3017-60-5Relevant articles and documents
Neutron diffraction study of quasi-1D Ising ferromagnet [Co(NCS)2(pyridine)2]n
Baran, Stanis?aw,Hoser, Andreas,Rams, Micha?,Ostrovsky, Serghei,Neumann, Tristan,N?ther, Christian,Tomkowicz, Zbigniew
, p. 290 - 297 (2019)
The quasi-one-dimensional [Co(NCS)2(pyridine)2]n coordination polymer built of ferromagnetic chains of Co(II) ions linked by (NCS)2 anions is known as an Ising ferromagnet that magnetically orders at TC = 3.9 K. We performed a neutron diffraction study and show that the magnetic structure is collinear ferromagnetic, static, and without any glassy component. The magnitude of the ordered magnetic moment of Co(II) is 3.65(15) μB, which points to a relatively large contribution of the orbital moment. The direction of the moment is close to the direction of the Co–N(pyridine) bond, which confirms literature ab initio calculations. We show that dipolar interactions are mainly responsible for the magnetic interchain coupling.
Mohapatra, M.,Chakravortty, V.,Dash, K. C.
, p. 1509 - 1516 (1989)
Solid-state transformation of [Co(NCS)2(pyridine)4] into [Co(NCS)2(pyridine)2]n: From Curie-Weiss paramagnetism to single chain magnetic behaviour
Boeckmann, Jan,Naether, Christian
, p. 11019 - 11026 (2010)
Reaction of Co(NCS)2 with pyridine (pyr) in aqueous solution at room temperature leads to the formation of the pyridine-rich 1:4 compound of composition [Co(NCS)2(pyridine)4] (1) reported recently. On heating, the pyridine-rich 1:4 compound transforms into its corresponding pyridine-deficient 1:2 compound of composition [Co(NCS)2(pyridine) 2]n (2), which decomposes on further heating. In the crystal structure of compound 2 the metal cations are coordinated by four N-atoms of two pyridine ligands and two N-bonded thiocyanato anions, each in mutually trans orientation, and by two S-atoms of two adjacent thiocyanato anions in a slightly distorted octahedral geometry. The thiocyanato anions bridge the metal cations forming one-dimensional polymeric chains. IR spectroscopic investigations on the pyridine-deficient 1:2 compound prepared in thermal decomposition are in accordance with bridging thiocyanato anions. Magnetic measurements of the pyridine-rich 1:4 compound and pyridine-deficient 1:2 compound reveal different behaviour with Curie-Weiss paramagnetism for compound 1 and single chain magnetic behaviour for compound 2, with a Mydosh-parameter φ = 0.12 and an effective energy barrier (-U eff/kB) of 62.5 K for the spin relaxation. The Royal Society of Chemistry 2010.
Ionization Equilibria in Solutions of Cobalt(II) Thiocyanate in N,N-Dimethylformamide
Pilarczyk, Michal,Grzybkowski, Waclaw,Klinszporn, Lucyna
, (1987)
Visible absorption spectra and molar conductance curve for Co(NCS)2 in N,N-dimethylformamide (DMF), together with the spectra for the Co(ClO4)2-KNCS-DMF, Co(NCS)2-KNCS-DMF and Co(NCS)2-DMF-chlorobenzene systems, have been determined at 25 deg C.The result
A novel paramagnetic coordination polymer, fabricated from Co(NCS)2 and 2-pyridinecarbaldehyde isonicotinoylhydrazone
Ay, Burak,Mahmoudi, Ghodrat,Akbar Khandar, Ali,Akbari Afkhami, Farhad,Toprak, Atakan,Zubkov, Fedor I.,White, Jonathan,K?ak, Julia,Safin, Damir A.
, (2021)
We report on a mixed cobalt(II)/cobalt(III) heteroleptic coordination polymer of the salt-like structure {[(CoIIIL2)2CoII(NCS)2][CoII(NCS)4]}n?a(solvent) (1?a(solvent)), obtained by a reaction of Co(NCS)2 with 2-pyridinecarbaldehyde isonicotinoylhydrazone (HL). Complex 1?a(solvent) contains 15.52% of solvent molecules, which fits to six molecules of EtOH per one [(CoIIIL2)2CoII(NCS)2][CoII(NCS)4] species, and the structure of the crystals can be assigned to the {[(CoIIIL2)2CoII(NCS)2][CoII(NCS)4]}n?6EtOH composition. 1?a(solvent) was found to be stable after drying at 80 °C for several days, yielding a solvent-free complex 1. The FTIR data of both structures supports the complete loss of solvents after drying, while the general framework remains intact. As evident from the comparison of the experimental X-ray powder diffraction data of 1 with the calculated powder pattern generated from the single crystal X-ray data of 1?a(solvent), the former complex partially loses its crystallinity; however, the experimental powder pattern resembles the calculated one. Thus, the overall structure of 1 is similar to that of 1?a(solvent). The crystal structure of 1?a(solvent) is constructed from the V-shaped (CoIIIL2)+ cations, where the metal ion is N4S2-coordinated by two L. These (CoIIIL2)+ cations are interlinked through CoII(NCS)2 molecules by coordination via free 4-pyridyl nitrogen atoms, yielding a 1D polymeric cationic chain {[(CoIIIL2)2CoII(NCS)2]2+}n, which are interlinked into a 3D framework through a bunch of bifurcated (N)C–S?π(2-Py) and linear (NN)C–H?O non-covalent interactions. Due to such 3D aggregation, a half of rhombohedral cells are filled by the interlayered [CoII(NCS)4]2– anions, while the other half of cells is free from non-volatile species and filled with volatile solvent molecules, yielding 1D tubular voids, which occupy about 17% of unit cell volume. Direct current variable-temperature magnetic susceptibility measurements on a polycrystalline sample of 1?a(solvent) were carried out in the temperature range 1.8–300 K. The magnetic behaviour of 1?a(solvent) indicates the presence of magnetic anisotropy of the CoII ions and/or very weak intermolecular exchange interactions. The surface and pore properties of 1 and HL were calculated by N2 adsorption at 77 K. In addition, CO2 adsorption properties of 1 and HL at different temperatures were determined. It was found that 1 increased both textural and CO2 adsorption properties.
Strengthening the Magnetic Interactions in Pseudobinary First-Row Transition Metal Thiocyanates, M(NCS)2
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.
supporting information, p. 11627 - 11639 (2020/09/09)
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.
