Structure,spectroscopic, and magnetic properties of a new cobalt(II) complex with 5-sulfoisophthalic anion

A complex of [Co(H₂SIP)(Phen)(H₂O)₃] ? H₂O (H₂SIP = 5-sulfoisophthalic anion, Phen = 1,10-phenanthroline) has been synthesized by hydrothermal reaction. Crystal structure determination revealed that the complex crystallizes in the monoclinic space group P2(1)/c, in which Co(II) is distorted octahedral coordinating with one carboxylate sulfonate ligand, one phen, and three coordinated waters. Molecules of [Co(H₂SIP)(Phen)(H₂O)₃] ? H₂O are connected to form a 3-D structure by intermolecular hydrogen bonds and π–π stacking interactions. IR spectra, UV-Vis spectra, and magnetic susceptibilities have been analyzed to obtain values of the ligand field and magnetic parameters: Α = 1.33, λ = ?102.3 cm^?1, κ = 0.96, and Δ = 252.2 cm^?1.     

Synthesis,characterization, and crystal structure of cobalt(II) complex with 2-oximino-3-thiosemicarbazone-2,3-butanedione

The reaction of cobalt(II) chloride with the tridentate ligand 2-oximino-3-thiosemicarbazone-2,3-butanedione [Hotsb (1)] leads to the formation of the novel six-coordinated complex [Co(otsb)₂]·2H₂O (2). This complex has been synthesized and characterized by X-ray crystallography, spectroscopic and cyclic voltammetric measurements. The ligand Hotsb (1) obtained by the condensation of 2,3-butanedione monoxime and thiosemicarbazide is used for the preparation of complex 2. The Hotsb (1) crystallizes into a monoclinic lattice with space group P2₁/c. The crystal structure of 2 shows a distorted mer-octahedral geometry in which the ligands are coordinated as uninegatively charged tridentate chelating agents via the hydrazine nitrogen atoms, the azomethine nitrogen atoms, and the thiolate sulfur atoms. The cyclic voltammogram of 2 undergoes two irreversible one-electron waves corresponding to Co^II/Co^III and Co^II/Co^I processes.     

Dynamic helicity inversion by achiral anion stimulus in synthetic labile cobalt(II) complex

The helical chirality of a Co(II) complex with a chiral tetradentate ligand is completely inverted from Lambda to Delta by the addition of achiral NO3- anion as an external stimulus.     

Synthesis and spectroscopic studies of the cobalt(II) complex with methyl 2-pyridylmethylidenehydrazinecarbodithioate (HNNS)

A new cobalt(II) complex with the Schiff base methyl 2-pyridylmethylidenehydrazinecarbodithioate (HNNS), Co(NNS)₂, has been synthesized and characterized using single-crystal X-ray diffraction and spectroscopy (IR, UV–Vis, MS and EA). Complex [Co(NNS)₂] crystallizes in the orthorhombic, space group Pna2(1). The coordination geometry around Co(II) in the complex is distorted octahedral and the two ligands in the mer-configuration (S and tertiary N atom cis to each other and the iminic N atoms trans). Furthermore, the neutral molecule unit Co^II(NNS)₂ is connected by hydrogen bonds C–H ··· S and forms a three dimensional ordered network structure.     

Complexes with diimine ligands. Syntheses and magnetic behaviour of dinuclear complexes of copper(II), nickel(II) and cobalt(II) with 2,5-bis(2-pyridyl)pyrazine

Summary The synthesis, characterization and voltammetric and magnetic behaviour of a series of dinuclear complexes -(2,5-DPP)[M(hfacac)₂]₂, in which hfacac is hexafluoro-acetylacetonate, 2,5-DPP is 2,5-bis(2-pyridyl)pyrazine and M = copper(II), nickel(II) and cobalt(II), are described. As with the dinuclear complexes derived from 2,3-bis(2-pyridyl)-pyrazine (2,3-DPP) and analogous ligands, magnetic measurements show that these systems are not coupled. On the basis of magnetic data, we propose that, in contrast to related ligands such as 2,2-bipyridyl, the coordinated 2,5-DPP cannot be planar.     

A novel three-dimensional cobalt(II)-radical complex Co(NITmPy)2[N(CN)2]2: Structure and magnetic properties

A novel three-dimensional cobalt(II)-radical complex {Co(NITmPy)₂[N(CN)₂]₂}_n (NITmPy = 2-(3′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) is prepared and characterized by X-ray crystallography. The complex crystallizes in the monoclinic system, space group P2₁/c, with unit cell parameters a = 12.5775(5) Å, b = 10.9340(5) Å, c = 11.6134(5) Å, β = 108.1320(10)°; V = 1517.79(11) ų, ρ_calcd = 1.443 g/cm³, and Z = 2 for R ₁ = 0.0463. In the complex, each cobalt ion is six-coordinate with four nitrogen atoms from four N(CN) ₂ ^t- ligands and two nitrogen atoms of pyridyl groups, and the [Co(NITmPy)₂]²⁺ units are linked by N(CN) ₂ ^t- μ-bridging ligands to form a three-dimensional structure. The variable-temperature magnetic susceptibility data show that the complex exhibits weak antiferromagnetic interactions.     

Study of the complex formation between 4, 6-diamine-1, 2-dihydro-2-thiopyrimidine and cobalt(II), cobalt(III), nickel(II) and copper(II) ions

Summary Reactions of 4, 6-diamine-1, 2-dihydro-2-thiopyrimidine (HDATP) with cobalt(II), nickel(II) and copper(II) ions in 12 metal:ligand ratio in aqueous media at 25°C and 0.1 M ionic strength (KNO₃), lead to the formation of both [M(DATP)]⁺ and [M(DATP)₂] species, whose stability constants were obtained.On the other hand, in aqueous or ethanolic media, solid complexes with 11, 12, or 13 stoichiometries were isolated. These have been characterized by analytical, i.r. and electronic spectral and magnetic measurement studies, and tentative structures are proposed.     

Synthesis and molecular structure of cobalt(II) complex with 1-(1-silatranylmethyl)-1,2,4-triazole

Reaction of cobalt chloride with 1-(1-silatranylmethyl)-1,2,4-triazole in benzene afforded complex CoCl₂·2L (L = 1-(1-silatranylmethyl)-1,2,4-triazole). It was isolated as the solvate [CoCl₂·2L]·CH₂Cl₂ (1) by recrystallization from dichloromethane and structurally characterized by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group P2₁/m with a = 6.798(2) E, b = 20.326(5) E, c = 11.005(3) E, and Z = 4. The cobalt atom is in slightly distorted square-planar environment, coordinated to two nitrogen atoms from two ligands and two chloride ions.     

Synthesis and crystal structure of cobalt(II) complex with 2-diphenylacetyl-1,3-indandione

The structure of the synthesized compound of cobalt(II) with 2-diphenylacetyl-1,3-indandione (HL) and two dimethyl sulfoxide molecules was studied by X-ray single-crystal diffraction. One of the dimethyl sulfoxide molecules is disordered over two positions. Crystals of the compound are triclinic: Z = 2, space group P1, a = 11.510(6) Å, b = 11.686(6) Å, c = 16.667(8) Å, α = 93.14(1)°, β = 108.48(1)°, γ = 96.34(1)°. The deprotonated ligand molecules in the inner coordination sphere are located in the equatorial plane of the cobalt coordination polyhedron in the cis configuration. The two DMSO molecules are monodentate coordinated to the central atom through oxygen donor atoms and occupy axial positions.     

Room temperature phosphorescence from a platinum(II) diimine bis(pyrenylacetylide) complex

Room temperature phosphorescence has been observed in a synthetically facile Pt(II) complex, Pt(dbbpy)(CtriplebondC-pyrene)(2) (dbbpy = 4,4'-di(tert-butyl)-2,2'-bipyridine; CtriplebondC-pyrene = 1-ethynylpyrene), in fluid solution. The static and time-resolved absorption and luminescence data are consistent with phosphorescence emerging from the appended CtriplebondC-pyrenyl units following excitation into the low energy dpi Pt --> pi* dbbpy metal-to-ligand charge transfer absorption bands.