several hours that is thermodynamically stable at roomerature. Structure analysis of 3-l shows that in contrast to 3-lc and 3c-CH2Cl2 this isomer consists exclusively of linear Ni(NCS)2 chains. Magnetic measurements of the new chain compounds 3-l and 3-lc shows χT values that are typical for Ni(ii) cations with S = 1. For 3-l the exchange constant was determined by fitting of the magnetic data leading to a value that is similar to that of [Ni(NSC)2(2,2′-bipyridine)2]n.
- Ceglarska, Magdalena,Dinnebier, Robert E.,Gallo, Gianpiero,N?ther, Christian,Neumann, Tristan,Rams, Micha?,Wellm, Carsten
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- Structural Diversity in Ni Chain Coordination Polymers: Synthesis, Structures, Isomerism and Magnetism
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Reaction of Ni(NCS)2 with different co-ligands based on pyridine derivatives substituted in 4-position leads to the formation of 1D coordination polymers with the composition [Ni(NCS)2(co-ligand)2]n, in which the metal cations are coordinated octahedrally by two S- and two N-bonding thiocyanate anions as well as two neutral co-ligands and are linked into chains by μ-1,3-bridging thiocyanate anions. Dependent on the nature of the co-ligand, novel isomers with linear and corrugated chains are observed, in which the Ni cations are trans- or cis-cis-trans coordinated. This also includes a dimer and two isomeric chain compounds with 4-chloropyridine as ligand, of which one is metastable at room-temperature. For all these compounds, together with several additional Ni(NCS)2 chain compounds, the values of the intrachain exchange interaction J are extracted based on magnetic measurements. The values of J for 13 different Ni(NCS)2 compounds are compared with the structural results to investigate if there are some simple relations between the magnetic exchange, the metal coordination and the chain geometry. The low temperature magnetic properties of the Ni(NCS)2 dimer and the chain compounds are also discussed based on magnetic and specific heat measurements.
- Jochim, Aleksej,Rams, Micha?,Neumann, Tristan,Wellm, Carsten,Reinsch, Helge,Wójtowicz, Gabriela M.,N?ther, Christian
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- Synthesis, Crystal Structures and Properties of Ni(NCS)2-3-Cyanopyridine Coordination Compounds including a Ferromagnetic Layered Compound
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Reactions of Ni(NCS)2 and 3-cyanopyridine in different solvents lead to the formation of Ni(NCS)2(3-cyanopyridine)4 (1) already reported in the literature, Ni(NCS)2(3-cyanopyridine)2(H2O)2 (2), Ni(NCS)2(3-cyanopyridine)2(CH3OH)2 (3), Ni(NCS)2(3-cyanopyridine)2(CH3CN)2 (4) and Ni(NCS)2(3-cyanopyridine)2 (5). The crystal structures of 1–4 consist of discrete octahedral complexes, in which the thiocyanate anions, as well as the 3-cyanopyridine coligands, are only terminally N-bonded. In compound 5 the Ni cations are octahedrally coordinated and linked by pairs of thiocyanate anions into dinuclear units that are further connected into layers by single μ-1,3-bridging anionic ligands. TG-DTA measurements of the discrete complex 1 reveal that in the first step half of the coligands are emitted leading to the formation of compound 5. In contrast, compounds 2 and 3 transform into a new crystalline phase of the same composition (6) upon heating that should also contain μ-1,3-bridging anionic ligands, but the outcome of this reaction strongly depends on the reaction conditions. The acetonitrile complex 4 is unstable at room temperature and decomposes into a mixture of different phases including the aqua complex 2. Magnetic measurements of compound 5 prove a ferromagnetic transition at Tc=6.0 K. This result is compared to those obtained for other thiocyanate compounds exhibiting a similar layer topology.
- Krebs, Christoph,Thiele, Solveig,Ceglarska, Magdalena,N?ther, Christian
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- Synthesis, Crystal Structures and Properties of Polymorphic and Isomeric Nickel(II)thiocyanate Coordination Compounds with 3-Bromopyridine as Coligand
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Reaction of different molar ratios of Ni(NCS)2 and 3-bromopyridine in water, methanol or acetonitrile leads to the formation of two polymorphs of composition Ni(NCS)2(3-bromopyridine)4 (1-I and 1-II), as well as Ni(NCS)2(3-bromopyridine)2(H2O)2 (2), Ni(NCS)2(3-Bromopyridine)2(CH3OH)2 (3), Ni(NCS)2(3-bromopyridine)2 ? CH3CN (4) and Ni(NCS)2(3-bromopyridine)2 (5). Compounds 1-I, 1-II, 2 and 3 consist of discrete octahedral complexes with terminal N-bonded anionic ligands. In compound 4 the Ni cations are cis-cis-trans coordinated and linked into corrugated chains by pairs of μ-1,3-bridging thiocyanate anions. Solvent mediated conversion experiments prove that form 1-I represents the thermodynamically stable polymorph at room temperature. TG-DTA measurements reveal that upon heating compounds 1-I, 1-II, 2 and 3 lose their coligands stepwise and transform into the new crystalline phase 5 that can also be obtained from solution if the reaction is performed in n-butanol. If the acetonitrile solvate molecules are removed from compound 4, it also transforms into 5. DC magnetic measurements for compound 4 show a maximum, which is indicative for antiferromagnetic ordering, whereas for compound 5 no magnetic ordering is observed. For both compounds, the ferromagnetic exchange constants were determined.
- Krebs, Christoph,Ceglarska, Magdalena,N?ther, Christian
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- Synthesis, structures, magnetic, and theoretical investigations of layered Co and Ni thiocyanate coordination polymers
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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
- Suckert, Stefan,Rams, Micha?,B?hme, Michael,Germann, Luzia S.,Dinnebier, Robert E.,Plass, Winfried,Werner, Julia,N?ther, Christian
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- Synthesis, Crystal Structures, and Properties of Ni(NCS)2-4-methoxypyridine Coordination Compounds
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Two polymorphs of Ni(NCS)2(4-methoxypyridine)4 (1-I, 1-II) as well as compounds with the compositions Ni(NCS)2(4-methoxypyridine)4(MeCN)1.33 (1-MeCN), Ni(NCS)2(4-methoxypyridine)2(MeCN)2 (2) and [Ni(NCS)2(4-methoxypyridine)2]n (3) are reported. For 1-II no single crystals were obtained, but this compound is isotypic to the Fe analog 1-II-Fe. The crystal structures of 1 and 2 show discrete octahedral NiII complexes, whereas in 3 the cations are connected by pairs of thiocyanate anions into chains. Solvent mediated conversion experiments reveal that 1-I is thermodynamically stable at room temperature and differential scanning calorimetry shows no indication for a polymorphic transition. The thermal behavior of 1-I, 1-II, and 2 was investigated by simultaneous thermogravimetry and differential scanning calorimetry, which shows that they decompose in two discrete steps. In the first step compound 3 is formed as an intermediate, which decomposes on further heating into Ni(NCS)2. Time dependent XRPD investigations prove, that 2 transforms already at room temperature into 3. Upon heating 1-MeCN transforms into 1-I in the first TG step, which decomposes on further heating into 3. Investigation of the magnetic behavior of 3 shows dominating ferromagnetic exchange interactions along the chains with J = 5.9(1) K. Susceptibility measurements indicate antiferromagnetic ordering, which was confirmed by specific heat measurements, revealing that magnetic ordering occurs at 1.91(5) K.
- Jochim, Aleksej,Ceglarska, Magdalena,Rams, Micha?,N?ther, Christian
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- Structures, Thermodynamic Relations, and Magnetism of Stable and Metastable Ni(NCS)2 Coordination Polymers
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Reaction of Ni(NCS)2 with 4-aminopyridine in different solvents leads to the formation of compounds with the compositions Ni(NCS)2(4-aminopyridine)4 (1), Ni(NCS)2(4-aminopyridine)2(H2O)2 (2), [Ni(NCS)2(4-aminopyridine)3(MeCN)]·MeCN (3), and [Ni(NCS)2(4-aminopyridine)2]n (5-LT). Compounds 1, 2, and 3 form discrete complexes, with octahedral metal coordination. In 5-LT the Ni cations are linked by single thiocyanate anions into chains, which are further connected into layers by half of the 4-aminopyridine coligands. Upon heating, 1 transforms into an isomer of 5-LT with a 1D structure (5-HT), that on further heating forms a more condensed chain compound [Ni(NCS)2(4-aminopyridine)]n (6) that shows a very unusual chain topology. If 3 is heated, a further compound with the composition Ni(NCS)2(4-aminopyridine)3 (4) is formed, which presumably is a dimer and which on further heating transforms into 6 via 5-HT as intermediate. Further investigations reveal that 5-LT and 5-HT are related by enantiotropism, with 5-LT being the thermodynamic stable form at room-temperature. Magnetic and specific heat measurements reveal ferromagnetic exchange through thiocyanate bridges and magnetic ordering due to antiferromagnetic interchain interactions at 5.30(5) K and 8.2(2) K for 5-LT and 6, respectively. Consecutive metamagnetic transitions in the spin ladder compound 6 are due to dipolar interchain interactions. A convenient formula for susceptibility of the ferromagnetic Heisenberg chain of isotropic spins S = 1 is proposed, based on numerical DMRG calculations, and used to determine exchange constants.
- Neumann, Tristan,Ceglarska, Magdalena,Germann, Luzia S.,Rams, Micha?,Dinnebier, Robert E.,Suckert, Stefan,Jess, Inke,N?ther, Christian
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- Synthesis, Structures, and Properties of Transition Metal Thiocyanato Coordination Compounds with 4-(4-Chlorobenzyl)pyridine as Ligand
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Reactions of transition metal thiocyanates with 4-(4-chlorobenzyl)pyridine (Clbp) lead to the formation of compounds of composition M(NCS)2(4-(4-chlorobenzyl)pyridine)4 (Mn-1, Fe-1/I, Fe-1/II, Ni-1, and Cd-1) and M(NCS)2(4-(4-chlorobenzyl)pyridine)2 (Mn-2, Ni-2, and Cd-2). In the crystal structures of compounds M-1 the metal cations are octahedrally coordinated by two terminal N-bonded thiocyanato anions and four Clbp ligands, whereas in compounds M-2 the metal cations are linked by μ-1, 3-bridging anionic ligands. IR spectroscopic investigations show that the value of the asymmetric C-N stretching vibration depends on the coordination mode of the thiocyanato ligand and the nature of the metal cations. The thermal properties were investigated by simultaneous differential thermoanalysis and thermogravimetry as well as temperature dependent X-ray powder diffraction. On heating compound Ni-1 looses half of the Clbp ligands and transforms into Ni-2. Clbp deficient intermediates were also detected on thermal decomposition of Mn-1 and Fe-1/I but the samples are of low crystallinity and therefore, their structures cannot be determined. Magnetic investigations reveal that Ni-2 shows only Curie-Weiss paramagnetism without any magnetic anomaly.
- Werner, Julia,Neumann, Tristan,N?ther, Christian
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- MECHANISM AND KINETICS OF THERMAL DECOMPOSITIONS OF SOLIDS GOVERNED BY PHASE BOUNDARY PROCESSES.
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Based on structural, morphological, and thermoanalytical investigations the structural reaction mechanism including topotactic relations and the respective phase boundary process controlled macroscopic reaction mechanism of the thermal decomposition of single crystalline Ni(SCN)//2(C//5H//5N)//2 to Ni(SCN)//2 is presented. From the results obtained and from the comparison with further decomposition processes of model compounds, a general approach for the evaluation of specific kinetic parameters, in particular of direction dependent rate constants of solid state decompositions governed by phase boundary processes is derived.
- Reller,Oswald
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- Synthesis and crystal structure of complexes of manganese(II), cobalt(II), and nickel(II) isothiocyanates with ε-caprolactam
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The possibility of ε-caprolactam (CPL) to coordinate to manganese(II), cobalt(II), and nickel(II) rhodanides has been investigated. New complexes trans-[M(CPL)4(NCS)2], where M = Mn (I), Co (II), and Ni (III), have been synthesized. The complexes have been studied by chemical analysis and IR spectroscopy. According to X-ray diffraction, complexes are isostructural to each other and crystallize in monoclinic space group P2 1/c3 Z = 2. For I: a = 6.9457(2) A?, b = 17.7751(6) A?, c = 12.8999(4) A?, β = 104.2670(10)°, V = 1543.51(8) A?3, Pcalc = 1.342 g/cm3, R1 = 0.0426. For II: a = 6.8925(2) A?, b = 17.8189(8) A?, c = 12.7278(6) A?, β = 104.421(2)°, V = 1513.93(11) A?3, Pcalc = 1.377 g/cm3, R1 = 0.0280. For III: a = 6.7804(2), b = 18.4631(4), c = 12.4841(3), β = 105.2950(10)°, V = 1507.49(7) 3, Pcalc = 1.382 g/cm3, R1 = 0.0273. Structures I-III are molecular; the metal atom in each of them coordinates four CPL molecules and two NCS groups via oxygen and nitrogen atoms, respectively. Pleiades Publishing, Ltd., 2012.
- Kochnev,Peresypkina,Virovets,Cherkasova
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- Coordination States of Co(NCS)2 and Ni(NCS)2 in Dimethyl Sulphoxide
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Visible absorption spectra and the molar conductance curves for Co(NCS)2 and Ni(NCS)2 have been determined at 25 deg C.The results indicate the formation of the mono-, di- and tetra-thiocyanate complexes of cobalt(II) in the Co2+-NCS-/sup
- Pilarczyk, Michal,Grzybkowski, Waclaw,Klinszporn, Lucyna
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- Synthesis, structures, and magnetic properties of new thiocyanato coordination polymers with 4-(3-phenylpropyl)pyridine as ligand
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The reaction of different metal salts with 4-(3-phenylpropyl) pyridine (ppp) lead to the formation of compounds of composition M(NCS)2(ppp)4 [M = Mn (Mn-1); Fe (Fe-1), Ni (Ni-1); Cd (Cd-1)], M(NCS)2(ppp)2(H2O)2 [M = Mn (Mn-2); Ni (Ni-2)] and [M(NCS)2(ppp)2]n [M = Mn (Mn-3); Ni (Ni-3); Cd (Cd-3)]. On heating compounds M-1 decompose without the formation of any ppp deficient intermediate. In contrast, on heating, Ni-2 transforms into a compound of composition M(NCS)2(ppp)2 that does not correspond to Ni-3. Unfortunately, this compound is of low crystallinity and therefore, its structure cannot be determined. The crystal structures of compounds M-1 and M-2 consist of discrete complexes, in which the metal cations are octahedrally coordinated. In compounds M-3 the metal cations are linked by pairs of μ-1,3-bridging anions into chains. IR spectroscopic investigations show, that the value of the asymmetric CN stretching vibration depend on the coordination mode of the anionic ligand as well as on the nature of the metal cation. Magnetic measurements reveal that Ni-3 shows only Curie-Weiss behavior without any magnetic anomaly. A similar behavior is also found for Ni-3. Comparison of the magnetic properties of Ni-3 with those of similar compounds indicates that the magnetic properties are only minor influenced by the Co-ligand.
- Werner, Julia,Jess, Inke,N?ther, Christian
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- Strengthening the Magnetic Interactions in Pseudobinary First-Row Transition Metal Thiocyanates, M(NCS)2
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Understanding the effect of chemical composition on the strength of magnetic interactions is key to the design of magnets with high operating temperatures. The magnetic divalent first-row transition metal (TM) thiocyanates are a class of chemically simple layered molecular frameworks. Here, we report two new members of the family, manganese(II) thiocyanate, Mn(NCS)2, and iron(II) thiocyanate, Fe(NCS)2. Using magnetic susceptibility measurements on these materials and on cobalt(II) thiocyanate and nickel(II) thiocyanate, Co(NCS)2 and Ni(NCS)2, respectively, we identify significantly stronger net antiferromagnetic interactions between the earlier TM ions-a decrease in the Weiss constant, θ, from 29 K for Ni(NCS)2 to-115 K for Mn(NCS)2-a consequence of more diffuse 3d orbitals, increased orbital overlap, and increasing numbers of unpaired t2g electrons. We elucidate the magnetic structures of these materials: Mn(NCS)2, Fe(NCS)2, and Co(NCS)2 order into the same antiferromagnetic commensurate ground state, while Ni(NCS)2 adopts a ground state structure consisting of ferromagnetically ordered layers stacked antiferromagnetically. We show that significantly stronger exchange interactions can be realized in these thiocyanate frameworks by using earlier TMs.
- Bassey, Euan N.,Cliffe, Matthew J.,Da Silva, Ivan,Dutton, Sian E.,Grey, Clare P.,Keyzer, Evan N.,Lee, Jeongjae,Manuel, Pascal,Paddison, Joseph A. M.
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supporting information
p. 11627 - 11639
(2020/09/09)
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- 2-Amino-4-(2-pyridyl)thiazole as chelating ligand: A dinuclear oxido-bridged ferric complex and mononuclear 3d metal complexes
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2-Amino-4-(2-pyridyl)thiazole (H2L) complexes of iron(III), iron(II), cobalt(II), nickel(II) and copper(II) have been prepared for the first time. The oxido-bridged dinuclear ferric complex [(H2L) 2FFeIII(μ-O)FeIIIF(H2L) 2](BF4)2 (1) and the mononuclear difluorido complex [FeIII(H2L)2F2](BF 4) (2) were prepared with Fe(BF4)2· 6H2O. Complex 1 contains strong antiferromagnetically coupled iron(III) ions. In addition, the mononuclear 3:1-type complex [Co(H 2L)3](ClO4)2 (3) and the mononuclear 2:1-type complexes [Cu(H2L)2](ClO4) 2 (4) and [M(H2L)2(NCX)2] (5: M = Fe, X = S; 6: M = Fe, X = Se; 7: M = Co, X = S; 8: M = Ni, X = S) were prepared. Copyright
- Huxel, Timo,Leone, Selina,Lan, Yanhua,Demeshko, Serhiy,Klingele, Julia
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p. 3114 - 3124
(2014/07/21)
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- 2-Amino-4-(2-pyridyl)thiazole as Chelating Ligand: A Dinuclear Oxido-Bridged Ferric Complex and Mononuclear 3d Metal Complexes
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2-Amino-4-(2-pyridyl)thiazole (H2L) complexes of iron(III), iron(II), cobalt(II), nickel(II) and copper(II) have been prepared for the first time. The oxido-bridged dinuclear ferric complex [(H2L)2FFeIII(μ-O)FeIIIF(H2L)2](BF4)2 (1) and the mononuclear difluorido complex [FeIII(H2L)2F2](BF4) (2) were prepared with Fe(BF4)2·6H2O. Complex 1 contains strong antiferromagnetically coupled iron(III) ions. In addition, the mononuclear 3:1-type complex [Co(H2L)3](ClO4)2 (3) and the mononuclear 2:1-type complexes [Cu(H2L)2](ClO4)2 (4) and [M(H2L)2(NCX)2] (5: M = Fe, X = S; 6: M = Fe, X = Se; 7: M = Co, X = S; 8: M = Ni, X = S) were prepared.
- Huxel, Timo,Leone, Selina,Lan, Yanhua,Demeshko, Serhiy,Klingele, Julia
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p. 3114 - 3124
(2015/04/27)
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- Synthesis and reactivity of some mixed ligand complexes of Ni(II) involving dithiocarbamates and hard bases
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A few mixed ligand complexes of the general formula, [Ni(L)(DMG)] [where L=(H5C2)2NCS2- (dedtc-), (HOH4C2)NHCS2- (meadtc-), (HOH4C2)2NCS2- (deadtc-), H10C5NCS2- (pipdtc-), oxine(OX); DMG= dimethylglyoxime] have been synthesised and characterized by elemental analysis, IR, electronic spectra and thermogravimetric analysis.
- Rajendiran,Ramalingam,Thiruneelakandan
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p. 1101 - 1103
(2007/10/03)
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- Synthesis of some 3d-Metal Complexes of 2,6-Diacetylpyridine(benzyl and acetone)hydrazone
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2,6-Diacetylpyridine bis(benzyl and acetone)hydrazone and some 3d-metal complexes have been prepared. These complexes are five-coordinated trigonal bipyramidal. The ligand coordinates through the pyridine-N and amide-N. Formation of two chelate rings by one molecule of ligand, is a feature that undoubtedly enhances the stability of the complexes.
- Singh,Ansari,Rana
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p. 448 - 451
(2007/10/03)
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- Thermal studies of 2-aminoethanol complexes of nickel (II) in the solid state
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[NiL3]X2 (where L = 2-aminoethanol and X is Cl-, Br-, I-, NO3-, 0.5SO42- or 0.5SeO42-) and [NiL2X2] (X is Cl-, Br-, or SCN-) have been synthesised from solution and their thermal study has been carried out in the solid phase. [NiL3]I2 and [NiL3]SeO4 undergo reversible endothermic phase transitions upon heating (63-93°C and 94-113°C, respectively, for heating and 94-65°C and 110-190°C, respectively, for cooling), whereas [NiL3](NO3)2 exhibits two successive reversible endothermic phase transitions (10-38°C and 50-62°C for heating and 56-48°C and 19 - (-8)°C for cooling). On the other hand, [NiL3]SO4 undergoes irreversible endothermic phase transition (99-112°C) in the solid state. All these transformations are assumed to be associated with the conformational changes of 2-aminoethanol chelate rings. [NiL2(NCS)2] melts at ~ 168°C and remains supercooled for a few days at ambient temperature. The initial temperatures of decomposition (Ti) of these complexes have been compared with those of the corresponding ethane-1, 2-diamine complexes of nickel (II).
- Das, Debasis,Ghosh, Ashutosh,Koner, Subratanath,Ray Chaudhuri, Nirmalendu
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- Preparation, characterisation and thermal behaviour of N-(3-aminopropyl)-1,3-propanediamine complexes of nickel(II) in the solid state
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The complexes [Ni(dpt)2]X2.nH2O (where dpt is N-(3-aminopropyl)1,3-propanediamine; n = 0 when X is I, NCS or ClO4; n = 1 when X is Cl, Br or NO3; n = .mchgt. 1 when X is 0.5SO4 and 0.5SeO4), Ni(dpt)X2.nH2O (n = 0 when X is Cl or NO3; n = 1 when X is Br or
- Pariya, Chandi,Ghosh, Ashutosh,Chaudhuri, Nirmalendu Ray
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p. 199 - 210
(2008/10/09)
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- Comparative study of tetrametallic complexes of bis(selenocyanatomercurio)-ferrocene and their thiocyanato analogues
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Cu(Salen) and Zn(Salen) have been reacted with Fe(C5H4HgSeCN)2M(NCS)2 and adducts have been prepared.A comparative study with their thiocyanato analogues indicates that there is no basic difference between the structure of the thiocyanato and selenocyanato complexes; however, they differ in stability, solubility, conductance and electronic spectral parameters.
- Singh, P. P.,Gupta, D. S.,Singh, A. P.
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p. 476 - 480
(2007/10/02)
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- Studies on tetrametallic complexes of 1, 1'-bis(thiocyanatomercurio)ferrocene
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Cu(Salen) and Zn(Salen) have been reacted with Fe(C5H4HgSCN)2M(NCS)2 and adducts having four different metals have been prepared.The various physicochemical studies indicate that Cu(Salen) and Zn(Salen) act as bidentate ligands coordinating through phenolic oxygen.The geometry, where M is Co(II), Mn(II), Zn(II), changes from tetrahedral in the Lewis acids to octahedral in adducts.
- Singh, P. P.,Singh, Deepa,Singh, A. P.
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p. 472 - 475
(2007/10/02)
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- Bimetallic Complexes involving Schiff Base
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Phenylmercury derivative (phHgSA) of Schiff base SAH derived from salicylaldehyde and aniline have been prepared.Reaction of this derivative with M(NCS)2, where M=CoII, NiII, CuII and ZnII, gave complexes of general formula (phHgSA)2M(NCS)2.These complexes on further reaction pyridine or bipyridine (L) furnished adducts of general formula (phHgSA)2M(NCS)2Lx, where x=1 or 2.All the complexes have been characterised by elemental analysis, molecular weight, molar conductance, infrared and electronic spectral data.On the basis of these studies, probable structure of the complexes and quantitative softness parameters have been evaluated.
- Singh, P. P.,Srivastava, Beena
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p. 797 - 800
(2007/10/02)
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- Cobalt(II), Nickel(II) and Copper(II) Complexes with Neutral and Deprotonated 1-Hydroxymethyl-3,5-dimethylpyrazole
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Cobalt(II), nickel(II) and copper(II) complexes of 1-hydroxymethyl-3,5-dimethylpyrazole (DMPzCH) and its deprotonated anion (DMPzC) have been isolated and characterised in the solid state.Magnetic and electronic spectral data indicate that the stereochemistry of Co(DMPzCH)X2.nH2O is dependent on the counterion, the halo and thiocyanato species.Co(DMPzCH)X2 being tetrahedral both in solid and in solution while the corresponding nitrate, perchlorate and sulphate comlexes are pseudo-octahedral.All the mono chelates of Ni(II) and Cu(II) of general composition M(DMPzCH)X2.nH2O (X = Cl, Br, I, ClO4, NO3, 0.5SO4, SCN) as well as bis-species M(DMPzC)2.2H2O are octahedral, the anion in the mono-species being prefentially coordinated as evidenced by IR data.The pyrazolyl ring nitrogen and the carbinol oxygen of the ligand appear to be the bonding sites during complex formation.The neutral bidentate (N-O) and monoprotic bidentate (N-O) character is envisaged in the mono- and the bis-species respectively.
- Saha, Nityananda,Adak, Asok K.
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p. 499 - 502
(2007/10/02)
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- Studies on (XCN)2M(NCS)2Hg2(p-tolyl)2 and (XCN)2M(NCS)2Hg2-(α-naphthyl)2 and Their Complexes with Pyridine, Dimethyl Sulphoxide and 2,2'-Bipyridyl
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Bimetallic compounds of the formula (XCN)2M(NCS)2Hg2R2 and their complexes with pyridine (Py), dimethyl sulphoxide (DMSO) and 2,2'-bipyridyl (bipy) have been prepared and characterised by elemental analyses, molar conductance, molecular weight, magnetic moment, infrared and electronic spectral studies.These studies reveal that (XCN)2M(NCS)2Hg2R2 and their Py and DMSO adducts are monomeric while the 2,2'-bipyridyl complexes are cationic-anionic.The stereochemistry around Co(II) and Ni(II) ions is octahedral in all their compounds except in the case of (XCN)2MCo(NCS)2Hg2R2 where it is tetrahedral.
- Singh, P. P.,Atreya, Kshipra,Yadava, S. P.
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p. 376 - 381
(2007/10/02)
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- Diisothiocyanatodihalonickelates(II)
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Few diisothiocyanatodihalonickelates(II) R2 have been isolated from non-aqueous media and characterized by chemical analyses, melting points, molar conductance, ir and far ir and electronic spectral studies.
- Prasad, R. S.,Kumari, Amrita,Jha, N. K.
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p. 207 - 209
(2007/10/02)
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- Bidentate group vb ligands. Part XIII. Divalent cobalt, nickel, and palladium complexes of 1,2-bis(methylphenylarsino)ethane and 1,3-bis(methylphenylarsino)propane. Stoichiometric and structural effects of chelate chain length
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Thirtyfour complexes of 1,2-bis(methylphenylarisino)ethane (dase) and 1,3-bis(methylphenylarsino)propane (dasp) have been characterised. Interesting differences are observed in the complexing properties of these chelates. Thus, with cobalt(II) halides [Co(dase)2][CoX4], which contain planar cations, and pseudotetrahedral [Co(dasp)X2] are obtained. Nickel (II) halides form planar [NiLX2] complexes with dase, but with dasp form [Ni(dasp)X2]n (X = Cl, Br) which are pseudooctahedral in the solid state and planar in solution, and the pseudotetrahedral [Ni(dasp)I2]. The [Ni(dasp)2X] ClO4 are trigonal bipyramidal in the solid state (X = Cl, Br, I, NCS), but in solution [Ni(dasp)2(NCS)]+ appears to be square pyramidal, whilst the [Ni(dase)2X] ClO4 are square pyramidal in both the solid state and solution. The planar [Ni(dasp)(NCS)2] complex differs from the analogous dase species by losing ligand on recrystallisation to form the dimeric Ni2(dasp)3(NCS)4moiety. Planar [PdLX2] (L = dase, dasp, X = Cl, Br, I) species are formed, but no [PdL2X]+ complexescould be isolated. In the solid state [PdL(NCS)(SCN)] complexes are formed, and the dase species isomerises to [Pd(dase)(SCN)2] in dichloromethane. An attempt is made to relate the structural differences in the complexes to the chain length of the chelates.
- Levason,McAuliffe,Murray
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