A dinuclear copper(II) complex and a zigzag chain iron(II) polymer based on the 4-antipyrine derived Schiff base ligands: The hydroxylation and redox occurred under the solvothermal conditions

Crystal structure of catena-poly[dibromido-{μ2-1,5-dimethyl-2-phenyl-4-((pyridin-4-ylmethylene)amino)-1,2-dihydro-3H-pyrazol-3-one-κ2 N:O}zinc(II)], C34H32Br4N8O2Zn2

C34H32Br4N8O2Zn2, triclinic, P1̄ (no. 2), a = 11.441(2) Å, b = 13.422(2) Å, c = 14.370(3) Å, α = 101.129(3)°, β = 99.587(2)°, γ = 114.972(3)°, V = 1885.0(6) Å3, Z = 2, R gt(F) = 0.0510, wR ref(F 2) = 0.1775, T = 298(2) K.

Polynuclear ampyrone based 3d coordination clusters

The use of a monoanionic Schiff base ligand in transition (Co, Ni and Cu) coordination chemistry yields mono-, tetra- and pentanuclear coordination clusters with different structural motifs.

X-ray characterization and magnetic properties of dioxygen-bridged Cu(II) and Mn(III) Schiff base complexes

The coordination chemistry of multinuclear metal compounds is important because of their relevance to the multi-metal active sites of various metalloproteins and metalloenzymes. Multinuclear Cu(II) and Mn(III) compounds are of interest due to their various properties in the fields of coordination chemistry, inorganic biochemistry, catalysis, and optical and magnetic materials. Oxygen-bridged binuclear Mn(III) complexes generally exhibit antiferromagnetic interactions and a few examples of ferromagnetic interactions have also been reported. Binuclear Cu(II) complexes are important due to the fact that they provide examples of the simplest case of magnetic interaction involving only two unpaired electrons. Two novel dioxygen-bridged copper(II) and manganese(III) Schiff base complexes, namely bis(μ-4-bromo-2-{[(3-oxidopropyl)imino]methyl}phenolato)dicopper(II), [Cu2(C10H10BrNO2)2], (1), and bis(diaqua{4,4'-dichloro-2,2'-[(1,1-dimethylethane-1,2-diyl)bis(nitrilomethanylylidene)]diphenolato}manganese(III)) bis{μ-4,4'-dichloro-2,2'-[(1,1-dimethylethane-1,2-diyl)bis(nitrilomethanylylidene)]diphenolato}bis[aquamanganese(III)] tetrakis(perchlorate) ethanol disolvate, [Mn(C18H16Cl2N2O2)(H2O)2]2[Mn2(C18H16Cl2N2O2)2(H2O)2](ClO4)4·2C2H5OH, (2), have been synthesized and single-crystal X-ray diffraction has been used to analyze their crystal structures. The structure analyses of (1) and (2) show that each Cu(II) atom is four-coordinated, with long weak Cu...O interactions of 2.8631 (13) Å linking the dinuclear halves of the centrosymmetric tetranucelar molecules, while each Mn(III) atom is six-coordinated. The shortest intra- and intermolecular nonbonding Mn...Mn separations are 3.3277 (16) and 5.1763 (19) Å for (2), while the Cu...Cu separations are 3.0237 (3) and 3.4846 (3) Å for (1). The magnetic susceptibilities of (1) and (2) in the solid state were measured in the temperature range 2-300 K and reveal the presence of antiferromagnetic spin-exchange interactions between the transition metal ions.

Cu(I), Co(II) and Fe(II) coordination polymers with pyrazine and benzoate as ligands. Spin crossover, spin canting and metamagnetism phenomena

The isolation and characterization of four coordination polymers obtained by direct reactions of metal ion salts of Cu(II), Co(II) and Fe(II) with pyrazine (pyz) and benzoic/benzoate (Bz) ligands under hydrothermal or hydrothermal microwave conditions are described. The use of copper(II) perchlorate as the starting salt allows us to obtain compounds in a selective way by changing the pH values giving rise to the formation of two 3D-coordination polymers: [Cu(pyz)2]ClO4·pyz (1) and [Cu2(pyz)4](ClO4)2·HBz·H2O (2). In both polymers, 4-connected Cu(I) uninodal coordination networks with significant structural differences between them, due to the templating effect of the solvation molecules and counterions, have been found. However, reactions carried out under similar conditions with MSO4 (M = Co and Fe) led to the isolation of two [M2(μ-Bz)2(μ-pyz)2(Bz)2]·(HBz) isostructural infinite 1D ladder chains (M = Co (3) and M = Fe (4)). These coordination polymers show a spin-canting antiferromagnetism and metamagnetism behaviour for Co(II) and HS ↔ HS/LS ↔ LS spin-crossover phenomena for Fe(II), respectively. The latter compound is the first example of a Fe(II)O4N2 coordination environment showing this phenomenon.