- Neutron diffraction study of quasi-1D Ising ferromagnet [Co(NCS)2(pyridine)2]n
-
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.
- Baran, Stanis?aw,Hoser, Andreas,Rams, Micha?,Ostrovsky, Serghei,Neumann, Tristan,N?ther, Christian,Tomkowicz, Zbigniew
-
-
Read Online
- 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
-
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.
- Boeckmann, Jan,Naether, Christian
-
-
Read Online
- Ionization Equilibria in Solutions of Cobalt(II) Thiocyanate in N,N-Dimethylformamide
-
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
- Pilarczyk, Michal,Grzybkowski, Waclaw,Klinszporn, Lucyna
-
-
Read Online
- Stereochemistry of coordination polyhedra: Vs. single ion magnetism in penta- And hexacoordinated Co(ii) complexes with tridentate rigid ligands
-
A tridentate ligand L (2,6-bis(1-(3,5-di-tert-butylbenzyl)-1H-benzimidazol-2-yl)pyridine) was synthesized and used for the preparation of three pentacoordinated Co(ii) complexes of formula [Co(L)X2] (where X = NCS- for 1, X = Cl- for 2 and X = Br- for 3) and one ionic compound 4 ([Co(L)2]Br2·2CH3OH·H2O) containing a hexacoordinated Co(ii) centre. Static magnetic data were analysed with respect to the spin (1-3) or the Griffith-Figgis (4) Hamiltonian. Ab initio calculations enable us to identify the positive axial magnetic anisotropy parameter D accompanied by a significant degree of rhombicity in the reported complexes. Also, magneto-structural correlation was outlined for this class of compounds. Moreover, all four compounds exhibit slow relaxation of magnetisation at an applied static magnetic field with either both low- and high-frequency relaxation channels (3) or a single high-frequency relaxation process (1, 2 and 4). The interplay between the stereochemistry of coordination polyhedra, magnetic anisotropy and the relaxation processes was investigated and discussed in detail.
- Brachňaková, Barbora,Matejová, Simona,Moncol, Ján,Herchel, Radovan,Pavlik, Ján,Moreno-Pineda, Eufemio,Ruben, Mario,?alitro?, Ivan
-
-
Read Online
- A novel paramagnetic coordination polymer, fabricated from Co(NCS)2 and 2-pyridinecarbaldehyde isonicotinoylhydrazone
-
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.
- Ay, Burak,Mahmoudi, Ghodrat,Akbar Khandar, Ali,Akbari Afkhami, Farhad,Toprak, Atakan,Zubkov, Fedor I.,White, Jonathan,K?ak, Julia,Safin, Damir A.
-
-
Read Online
- Coordination-driven self-assembly of a series of dinuclear M2L2mesocates with a bis-bidentate pyridylimine ligand
-
Four isostructural dinuclear M2L2mesocates of the general formula [M2(NCS)4(L)2]·4.5MeOH (1M; M = Mn, Fe, Co, Zn) were constructed by using the coordination-driven self-assembly of the [M(NCS)2] precursor and the flexible bis-bidentate pyridylimine Schiff base ligand L (L = 4,4′-(1,4-phenylenebis(oxy))bis(N-(pyridin-2-ylmethylene)aniline). The centrosymmetric M2L2mesocate forms through the side-by-side coordination of two L ligands to a pair of M(ii) ions. The mesocates exhibit a reversible temperature induced desolvation-solvation behavior without losing their structural integrity. The activated1Co, as the representative M2L2mesocate, shows an exceptionally high MeOH vapour uptake capacity of 481.9 cm3g?1(68.8 wt%) at STP with good recyclability. Notably, it also exhibits CO2adsorption with an uptake capacity of 20.2 cm3g?1(3.6 wt%) at room temperature and 1 bar.
- Chainok, Kittipong,Dungkaew, Winya,Jiajaroen, Suwadee,Jittirattanakun, Siripak,Kielar, Filip,Puangsing, Praifon,Rungtaweevoranit, Bunyarat,Saphu, Watcharin,Sukwattanasinitt, Mongkol,Theppitak, Chatphorn
-
p. 7736 - 7743
(2021/06/16)
-
- Strengthening the Magnetic Interactions in Pseudobinary First-Row Transition Metal Thiocyanates, M(NCS)2
-
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.
-
supporting information
p. 11627 - 11639
(2020/09/09)
-
- A tetracoordinate Co(II) single molecule magnet based on triphenylphosphine and isothiocyanato group
-
A simple Co(II) mononuclear complex [Co(PPh3)2(NCS)2] has been studied in details. Its crystal and molecular structure is reported along with its IR a UV–Vis spectra. The DC magnetization studies confirm a sizable zero-field splitting D/hc?=??9.4?cm?1that is also confirmed by quantum-chemical calculations. The AC susceptibility data shows that there is a slow magnetic relaxation with two relaxation branches. The low-frequency branch occurs at about f?=?1–10?Hz and it tends to disappear progressively on heating. The high-frequency branch exists at the frequency ranges above f?>?200?Hz and this is shifted above the hardware limit (1500?Hz) on heating. The characteristics of this field-induced single molecule magnet strongly depend upon the applied DC field (0.2–0.4?T).
- Rajnák, Cyril,Packová, Alena,Titi?, Ján,Miklovi?, Jozef,Moncol, Ján,Bo?a, Roman
-
-
- Proton reduction using cobalt glyoximes with isothiocyanate and aniline axial ligands
-
Cobaloxime model complexes containing aniline derivatives and isothiocyanate as the axial ligands Co(dmgH)2XY (dmgH = dimethylglyoxime, X = NCS, Cl and Y = aniline, pyridine) have been synthesized and used as proton reduction catalysts. Using acetic acid as the proton source in acetonitrile, cyclic voltammetry studies have shown that these complexes are comparable to the well-known Co(dmgH)2(pyridine)Cl complex as a potent catalyst in terms of the overpotential and catalytic efficiency of proton reduction. In particular, we have shown that aniline derivatives can be used as possible pyridine alternatives in cobaloximes in our continuing search for an even more efficient proton reduction catalyst.
- Fan, Wai Yip,Tan, Zi Bin,Koh, Jingzhi Iris
-
-
- 2-Amino-4-(2-pyridyl)thiazole as Chelating Ligand: A Dinuclear Oxido-Bridged Ferric Complex and Mononuclear 3d Metal Complexes
-
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
-
p. 3114 - 3124
(2015/04/27)
-
- 2-Amino-4-(2-pyridyl)thiazole as chelating ligand: A dinuclear oxido-bridged ferric complex and mononuclear 3d metal complexes
-
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
-
p. 3114 - 3124
(2014/07/21)
-
- Synthesis and crystal structure of complexes of manganese(II), cobalt(II), and nickel(II) isothiocyanates with ε-caprolactam
-
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
-
p. 1067 - 1072
(2012/09/21)
-
- Synthesis, characterization and spectral studies of cobalt(II) complexes of ethyl and t-butyl esters of hydrazine carboxylic acid
-
Cobalt(II) complexes of the general compositions, [CoL2X 2] (L = NH2NHCOOR; R = Et or But; X = Cl -, Br-, I-, NO3- and NCS-) have been synthesized and characterized by elemental analysis, molar conductance, spectroscopic techniques (UV-Vis, IR) and magnetic moment measurements. The low conductivity data of all the complexes suggest their non-electrolytic nature. The magnetic studies show the complexes to be high spin octahedral. On the basis of electronic spectral studies they are assigned tetragonally distorted octahedral stereochemistry. Various ligand field parameters have been evaluated.
- Jain, Prakash Chand,Singh, Netra Pal,Pahwa, Suresh Chand
-
p. 275 - 279
(2012/11/07)
-
- Synthesis, spectral studies of cobalt(II) tetrathiocyanoto dicuperate(I) complexes with some acylhydrazones and their antimicrobial activity
-
Cobalt(II) complexes of the type Co[Cu(NCS)2]2 ? L, where L is acetophenonebenzoylhydrazone (Abh), acetophenoneisonicotinoylhydrazone (Ainh), acetophenonesalicyloylhydrazone (Ash), acetophenoneanthraniloylhydrazone (Aah), p- hydroxyacetophenonebenzoylhydrazone (Phabh), p- hydroxyacetophenoneisonicotinoylhydrazone (Phainh), p- hydroxyacetophenonesalicyloylhydrazone (Phash), and p- hydroxyacetophenoneanthraniloylhydrazone (Phaah) were synthesized and characterized by elemental analyses, molar conductance, magnetic moments, electronic and IR spectra, and X-ray diffraction studies. The complexes are insoluble in common organic solvents and are non-electrolytes. These complexes are coordinated through the >C=O and >C=N groups of the hydrazone ligands. The magnetic moments and electronic spectra suggest a spin-free octahedral geometry around Co(II). The X-ray diffraction parameters (a, b, c) for Co[Cu(SCN)2]2 ? Ainh and Co[Cu(SCN)2] 2 ? Phabh correspond to orthorhombic and tetragonal crystal lattices, respectively. The complexes show a fair antifungal and antibacterial activity against a number of fungi and bacteria. The activity increases with increasing concentration of the compounds.
- Singh,Singh
-
p. 374 - 381
(2009/02/01)
-
- Synthesis and characterization of cobalt (II) complexes of chromen-2-one-3-carboxy hydrazide and 2-(chromen-2′-onyl)-5-(aryl) 1,3,4-oxadiazole derivatives
-
Cobalt(II) complexes of chromen-2-one-3-carboxy hydrazide and 2-(chromen 2′-onyl)-5-(aryl)-1,3,4-oxadiazole derivatives have been synthesized and characterized by elemental analysis, magnetic susceptibility, molar conductance, spectral studies [IR, UV-vis, and 1H NMR]. All the Co(II) complexes exhibit the composition M(Ln)2X2; where M = Co(II), L1 is chromen-2-one-3-carboxy hydrazide, L2 is 2-(chromen-2′-onyl)-5-(2″- hydroxylphenyl)1,3,4-oxadiazole, L3 2-(chromen-2′-onyl)-5-(4″- nitrophenyl)1,3,4-oxadiazole and L4 is 2-(chromen-2′-onyl)-5-(4″- chlorophenyl)1,3,4-oxadiazole. X = Cl-, Br-, NO 3-, CH3COO- , ClO4 -, CNS-, SO4-. The N,O donor ligands act as a bidentate ligand in all the complexes. Distorted octahedral geometry for all the Co(II) complexes is proposed. X-ray structure determination has been made for the exact definition of the coordination sphere. The newly synthesized Co(II) complexes have been screened for their antimicrobial activity against some bacterial species like E. coli, S. aureus, Pseudomonas aeruginosa and few fungal strains, C. albicans and Cryptococcus neoformans.
- Mathew, Glory,Suseelan,Krishnan
-
p. 2040 - 2044
(2007/10/03)
-
- Large-ring chain and sheet polymeric metal complexes of extended-reach siloxypyridine ligands of type O[iPr2SiO(CH2)npy]2
-
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.
-
-
- Synthesis and spectral properties of cobalt(III) complexes containing SCN dimethylglyoxime and heterocyclic N-donor ligands
-
Different nitrogen donor ligands (pyridine, piperidine, quinoline, iso-quinoline, triazole, indole, benzimidazole, benzotriazole, carbazole) react with Co(SCN)2 and dimethylglyoxime (DH2) in ethanolic medium in presence of air to form a number of new Co(III) complexes of the type trans-[Co(DH)2(L)(SCN)], which are characterised on the basis of electronic and IR spectra NMR, (1H and 13C) spectra, thermogravimetric (TG-DT) analysis and conductance measurements. The thiocyanate group is S-bonded. The NMR observation suggests that in solution, these compounds exist as mixtures of neutral species [Co(DH)2(L)(SCN)] and the salt [Co(DH)2(SCN)2]. TG and DT analysis show that these complexes proceed through polymeric intermediate, and give Co3O4 as the end product.
- Nayak,Sahoo,Das
-
p. 537 - 539
(2007/10/03)
-
- Synthesis of some 3d-Metal Complexes of 2,6-Diacetylpyridine(benzyl and acetone)hydrazone
-
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
-
p. 448 - 451
(2007/10/03)
-
- Synthesis and characterization of some neutral amphipathic cobaloxime complexes
-
A number of mixed ligand complexes of the type trans-[Co(DH)2(AM)X] where DH = dimethylglyoxime, AM = dodecylamine or butylamine and X = Cl-, I-, N-3, NO-2 and SCN- have been synthesised and characterized. The electronic absorption spectra, IR and NMR (1H and 13C) spectra indicate the trans-configuration for the isolated complexes.
- Arumugam,Arunachalam
-
p. 315 - 316
(2007/10/03)
-
- Comparative study of tetrametallic complexes of bis(selenocyanatomercurio)-ferrocene and their thiocyanato analogues
-
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.
-
p. 476 - 480
(2007/10/02)
-
- Studies on tetrametallic complexes of 1, 1'-bis(thiocyanatomercurio)ferrocene
-
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.
-
p. 472 - 475
(2007/10/02)
-
- Coordination States of Co(NCS)2 and Ni(NCS)2 in Dimethyl Sulphoxide
-
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
-
p. 3395 - 3402
(2007/10/02)
-
- Calorimetric study of thiocyanato complexes of the cobalt(II) ion in micellar solutions of a nonionic surfactant
-
Complex formation equilibria between cobalt(II) and thiocyanate ions have been studied calorimetrically in an aqueous solution and in micellar solutions of the nonionic surfactant Triton X-100 containing MClO4 (M = Li, Na, NH4) as ionic media at 25 °C. Calorimetric data were well explained in terms of the formation of [Co(NCS)]+ and [Co(NCS)2] and of [Co(NCS)]+, [Co(NCS)2], and [Co(NCS)4]2- in water and in micellar solutions, respectively. The formation of [Co(NCS)3]- was found to be practically negligible in any of the solutions examined. The formation constant and enthalpy of formation of [Co(NCS)4]2- change with the concentration of the surfactant and with the ionic media in the micellar solutions, while those of [Co(NCS)]+ remain practically constant. It is suggested that the [Co(NCS)]+ complex is formed only in the aqueous phase, while [Co(NCS)4]2- is formed mainly in micelles as ion pairs.
- Ishiguro, Shin-Ichi,Sotobayashi, Takeshi,Satoh, Keiichi,Saito, Kazuo
-
p. 1152 - 1155
(2008/10/08)
-
- Bimetallic Complexes involving Schiff Base
-
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
-
p. 797 - 800
(2007/10/02)
-
- 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
-
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.
-
p. 376 - 381
(2007/10/02)
-
- Cobalt(II), Nickel(II) and Copper(II) Complexes with Neutral and Deprotonated 1-Hydroxymethyl-3,5-dimethylpyrazole
-
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.
-
p. 499 - 502
(2007/10/02)
-