Synthesis, crystal structures, and magnetic properties of a new nickel(II) complex with nitronyl nitroxide

A new nickel(II) complex [Ni(NIT-1′-MeBzIm)₂(H₂O)₂] · ClO₄ · H₂O (NIT-1′-MeBzIm = 2-{2′-[(l′-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) has been prepared and structurally characterized by single-crystal X-ray diffraction. Complex I crystallizes in monoclinic, space group C2/c, Z = 4. Crystal data: C₃₀H₄₆N₈O₁₆ClNi, Mr = 869.06, a = 13.958(3), b = 15.904(4), c = 18.514(5) Å, β = 101.047(3)°. The X-ray analysis reveals that Ni²⁺ ion resides in a distorted octahedron center, the complex was linked by intermolecular hydrogen bonds, resulting in a 2D network configuration. Magnetic investigation indicates the existence of interamolecular interactions is antiferromagnetic with J = ?40.76 cm^?1.     

Synthesis and crystal structures of cobalt(II) and nickel(II) complexes containing nitronyl nitroxide radical and dicyanamide

Two new complexes [Co(NIT-1′-MeBzIm)₂(Dca)₂] (I) and [Ni(NIT-1′-MeBzIm)₂(Dca)(H₂O) · NO₃ · H₂O (II) (NIT-1′-MeBzIm = 2-{2′-[(l′-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; Dca = N(CN)₂) were prepared and structurally characterized by single-crystal X-ray diffraction. Relevant crystallographic parameters are as follows: monoclinic, P2_1/c space group, Z = 4; crystal data: C₃₄H₃₈N₁₄O₄Co, M = 765.71, a = 14.343(4), b = 14.322(4), c = 18.626(5) Å, β = 105.956(3)° for I. Orthorhombic Pna2₁ space group, Z = 4; crystal data: C₃₂H₄₂N₁₂O₉Ni, M = 797.49, a = 24.426(4), b = 11.0326(18), c = 13.980(2)Å for II. The X-ray analysis reveals that Co²⁺ ion and Ni²⁺ ion resides in a approximate sdistorted octahedron center. In I, the complex was linked by intermolecular hydrogen bonds, resulting in a 1D chain configuration. In II, the complex was linked by intermolecular hydrogen bonds, resulting in a 2D network configuration.     

Synthesis,crystal structure and magnetic properties of a nickel(II) complex with pyridine-substituted nitronyl nitroxide radicals

The complex [Ni(NIT2Py)(PDA)(H₂O)]·(MeOH)(H₂O) [NIT2Py = 2-(2-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; PDA = 2,6-pyridine dicarboxylic acid] has been prepared and structurally characterized. The Ni^II ion is in a distorted octahedral environment: one nitrogen atom and one oxygen atom from the NIT2Py, one nitrogen atom from the PDA and one oxygen atom from the H₂O in the basal plane; two oxygen atoms from the PDA in the axial position. The units of [Ni(NIT2Py)(PDA)(H₂O)] were connected as a one dimension chain by intermolecular hydrogen bonds. The complex exhibits intramolecular antiferromagnetic interactions between the Ni^II ion and the NIT2Py.     

Synthesis,crystal structure and magnetic properties of a nickel(II) complex containing a 2-pyridyl-substituted nitronyl nitroxide

A new complex of formula [Ni(NIT2Py)₂Cl(H₂O)]Cl·2CH₃OH, where NIT2Py is 2-(2′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, was synthesized and characterized structurally and magnetically. The structure consists of a [Ni(NIT2Py)₂Cl(H₂O)]⁺ ion, a chloride anion and two methanol molecules. The nickel(II) ion lies in a distorted octahedral environment; two nitrogen atoms and two oxygen atoms from NIT2Py ligands from the basal plane; one oxygen atom from a water molecule and one chloride anion occupy axial positions. Variable temperature magnetic susceptibility data show that there is strong antiferromagnetic coupling between the nickel(II) ion and nitronyl nitroxide radicals. The results suggest that the sign of the magnetic interaction depends on structural and ligand effects.     

Synthesis,crystal structures and magnetic properties of nitronyl nitroxide radical-coordinated copper(II) complexes

Transition Metal Chemistry - The coordination compound constructed for nitronyl nitroxide radical NIT-Ph-4-Br and CuII(hfac)2(H2O)2 building blocks...     

Synthesis and crystal structures of the Zn(II) and Co(II) complexes containing the reduced derivative nitronyl nitroxide

Two complexes of formulas [Zn(Hfac)₂(IM-IMH-Bph)] (I) and [Co(Hfac)₃](IM-Bph) (II), where IM-Bph = 2,2′-bis(1′-oxyl-4′,4′,5′,5′-tetramethylimidazoline-2′-yl)-bis(2-formylphenyl) ether; Hfac = hexafluoroacetylacetonate, have been synthesized and characterized by single-crystal X-ray diffraction. The X-ray analysis demonstrates that both I and II are mononuclear complexes. In I, each zinc ion is five-coordinated with four oxygen atoms from two Hfac ligands and one oxygen atom from nitroxide. Complex II contains one Co(III) atom with six oxygen atoms from three Hfac ligands and uncoordinated IM-Bph diradical, in which the Co²⁺ ion and NIT-Bph biradical can undergo the redox reaction.     

Synthesis, crystal structure, and magnetic properties of a new manganese(II) complex with nitronyl nitroxide

A new manganese(II) complex [MnCl₂(NIT-1′-MeBzIm)₂] · 3H₂O (NIT-1′-MeBzIm = 2-{2′-[(l′-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) has been prepared and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in monoclinic, space group C2/c, Z = 4. Crystal data: C₃₀H₃₈Cl₂MnN₈O₈, M = 764.52, a = 17.261(3) Å, b = 21.317(4) Å, c = 11.744(2) Å, β = 108.464(2)°. The X-ray analysis reveals that Mn(II) atom is six-coordinated with a distorted octahedral geometry. The complex was linked by intermolecular hydrogen bonds, leading to a 2D network configuration. Magnetic investigation indicates the existence of interamolecular interactions is ferromagnetic with J = 1.11 cm^?1.     

1D chlorine bridged mercury(II) complex containing nitronyl nitroxide radicals: Synthesis, crystal structures, and magnetic properties

A novel 1D chlorine bridged mercury(II) complex containing nitronyl nitroxide radicals, [Hg₂(NIT-1′-MeBzIm)Cl₄] _n (NIT-1′-MeBzIm = 2-{2′-[(1′-methyl)benzimidazolyl]}-4,4,5,5-tetrameth-ylimidazoline-1-oxyl-3-oxide), has been prepared and characterized by magnetic and single-crystal X-ray diffraction studies. The complex crystallizes in triclinic, space group P $\bar 1$ , Z = 2. Crystal data: C₁₅H₁₉C₁₄Hg₂N₄O₂, M = 830.32, a = 7.4454(16), b = 9.463(2), c = 16.180(3) Å, α = 94.245(2)°, β = 100.747(2)°, γ = 102.523(2)°, V = 1085.5(4) ų, ρ _c = 2.540 g/cm³, μ(MoK_α) = 14.636 mm^?1, F(000) = 762, R = 0.0312 and wR = 0.0779 for 3990 observed reflections with I > 2σ(I). The X-ray analysis reveals that the Hg²⁺ ions shows two coordination geometries of five-coordinated with a distorted square pyramidal coordination geometry and quadrilateral geometry. The units of [Hg₂(NIT-1′-MeBzIm)C_l4] _n were connected as 1D chain structure by the chlorine bridges. Magnetic investigation indicates the existence of weak intramolecular interactions is antiferromagnetic with J = ?1.23 cm^?1, where the spin Hamitonian is defined as H = $ - 2\sum\nolimits_{i,j} {J_{i,j} S_i S} $ within the complex.     

Synthesis,crystal structure and ferromagnetic properties of a novel acetate bridged dicadmium(II) complex with nitronyl nitroxide

The novel dinuclear cadmium(II) complex [Cd₂(NIT-1′-MeBzIm)₂(CH₃COO)₄] (I), where NIT-1′-MeBzIm = 2-{2′-[(1′-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, has been prepared and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in monoclinic crystal system, space group C2/c, Z = 4. Crystal data: C₃₈H₅₀Cd₂N₈O₁₂, M _r = 1035.66, a = 18.6492(16), b = 11.9605(10), c = 19.9208(17) Å, β = 92.1650(10)°. The X-ray analysis reveals that two Cd(II) atoms were bridged by two acetate groups to form a centrosymmetric Cd(II)-Cd(II) dinuclear entity, Cadmium atom is six-coordinated with a distorted octahedral geometry. The complex is linked by intermolecular hydrogen bonds leading to a 2D network configuration. Magnetic investigation indicates the existence of weak intramolecular interactions; i.e., the complex I is ferromagnetic with J = 1.97 cm^?1.     

Synthesis, characterization and crystal structures of manganese (Ⅱ) complexes containing nitronyl nitroxide and its reduced derivative

Two novel adducts of formula Mn(hfac)2( NITPhCl )2 (1) and [Mn(hfac)2(IMHPhCl)]2(NIT-PhCl)·0.5H2O (2), where hfac = hexafluoroacetylacetonate, NITPhCl = 2-(3-chlorophenyl)-4,4,5,5-tetram-ethylimidazolyl-1-oxyl-3-oxide, IMHPhCl = 2-(3-chlorophenyl)-4, 4, 5, 5-tetramethylimidazolyl-3-oxide, have been prepared by the reaction of Mn(hfac)2·2H2O with NITPhCl. Compound 1 is triclinic, space group P-1with a = 1.3003(3) nm, 6 = 1.3138(3) nm,c = 1.4931 (3) nm, α = 83.74(3)°, β = 77.77(3)°, γ = 60.59(3)°, V=2.171(1)nm3, Z = 2. Compound 2 is triclinic, space group P-1 with a = 1.2994(3) nm, b = 1.4841(3) nm, c = 2.1031 (4) nm, a = 92.30(3)° ,p = 98.68(3)°, γ = 97.89(3)°, V= 3.964(2)nm3, Z = 2. Each manganese atom is hexacoordinated in both compounds and compound 2 is organized inchains by hydrogen bonds between neighboring pairs of NITPhCl and IMHPhCl.     

Syntheses,crystal structures and magnetic properties of a new thienyl-substituted nitronyl nitroxide and its copper(II) complex

A new building block for molecule-based magnetic materials???thiophene-substituted nitronyl nitroxide, NIT2-thp, [1, NIT2-thp?=?4,4,5,5-tetramethyl-2-(thiophenal-2-yl)imidazoline-1-oxyl-3-oxide] and its copper(II) complex [Cu(hfac)₂]₃(NIT2-thp)₂ (2) (hfac?=?hexafluoroacetylacetonate) have been synthesized and characterized structurally and magnetically. For 1, dimers were formed and arranged through intermolecular interactions, the shortest contact between nitroxide groups is 4.115?Å among adjacent dimers. In 2 two types of copper interaction with 1 give three colinear Cu(II) ions linked by two μ???1,4 bridging nitroxide ligands. The central metal ion is in a distorted octahedron, axially coordinated by two nitroxide oxygen atoms, while the two external metal ions are in distorted square-pyramidal environments with the nitroxide oxygen atom coordinated in the basal plane. Magnetic susceptibility data for 1 and 2 have been measured in the range 3–300?K. There are antiferromagnetic interactions (J?=??3.89?cm^?1) between the dimers of 1 and also ferromagnetic interactions in 2. The magnetic properties of 1 and 2 are discussed in connection with their crystal structures.     

A new zinc(II) complex containing nitronyl nitroxide radicals: Synthesis, crystal structure, and magnetic properties

A new one-dimensional dicyanamide bridged zinc(II) complex containing nitronyl nitroxide radicals [Zn(Hfac)₂(NIT-1′-MeBzIm)] (NIT-1′-MeBzIm = 2-{2′-[(l′-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, Hfac = hexafluoroacetylacetonate) has been prepared and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in monoclinic, space group P2₁/c, Z = 4. Crystal data: C₂₅H₂₁F₁₂N₄O₆Zn, Mr = 766.83, a = 12.1812(13) Å, b = 16.8770(18) Å, c = 15.5230(16) Å, β = 98.009(2)°, V = 3160.1(6) ų, ρ _c = 1.612 g/cm³, μ(MoK _α) = 0.893 mm^?1, F(000) = 1540, R = 0.0925 and wR = 0.2652 for 5875 observed reflections with I > 2σ(I). The X-ray analysis reveals that the zinc(II) ion is six-coordinated with a distorted octahedral geometry. These units develop as 1D species by intermolecular hydrogen bonds. Magnetic investigation indicates the existence of weak intermolecular interactions is antiferromagnetic with J = ?1.35 cm^?1, where the spin Hamitonian is defined as H = ?2Σ _i,j J _i,j S _i S within the complex.     

Synthesis,crystal structures,and magnetic properties of cobalt(II)-hexafluoro-acetylacetonate complexes with two new triazole-substituted nitronyl and imino nitroxide

Two new chelating radical ligands, NITphtrz (4,4,5,5-tetramethyl-2-(2-phenyl-1,2,3-triazole-4-yl)imidazoline-1-oxyl-3-oxide) and IMphtrz (4,4,5,5-tetramethyl-2-(2-phenyl-1,2,3-triazole-4-yl)imidazoline-1-oxyl), and their cobalt(II) complexes [Co(Hfac)₂(NITphtrz)] (I) and [Co(Hfac)₂(IMphtrz)] (II) (Hfac = hexafluoroacetylacetonate) have been prepared and characterized by IR, magnetic, and single-crystal X-ray analysis. The magnetic behaviors of the lignad NITphtrz and complex I have been discussed.     

Synthesis and crystal structure of a new copper(II) binuclear complex bridged by the reduced derivative of a nitronyl nitroxide biradical

A new copper(II) binuclear complex, [Cu(hfac)₂]₂(IMH)₂Ph(OMe)₂ ((IMH)₂Ph(OMe)₂?=?2,5-dimethoxyl-1,4-bis(4′,4′,5′,5′-tetramethylimidazoline-3′-oxide)benzene, hfac?=?hexafluoroacetonate), bridged by a reduced derivative of a nitronyl nitroxide biradical has been synthesized and characterized by X-ray crystallography. The complex crystallizes in the monoclinic space group P2₁/n, with a?=?10.002(14), b?=?19.950(3), c?= 14.504(2) Å, β?=?108.842(3)° and Z?=?2. The structure refined to a final R value of 0.0644. The complex contains two copper(II) ions bridged by a reduced derivative of a nitronyl nitroxide biradical with a Cu?···?Cu separation of 8.430(2) Å.     

A novel one-dimensional dicyanamide bridged lead(II) complex containing nitronyl nitroxide radicals: Syntheses,crystal structures,and magnetic properties

A novel one-dimensional dicyanamide bridged lead(II) complex containing nitronyl nitroxide radicals, [Pb(NIT-1′-MeBzIm)(Dca)₂] _n (Dca = dicyanamide anion, NIT-1′-MeBzIm = 2-{2′-[(l′-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), has been prepared and characterized by magnetic and single-crystal X-ray diffraction studies. In the complex, Pb²⁺ ion shows seven-coordinate geometry. A chain structure with single, symmetrical, end-to-end Dca bridges is found in the compound. These units develop as 1D species, where dicyanamide ligands bridge Pb²⁺ ions. Otherwise, molecules are linked by π-π-piling interactions to form 2D network structure. Magnetic investigation indicates the existence of intramolecular interactions, wich are ferromagnetic with J = 23.6 cm⁻¹, where the spin Hamitonian is defined as H = −2Σ _i,j J _i,j S _i S within the complex.     

Synthesis,structure, and properties of a 1-D copper(II) complex with nitronyl nitroxide radicals

A 1-D chain complex [Cu(NIT4Py)(IDA)]_∞ (NIT4Py = 2-(4′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and IDA = iminodiacetate) has been prepared and characterized by single-crystal X-ray diffraction, IR, TGA, and magnetic analysis. Each Cu(II) is five-coordinate with distorted square pyramidal geometry. Each IDA bridges two Cu(II) ions via one carboxylate which occupies the axial site of Cu(II), leading to a chain structure composed of Cu(II)-radical cations and IDA anions. In the complex, there exist three magnetic exchange pathways, (i) interaction between units of (Cu(II)-NIT4Py) through IDA, (ii) Cu(II)-NIT4Py interaction, and (iii) NIT4Py-NIT4Py interaction through space. Compared with the first two magnetic interactions, the last magnetic exchange interaction should be too weak to be counted because of the large distance of the neighboring NIT4Py molecules (4.993 Å). Analysis of the magnetic properties was performed using the Bleany–Bowers (dimer) model, showing that the complex exhibited both weak antiferromagnetic interaction between the Cu(II) and NIT4Py, and between the units of (Cu(II)-NIT4Py) through IDA with exchange coupling parameters J = ?7.28 cm^?1 and zJ′ = ?0.40 cm^?1.     

Synthesis and crystal structure of dinuclear nickel (Ⅱ) complex

The crystal structure of Ni(Ⅱ) complex with 3-hydroxyl-1, 5-diazacycloheptane-N, N'-diacetate was determined by X-ray diffraction method. Crystal data for Ni2 (C9H14N2O5)2·2H2O: monoclinic, space group P21/n, a = 1.1717(5), b = 0.9794(3), c = 1.2971(2) nm, β= 96.62(3), V= 1.4786(7) nm3, Dc = 1.377 g/cm3, Z = 2,μ=13.321 cm-1 (Mo-Kα), F(000)=640. The final R and Rw are 0.075 and 0.089 respectively. The Ni(Ⅱ) ion forms 2:2 complex with ligand. Two ligands are bridged by two Ni(Ⅱ) atoms which are bridged by two O atoms. Every Ni(Ⅱ) is coordinated by two N atoms and four 0 atoms. The coordination polyhedron of the Ni(Ⅱ) ion is a distorted octahedron.     

Synthesis and magnetic properties of nickel(II) complexes with the nitronyl nitroxides

Four novel complexes of nickel(II), Ni(tfac)2(NITPa)2 (1), Ni(tfac)2(NITPhNO2)2 (2), Ni(pfpr)2(NITPa)2 (3) and Ni(pfpr)2(NITPhNO2)2 (4), [tfac=trifluoro- acetato, NITPa=2-(3,4-methylenedioxyphenyl)-4,4,5, 5-tetramethylimidazoline-1-oxy-3-oxid, NITPhNO2= 2-(3-nitrophenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxid, pfpr=pentafluoropropionato], have been prepared and characterized by elemental analysis, i.r., and electronic spectra, and molar conductances. The temperature dependence of the magnetic susceptibility for complexes (1) and (3) was measured (4–300K). The observed data were successfully simulated giving the exchange integral J=–1.48cm–1 for (1) and J=–1.25cm–1 for (3). These results indicate a weak antiferromagnetic spin exchange interaction between nickel(II) ion and the radicals.     

Synthesis,structures and magnetic properties of copper (II) and cobalt (II) complexes containing pyridyl-substituted nitronyl nitroxide and 3,5-dinitrobenzoate

Four new metal-radical complexes - [Cu(NIT3Py)₂(DTB)₂] 1, [Co(NIT3Py)₂(DTB)₂(CH₃OH)₂] 2, [Cu(NIT4Py)₂(DTB)₂(H₂O)₂] 3, [Co(NIT4Py)₂(DTB)₂(H₂O)₂] 4, (NIT3Py = 2-(3^′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide], NIT4Py = 2-(4^′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide], DTB = 3,5-dinitrobenzoic anion) have been synthesized by using transition metal ions, nitronyl nitroxide radicals as spin carriers, and incorporating 3,5-dinitrobenzoic acid (DTB) as a coligand.