Search results for "cobalt."

Preparation of dithiacycloalkynes by cyclization reactions applying the cesium effect

1993

Abstract The strained dithiacycloalkynes 3a,b and the larger heterocyclic alkynes 3c and 4 are obtained by cesium assisted cyclization reactions of the dithiols 1a–c and 1,4-dibromo-2-butyne (2). The reactivity of 3a–c was studied in cycloaddition and complexation reactions generating the adducts 5a,b and 6 and the silver and cobalt complexes 7 and 8.

Magnetic phase transition and magnetic bistability in oxamato-based CoIICuII bimetallic MOF thin films

2019

Abstract Thin films of an anionic oxamato-bridged cobalt(II)–copper(II) 3D MOF have been growth at 120 °C in DMSO through a one-pot reaction from Co(NO3)2·6H2O and (Me4N)2[Cu(2,6-Et2pa)2]·6H2O (2,6-Et2pa = N-2,6-diethylphenyloxamate) over Si(111) surfaces functionalized with carboxylic acid terminating groups. These heterobimetallic CoII2CuII3 MOF thin films (2) of about ten nanometers thickness show a ferrimagnetically ordered phase below ca. 10 K with a relatively large magnetic hysteresis similar to that of the bulk material of formula (Me4N)2[Co2Cu3(2,6-Et2pa)6]·5H2O (1).

Studies on coordination compounds—VIII. Syntheses, structural, magnetic, spectral and thermal properties of some cobalt(II), nickel(II) and copper(II…

1995

Abstract The complexes bis[triaqua(2-aminopyrimidine)-μ-sulphato-O,O′-cobalt(II)] dihydrate (1), catena-[diaqua(2(2-aminopyrimidine))-μ-sulphato-O,O′nickel(II)]2-amino-pyrimidine (2), [pentaaqua(2-aminopyrimidine)nickel(II)]sulphate 2-aminopyrimidine (3) and catena-[aqua(2(2-aminopyrimidine))-μ-sulphato-O,O′-copper(II)] dihydrate (4) were prepared, structure determined by X-ray methods and physical properties studied by magnetic, IR, NMR, EPR and reflectance methods. The thermal behaviour was studied by TG and mass spectrometric methods. The results are discussed on a structural basis.

Cobalt−NHC Catalyzed C(sp 2 )−C(sp 3 ) and C(sp 2 )−C(sp 2 ) Kumada Cross‐Coupling of Aryl Tosylates with Alkyl and Aryl Grignard Reagents

2020

Cobalt(II), nickel(II) and copper(II) complexes withN-cyano-N?-methyl-N?(2-[(5-methyl-1H-imidazol-4-yl)methylthio]ethyl)guanidine

1985

N-Cyano-N′-methyl-N″(2-[(5-methyl-1H-imidazol-4-yl)-methylthio] ethyl) guanidine cimetidine (CM), complexes with CoII, NiII and CuII are described. The compounds are of stoichiometry [M(CM)2]SO4 · nH2O [M = CoII, NiII or CuII; n = 3,3 or 4, respectively], [M(CM)2](ClO4)2 [M = CoII or NiII], [M(CM)2]Cl2 · nH2O [M=CoII, NiII or CuII; n = 1, 2, or 2, respectively] and [Cu(CM)SO4] · 2H2O. The electronic spectra of the compounds in solid state, magnetic susceptibilities and i.r. and e.p.r. spectra were studied. Octahedral environments are proposed for the complexes: [M(CM)2]SO4·nH2O, [M(CM)2](ClO4)2, [Ni(CM)2]Cl2 · 2H2O, [Cu(CM)2]Cl2 · 2H2O and [Cu(CM)SO4] · 2H2O and a tetrahedral structure for …

Solid-state dinuclear-to-trinuclear conversion in an oxalato-bridged chromium(III)-cobalt(II) complex as a new route toward single-molecule magnets.

2011

A novel bis(oxalato)chromium(III) salt of a ferromagnetically coupled, oxalato-bridged dinuclear chromium(III)-cobalt(II) complex of formula [CrL(ox)(2)CoL'(H(2)O)(2)][CrL(ox)(2)]·4H(2)O (1) has been self-assembled in solution using different aromatic α,α'-diimines as blocking ligands, such as 2,2'-bipyridine (L = bpy) and 2,9-dimethyl-1,10-phenanthroline (L' = Me(2)phen). Thermal dehydration of 1 leads to an intriguing solid-state reaction between the S = 3/2 Cr(III) anions and the S = 3 Cr(III)Co(II) cations to give a ferromagnetically coupled, oxalato-bridged trinuclear chromium(III)-cobalt(II) complex of formula {[CrL(ox)(2)](2)CoL'} (2). Complex 2 possesses a moderately anisotropic S =…

Coordination chemistry of sulfamethizole: crystal structures of [Cu(sulfamethizolate)2(py)2(OH2)]·H2O, [M(sulfamethizolate)2(py)2(OH2)2] [M=Co and Ni…

2000

Abstract The synthesis and characterisation of copper, cobalt, nickel and zinc compounds with sulfamethizole (4-amino-N-(5-methyl-1,3,4-thiadiazole-2-yl)sulfanilamide) (Hsmtz) are described. The first crystal structures of ternary sulfamethizole complexes are reported. The crystal structures of Cu(smtz)2(py)2(OH2)·H2O (1), M(smtz)2(py)2(OH2)2 [M=Co (2), Ni (3)] and {Cu(smtz)2(dmf)2}∞ (5) were determined by X-ray diffraction. The Cu(II) ion exhibits a square pyramidal geometry in complex 1, while in the other compounds the metal ion presents a distorted octahedral environment. In compounds 1, 2 and 3 the deprotonated sulfamethizole acts as monodentate ligand coordinating through the thiadiaz…

Effects of halogen bonding in ferromagnetic chains based on Co(ii) coordination polymers

2010

Two linear cobalt chloride ferromagnetic chains, trans-[CoCl2(3,5-X2py)2] [X = Cl (1), Br (2)], have been prepared and the influence of the halogen bonding on the interchain magnetic interactions has been investigated.

Structural characterization of frozen n-heptane solutions of metal-containing reverse micelles

2007

The microstructure of temperature-quenched solutions of reverse micelles formed by sodium, cobalt, ytterbium, and cobalt/ytterbium bis(2-ethylhexyl)sulfosuccinate in n-heptane has been investigated by SAXS and EXAFS. Some changes in the X-ray absorption spectra with respect to the same systems at room temperature have been observed. The analysis of the SAXS spectra leads to the hypothesis that at 77 K the closed spherical structure of reverse micelles is retained and that during the temperature quench they undergo a clustering process involving the transition from a quite random dispersion to the formation of more or less large clusters of strongly packed reverse micelles. This behavior is …

Experimental and theoretical investigations of the redox behavior of the heterodichalcogenido ligands [(EP(i)Pr2)(TeP(i)Pr2)N](-) (E = S, Se): cyclic…

2008

The two-electron oxidation of the lithium salts of the heterodichalcogenidoimidodiphosphinate anions [(EP (i)Pr 2)(TeP (i)Pr 2)N] (-) ( 1a, E = S; 1b, E = Se) with iodine yields cyclic cations [(EP (i)Pr 2)(TeP (i)Pr 2)N] (+) as their iodide salts [(SP (i)Pr 2)(TeP (i)Pr 2)N]I ( 2a) and [(SeP (i)Pr 2)(TeP (i)Pr 2)N]I ( 2b). The five-membered rings in 2a and 2b both display an elongated E-Te bond as a consequence of an interaction between tellurium and the iodide anion. One-electron reduction of 2a and 2b with cobaltocene produces the neutral dimers (EP (i)Pr 2NP (i)Pr 2Te-) 2 ( 3a, E = S; 3b, E = Se), which are connected exclusively through a Te-Te bond. Two-electron reduction of 2a and 2b …