Synthesis,crystal structure and magnetic properties of a new cyanide-bridged two-dimensional CrIII2CoII3 ferromagnet

A new cyanide-bridged Cr^IIICo^II heterometallic complex {[Co(L-N₅)]₃[Cr(CN)₆]₂}_n·nCH₃CN·5nH₂O (1) has been synthesized by the reaction of [Co^II(L-N₅)₂(H₂O)₂]·(ClO₄)₂ with the hexacyanidechromate(III) building block K₃[Cr^III(CN)₆]. X-ray single crystal diffraction analysis shows that complex 1 has a two-dimensional (2D) layer-like structure. Magnetic investigations show that the magnetic coupling between Cr(III) and Co(II) ions through cyanide bridge is ferromagnetic for the complex. The complex displays typical soft ferromagnet behaviors with a three-dimensional ferromagnetic ordering of T_c = 15.0 K, a small coercive field of 10 Oe and a remnant magnetization of about 7.8 Nβ.     

Alkoxo- and carboxylato-bridged hexanuclear copper(II) complex: Synthesis,structure and magnetic properties

Reaction of copper(II) nitrate trihydrate with N,N-dimethylethanolamine (dmea) and pivalic acid in methanol led to the hexanuclear copper(II) complex Cu₆(η¹:μ₂-C₄H₁₀NO)₄(η¹:η¹:μ₂-C₅H₉O₂)₄(η¹:μ₁-C₅H₉O₂)₂(μ₃-OH)₂ (1). The crystal structure of 1 indicates that hexametallic centers are bridged by the μ₃-alkoxo, dmea oxygens, and the μ₂-dicarboxylato oxygen atoms of pivalate ions. Furthermore, in the asymmetric unit, three types of copper ions have been found labeled as Cu₁, Cu₂ and Cu₃. The Cu₂ takes a distorted octahedral shape, whereas Cu₁ and Cu₃ adopt square pyramidal geometries. The complex 1 shows strong antiferromagnetic interactions through the oxo groups within the dimeric units (J = − 82.6 to − 25.8 cm^− 1) and weak antiferromagnetic couplings between the dimers (J = − 10.9 and 0.8 cm^− 1).     

Synthesis,structure and properties of a new NH-1,2,3-triazole-based octanuclear copper(II) complex

An octanuclear copper complex, [Cu₈(L)₁₀(OH)₄Cl₂·(DMF)₂]·2DMF ( HL= 4-(2-bromophenyl)-2H-1,2,3-triazole) has been synthesized. Single crystal diffraction reveals that it crystallizes in the triclinic space group P − 1. The complex shows fluorescent quenching compared with the free ligand. The {Cu₈} displays overall strong antiferromagnetic (AF) coupling via hydroxyl groups, κ₂-N,N-trizaoles and κ₃-N,N,N-trizaoles, and the complex exhibits AF ordering under low temperature with T_N = 8.5 K.     

Synthesis, crystal structure and luminescent properties of a thiocyanato bridged two-dimensional heteronuclear polymeric complex of cadmium(II) and copper(II)

A novel heteronuclear polymeric complex Cd(SCN)₃Cu(en)₂NO₃ (1) (en = ethylenediamine) has been synthesized and structurally characterized. The Cd(II) atom is surrounded by three S atoms and three N atoms from four 1,3-μ-SCN⁻ and two 1,1,3-μ-SCN⁻ to attain a distorted octahedral coordination geometry. Six Cd(II) centers are linked by twelve thiocyanato bridges to form hexagonal metallocyclic unit [Cd₆(SCN)₁₂] and extend a 2D network. Moreover, a 1,1,3-μ-SCN⁻ links two cadmium and one copper metal atoms. The luminescent properties of 1 in the solid state were investigated.     

Synthesis,crystal structure,and magnetic property of a stepped tetranuclear copper(II) complex of 3,5-diisopropylpyrazole-1-methoxide

Reaction of copper(II) chloride dihydrate in methanol with deprotonated 3,5-diisopropylpyrazole-1-methanol (dippmOH) led to the tetranuclear copper(II) complex [(dippmO)CuCl]₄ (1). The crystal structure of 1 indicates that two copper(II) ions connect via the oxygen atoms of dippmO⁻ ligands each other in which two dimeric units are formed. Furthermore, one of the coordinated oxygen atoms in a dimer is bonded to an adjacent copper(II) ion positioned other dimer, which gives rise to a stepped tetranuclear structure. 1 shows strong antiferromagnetic interactions through the oxo groups within the dimeric units (J₁ = − 239 cm^− 1) and weak antiferromagnetic couplings between the dimers (J₂ = − 15 cm^− 1).     

Synthesis,crystal structure and photoluminescent properties of a 3D Zn(II) coordination polymer

A new 3D coordination polymer [NH₂(CH₃)₂]₂[Zn₇L₄(DMF)₂(H₂O)₃]·19H₂O (1) (L = 2,3′,5,5′-biphenyl tetracarboxylic acid) has been solvothermally synthesized and structurally characterized by IR, elemental analysis and single-crystal X-ray diffraction. Single-crystal X-ray diffraction studies indicate that 1 exhibits 3D framework with a one-dimensional (1D) channel. The luminescence properties have been studied, and the results showed that 1 displays strong fluorescent emissions both in the solid state and in methanol suspension at room temperature. More interesting, the addition of Fe^3 + causes the fluorescence intensity of 1 to be weakened, which implies that it may be used as luminescent probes of Fe^3 +.     

Synthesis,crystal structure,luminescence and thermal behavior of a new energetic zinc(II) compound

An energetic material [Zn₂(btzphda)₂(H₂O)₄(dpp)₂]·2DMF·4H₂O with high decomposition enthalpy of − 748.35 J/g was prepared by the reaction of H₂btzphda, dpp and Zn(NO₃)₂·6H₂O under solvothermal conditions, where btzphda = 1,4-bis(tetrazol-5-yl)benzene-N2,N2′-diacetato, dpp = 1.3-di(4-pyridyl)propane and DMF = N,N′-dimethylformamide. The luminescence properties of H₂btzphda and [Zn₂(btzphda)₂(H₂O)₄(dpp)₂]·2DMF·4H₂O were investigated at room temperature in the solid state (Hitachi F4600 spectrofluorometer). Furthermore, the thermal decomposition behavior of the compound is characterized by differential scanning calorimetry (DSC) and thermogravimetric-differential thermogravimetric (TG-DTG) analyses. The entropy of activation (ΔH), enthalpy of activation (ΔS) and the free energy of activation (ΔG) for the decomposition temperature were ΔH = 250.64 kJ/mol, ΔS = 222.75 J·mol^− 1·K^− 1 and ΔG = 134.10 kJ/mol.     

New μ-oxo-bridged tetranuclear Cu(II) complex with Schiff-base ligand: Synthesis,crystal structure and magnetic properties

A new μ-oxo-bridged Cu(II) complex with cubane-like tetranuclear copper(II) complex, [Cu₄(L¹)₄] · 4H₂O (1) (H₂L¹ = 2-(3-methoxy-salicylidene-amino)-benzyl-alcohol), has been prepared, and structurally characterized by X-ray crystallography. Complex 1 crystallized in the monoclinic space group P₂₁/n and has a tetranuclear core of Cu₄O₄. The temperature dependence of magnetic susceptibility measurements shown that complex 1 exhibits a strong antiferromagnetic interaction with J = −103.4 cm⁻¹.     

Synthesis,crystal structure and nonlinear optical property of cadmium(II) and copper(II) complexes with novel chiral ligand

Two novel metal-organic frameworks (MOFs) [Cd(3-MPCA)₂ · H₂O] · 5.5H₂O (1) and [Cu(3-MPCA)₂ · H₂O] · 4H₂O (2) [3-MPCA⁻ = (1R, 3S)-1,2,2-trimethyl-3-(pyridin-3-ylmethylcarbamoyl)cyclopentanecarboxylate] were hydrothermally synthesized and characterized by X-ray crystallography. Complexes 1 and 2 are homochiral and have similar one-dimensional (1D) chain structure, which are further linked by strong hydrogen bonds to give 3D architectures. There are oxygen hexmers and heptamers from water molecules and carbonyl group in 1 with O⋯O distances and O–O–O angles comparable to the corresponding values in ice. Nonlinear optical measurements on powdered sample of 1 and 2 revealed that they display second-harmonic-generation (SHG) response of 0.8 and 0.3 times of that for urea, respectively.     

Synthesis,crystal structure and magnetic properties of a dinuclear dysprosium single-molecule magnet

To seek novel dysprosium based single-molecule magnets, a dinuclear dysprosium complex, namely [Dy₂(L)₂(DBM)₂(DMF)₂]·2DMF (1) was successfully obtained by employing tridentate Schiff base ligand (where H₂L = 2-hydroxy-N′’-(2-hydroxy-3-methoxybenzylidene) benzohydrazide), HDBM = dibenzoylmethane, DMF = dimethylformamide). Single-crystal X-ray structural analysis reveals that the key feature of 1 is neutral dinuclear complex, in which two Dy(III) ions with eight-coordinated environment are bridged by two phenoxido oxygen atoms from two Schiff base ligands. Interestingly, complex 1 could be regarded as the structurally related derivatives to our previous reported complex of [Dy₂(L)₂(DBM)₂(DMF)₂] (1a) but adding two guest DMF solvents. More importantly, the energy barrier to magnetic relaxation of 1 is slightly higher, with a value of 33 K, when compared to the corresponding complex 1a of 24 K, which provides a good example towards regulating magnetization dynamics in dinuclear dysprosium (III) single-molecule magnets by guest solvent molecules.     

One-pot template synthesis and crystal structure of two new polyaza copper(II) complexes

A new 14-membered hexazamacrocyclic copper(II) complex [Cu(H₂L¹)](ClO₄)₄(L¹=1,8-bis(2-aminoethyl)-1,3,6,8,10,13-hexaazacyclotetradecane) has been prepared by the one-pot reaction of ethylenediamine and formaldehyde in the presence of the Cu(II) ion. The crystal structure of [Cu(H₂L¹)](ClO₄)₄ was determined by X-ray diffraction. It crystallizes in the triclinic space group P−1 with a=12.118(2) Å, b=12.438(2) Å, c=12.466(2) Å, α=102.26(1)°, β=112.82(1)°, γ=111.51(1)°, and Z=2. The coordination geometry around the copper(II) ions is axially elongated octahedral with four nitrogen atoms of the macrocycle [Cu–N 2.012(7) Å for Cu(1) and 2.013(6) Å for Cu(2), average value] and two oxygen atoms of two ClO₄⁻ anions [Cu–O=2.550 Å for Cu(1) and 2.601(6) Å for Cu(2)]. [CuL²](ClO₄)₂(L²=3,7-bis(2-aminoethyl)-1,3,5,7-tetraazabicyclo[3,3,2]decane) with a novel tetraazabicyclic ligand was obtained from the same reaction system as an additional product. Crystal structure of [CuL²](ClO₄)₂: monoclinic space group Cc, a=16.393(3) Å, b=8.8640(18) Å, c= 13.085(3) Å, β=105.01(3)°, and Z=4.     

Synthesis,crystal structure and photoluminescence of a new Cd(II) coordination polymer with unusual geometry

A new coordination polymer 1 [CdL₂(NO₃)₂]_n (L: 3, 6-di-(1, 2, 4-triazole-1-yl)-N-ethylcarbazole) has been synthesized by self-assembly reaction and characterized by elemental analysis and IR spectroscopy. The single-crystal X-ray diffraction shows that the [CdL₂(NO₃)₂]_n crystallizes in the monoclinic system and C2/m space group and the Cd(II) atom is four-coordinated. The coordination polyhedron can be described as a rectangle which is rather infrequent. The coordination bonds, hydrogen bonds and π–π interactions shaped the 3D network structure. A possible formation mechanism was discussed. The optical property was also studied.     

Synthesis,crystal structure,characterization and magnetic property of a new organophosphonate-based polyoxovanadate

A novel organophosphonate-based polyoxovanadate, Cs_1·5Na_3.5[H{V₃(H₂O)O₃}{O₃PC- (OH)(CH₃)PO₃}₃]·15H₂O (1) has been synthesized and further investigated by single-crystal X-ray diffraction analysis, IR spectrum, UV–vis spectroscopy, X-ray powder diffraction, thermogravimetric analysis and X-ray photoelectron spectroscopy. Single-crystal X-ray analysis reveals that compound 1 crystallizes in the triclinic space group P-1 with a = 9.506(3) Å, b = 15.150(5) Å, c = 17.915(6) Å, V = 2437.9(14) ų and Z = 2. Compound 1 exhibits a ring-shaped cluster with three branches of the 1-hydroxyethane 1, 1-diphosphonic acid [HEDP = H₂O₃P(OH)C(CH₃)PO₃H₂] ligands. Furthermore, the magnetic property of compound 1 has also been studied.     

Synthesis,structure, and properties of dinuclear copper (II) complex with a (H2O)12 cluster

A novel pyrazole complex, namely [Cu₂(4,4′-bpy)₂(2,2′-bpy)(L)₂]·6H₂O has been synthesized under mild condition (4,4′-bpy = 4,4′-bipyridine, 2,2′-bpy = 2,2′-bipyridine). We report the structural evidence in the solid state of discrete water hexamers chair-like conformation. These units were found to act as supramolecular glue in the aggregation of dinuclear copper (II) complex to give a three dimensional network through hydrogen-bonding. The preliminary investigation on the electrochemical property and fluorescence property of the complex are presented.     

Synthesis and crystal structure of three dimensional complex from copper(II) and 1,2,4,5-benzenetetracarboxylate

A copper(II) complex {[Cu(H₂btc) (H₂O)₃]₂(H₄btc)(C₅H₁₁N)₂ · 3H₂O}_n (1) has been synthesized and characterized structurally (H₄btc=1,2,4,5-benzenetetracarboxylic acid). Open channels were formed and can accommodate piperidine molecules. TGA data show that guest water and piperidine molecules are lost at 130 °C.     

Synthesis,crystal structure and desulfurization properties of zig-zag 1D coordination polymer of copper(II) containing 4-methoxybenzoic acid ligand

ABSTRACT

Combustion of fuels containing organosulfur compounds has resulted in the emission of sulfur oxides (SO_x) into the atmosphere, therefore, causing serious environmental and health hazards. Herein, slightly distorted octahedral zig-zag 1D coordination polymer of copper(II) [Cu(4-mba)₂(H₂O)₃] was synthesized by reacting copper sulfate pentahydrate with a carboxylate-containing ligand (H-4mba?=?4-methoxybenzoic acid) and employed for sulfur compound uptake. The ligand coordinates to the copper(II) atom via two pairs of deprotonated ligating atoms (carboxylate oxygens) and two water molecules. Structural characterization also reveals that interplay of O–H···O, N–H···O, C-H···O and C–H···π interactions between lattice and coordinated water and ligands significantly contribute to the crystal packing leading to the formation and strengthening of three-dimensional supramolecular assembly. The complex, [Cu(4-mba)₂(H₂O)₃], show potential for desulfurization of fuel with an observed adsorption capacity of 9.6?mg/g at 32°C for 6?h. DFT calculations further revealed a transfer of electron sulfur-containing compounds and the complex, [Cu(4-mba)₂(H₂O)₃], thus leading to a stronger pi–pi interaction.     

The chiral Zn(II)–Na(I) coordination polymer: Synthesis, crystal structure, thermal and optical properties

The chiral Zn(II)–Na(I) coordination polymer with formula [NaZn(acac)₂(AcO)(EtOH)] (1) has been synthesized, and characterized by ¹H NMR and FT-IR spectra, elemental, X-ray, and thermogravimetric analysis (TGA). X-ray crystallographic study revealed that 1 crystallizes in the non-centrosymmetric space groups P2₁2₁2₁ and exhibits a one-dimensional polymer chain. Linear optical properties were investigated by UV/Vis spectrophotometer techniques. Kurtz–Perry powder second-harmonic-generation (SHG) test confirms the non-linear optical (NLO) property of the grown crystal.     

Synthesis,crystal structure and magnetic characterization of a dinuclear Mn(II) complex with double end-on azide ligands

A new dinuclear manganese(II) complex [MnL(N₃)₂]₂ · 2CH₃OH 1 has been synthesized and characterized crystallographically and magnetically. L is a tridentate Schiff base ligand which is derived from the reaction of pyridine-2-carbaldehyde and 2-aminoethylbenzimidazole. In the complex 1, each Mn(II) ion is coordinated by one L, one terminal azide ligand and symmetrical double end-on bridging azide ligands. The intermolecular hydrogen bonds extend the structure into a two-dimensional layer. Magnetic determination of 1 indicates that ferromagnetic exchange interaction between the two manganese(II) ions exist in this complex through the double end-on azide bridges.