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 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.     

二二甲亚砜合硫氰酸镉（DSTC）晶体的合成、结构、表征与晶体生长

合成了金属有机配合物晶体二二甲亚砜合硫氰酸镉Cd(SCN) 2 (C2 H6 OS) 2 (简称DSTC)。用X射线四圆衍射方法确定了此化合物的晶体结构。用元素分析、红外光谱对其进行了化学表征。首次在DMSO/水的溶剂中 ,生长出尺寸为 3 5mm× 12mm× 11mm透明单晶。     

Copper(II) and cadmium(II) complexes derived from Strandberg-type polyoxometalate clusters: Synthesis,crystal structures,spectroscopy and biological activities

Three Strandberg-type polyoxometalate compounds [Cu(L)₂(H₂O)₂]₂H₂[P₂Mo₅O₂₃]·2CH₃OH (1), [Cu(L)₂(H₂O)]H₂[Cu(L)₂(P₂Mo₅O₂₃)]·4H₂O (2), [Cd(L)₂(H₂O)₂]₂H₂[P₂Mo₅O₂₃]·2CH₃OH (3), (L = pyridine-2-carboxamide) have been synthesized and structurally characterized by elemental analysis, spectroscopic methods (IR and UV–vis) as well as single crystal X-ray diffraction. Single-crystal X-ray structural analyses indicate that 1 and 3 are isostructural and crystallized in monoclinic, space group I2/a. Biological studies have indicated that compounds 1–3 exhibit broad and effective activities against the tested cells. A synergistic effect involving L, metal and P₂Mo₅ could probably explain the improved growth-inhibiting properties. Both coordination mode and the type of metal ion play significant roles in these compounds cytotoxicity.     

Synthesis, crystal structure and photophysical properties of a series of new neutral iridium(III) complexes with 2-phenylpyridine

A series of new neutral iridium(III) complexes containing strong-field ancillary ligands, [Ir(ppy)₂(PPh₃)L] (ppy = 2-phenylpyridine, PPh₃ = triphenylphosphine, L = NCS⁻, 1; , 2; NCO⁻, 3), have been synthesized and fully characterized by ¹H NMR, IR, ESI mass spectral and elemental analysis. The crystal structure of 1 has been determined by X-ray analysis. The photoluminescence (PL) spectra of 1–3 show emission maxima at 477, 489 and 485 nm, respectively, corresponding to blue light-emitting of 1 and blue-green light-emitting of 2 and 3. PL quantum yields (PLQYs) of 1–3 are 0.39, 0.13 and 0.43, respectively.     

Synthesis of cadmium(II) hydroxide, cadmium(II) carbonate and cadmium(II) oxide nanoparticles; investigation of intermediate products

Sonochemical and hydrothermal routes have been used in different conditions for preparation of CdCO₃ and Cd(OH)₂ nanoparticles at air and inert atmospheres, respectively. The CdO nanoparticles were obtained by heating of CdCO₃ and Cd(OH)₂ nanoparticles at 400 °C. Powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) microscopy have been used to characterize the nanoparticles. The XRD results of intermediate products showed that the origin of CdCO₃ is CO₂ from air atmosphere.     

Synthesis,crystal structure and electrocatalytic activity of discrete and polymeric copper(II) complexes with bitopic bis(pyrazol-1-yl)methane ligands

New coordination copper(II) compounds containing bitopic bis(pyrazol-1-yl)methane ligands, namely 1,1,2,2-tetrakis(pyrazol-1-yl)ethane, 1,4-bis[bis(pyrazol-1-yl)methyl]benzene and 1,4-bis[bis(3,5-dimethylpyrazol-1-yl)methyl]benzene were prepared. Reactions of ligands with Cu^2 + ions in 1:2 ratio gave discrete homodinuclear complexes, while 1:1 ligand-to-metal ratio lead to the formation of coordination polymers. Electrocatalytic activity of compounds in oxygen electroreduction reaction on the surface of modified carbon paste electrode was evaluated.     

Synthesis,crystal structures and urease inhibitory activity of copper(II) complexes with Schiff bases

Two thiocyanate-coordinated Schiff base copper(II) complexes, [CuL¹(NCS)] (1) and [Cu₂(L¹)₂(μ_1,3-NCS)₂]_n (2), where L¹ and L² are the deprotonated forms of 4-bromo-2-[(2-propylaminoethylimino)methyl]phenol (HL¹) and 2-ethoxy-6-[(2-propylaminoethylimino)methyl]phenol (HL²), respectively, have been prepared and structurally characterized. Single crystal X-ray diffraction indicates that 1 is a mononuclear copper(II) complex, while in 2, the adjacent two complex molecules are linked through two phenolate O atoms, forming a dimer. The dimers in 2 are further weakly linked through end-to-end thiocyanate bridges to form a two-dimensional sheet. The Cu atom in 1 is four-coordinate in a square planar geometry, and that in 2 is six-coordinate in an octahedral geometry. Complex 1 shows strong urease inhibitory activity, while complex 2 shows no activity.     

Synthesis and X-ray crystal structure of a heteroleptic tris-cyclometalated iridium(III) complex

A convenient synthesis of the tris-cyclometalated complex [Ir(ppy)₂(nppy)] (2, ppy = 2-phenylpyridyl, nppy = 2-(4-nitrophenyl)pyridyl) from [{Ir(μ-Cl)(ppy)₂}₂] (1), the ligand 2-(4-nitrophenyl)pyridine, and silver trifluoroacetate as halide abstractor in refluxing methoxyethanol is described. The crystal and molecular structure of 2 was determined by a single-crystal X-ray diffraction study.     

Potentiometric and polarographic studies of cadmium(II) complexes with tetraethylenepentamineheptaacetic acid

Stability constants for cadmium(II) complexes with tetraethylenepentamineheptaacetic acid (TPHA, H₇L) were determined by the pH titration method. In an aqueous solution (μ = 0.1), three complex species, CdH₂L, CdHL and CdL are confirmed. The structure of uninuclear complexes are discussed. The formation constants of the complexes stated above have been calculated as follows (at 25 ± 0.1°C): log K_CdL = 15.35, log K_CdHL = 13.33 and log K_CdH2L = 7.89. The polarographic behaviour of the cadmium(II) in the presence of TPHA was studied over the pH range 3–5. Mechanisms of the electrode processes were elucidated and electrochemical kinetic parameters were evaluated from dependence of the half-wave potentials on the hydrogen ion and TPHA concentration. In the presence of an excess of TPHA, the wave B is assigned to the irreversible reductions of the complex, CdH₂L^3? (pH range 3–4) or CdHL^4? (pH range 4–5). The electrode reaction can be written:

and

Where k_e (the rate constant) = 2.3 × 10^?2 cm s^?1 and k′_e = 1.59 × 10^?4 cm s^?1. The other polarographic methods were also used in the elucidation of the electrode process.     

Caffeine in copper(II) complexes: crystal and molecular structure of di(caffeine)tetrakis(naproxenato)dicopper(II)

The crystal and molecular structure of di(caffeine)tetrakis(naproxenato)- dicopper(II) was determined by direct method and Fourier techniques. The structure was refined by full-matrix least-squares methods to a weighted R factor of 0.0705. The compound is binuclear with square pyramidal geometry at each copper(II) centre. The two copper(II) atoms are bridged by four carboxylate groups, while the apical ligands are caffeine molecules. The Cu–Cu distance is 2.649(2) Å. The Cu atoms are displaced by 0.217 Å from the plane containing four oxygen atoms bonded to Cu towards the apical caffeine molecules. The structural data are compared with those found in similar [Cu₂(RCOO)₄(caf)₂] (caf = caffeine) complexes.     

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.     

Transition metal complexes with Girard reagent-based ligands, Part I: Synthesis and crystal structure of the first cobalt(III) complexes with Schiff base derivative of Girard reagent

A new ligand, pyridoxilidene Girard-T hydrazone, [H₃L]Cl₂ · 2H₂O, and its octahedral cobalt(III) complexes [Co(HL)(NO₂)₃] · H₂O (1) and [Co(HL)₂](PF₆)₃ (2) were synthesized. The X-ray analysis of (1) showed that the complex has a mer-octahedral configuration formed by coordination of the tridentate ONO neutral Schiff-base molecule and three monodentate N-bonded NO₂ groups. Hydrogen bonds and intermolecular interactions for this complex are discussed. Complex (2) also has a mer-octahedral configuration. The ligand and complexes were characterized by elemental analysis, conductometric and magnetochemical measurements, IR and UV–Visible, ¹H and ¹³C NMR spectra.     

Synthesis and X-ray crystal structure of a bis-cyclometalated phosphorescent red-emitting iridium(III) complex

The synthesis of the bis-cyclometalated complex [{Ir(μ-Cl)(ccpz)₂}₂] (1, cppz = 1-chloro-4-(4-chlorophenyl)-phthalazine) from hydrated iridium(III) chloride and the ligand ccpz in refluxing ethoxyethanol is described. Compound 1 was characterized by spectroscopic means and the crystal structure was determined by X-ray crystallography. The absorption and emission spectra exhibit the new compound as a red-emitting phosphorescent complex.     

Synthesis,crystal structures and cytotoxic activity of mononuclear nickel(II) and dinuclear zinc(II) complexes with ligand derived from S-benzyldithiocarbazate

Ni(L)₂ (1) and Zn₂(μ-OL)₂(L)₂ (2), (HL = S-benzyl-β-N-(2-bromobenzylidene) dithiocarbazate), were synthesized and characterized by elemental analysis and X-ray single-crystal diffraction analysis. 1 is a mononuclear neutral nickel(II) complex and the center nickel atom is chelated by donors of N₂S₂ possessing a distorted tetrahedral configuration, while in 2, the adjacent two complex molecules are linked through two O atoms to form a dimer and the center zinc atom is five-coordinate in a distorted trigonal–bipyramidal geometry. The cytotoxic activity study indicated that 2 showed potent cytotoxic activity against the human liver hepatocellular carcinoma (HepG2) cancer cell lines, with IC₅₀ 2.4 ± 0.2 μg·mL^− 1, which is slightly weaker than 5-fluoroacil (5-FU) (0.89 ± 0.21 μg·mL^− 1) as reference. A gel electrophoresis assay demonstrated the ability of the complex to cleave the pBR322 plasmid DNA.     

Synthesis,characterization and molecular structure of Re(III) complexes containing 2-benzoylpyridine

The paper presents a combined experimental and computational study of Re(III) complexes containing 2-benzoylpyridine (bopy). Two novel complexes [ReX₃(bopy)(PPh₃)] (X = Cl, Br) have been obtained in the reactions of [ReX₃(MeCN)(PPh₃)₂] with 2-benzoylpyridine in dichloromethane and have been studied by IR, UV–Vis spectroscopy and X-ray crystallography. The electronic structure of [ReCl₃(bopy)(PPh₃)] has been calculated with the density functional theory (DFT) method. The spin-allowed electronic transitions of [ReCl₃(bopy)(PPh₃)] have been calculated with the time-dependent DFT method and the UV–Vis spectrum has been discussed on this basis.     

Synthesis and crystal structure of a mononuclear Ni(II) complex with tetraazadiphenol macrocycle bearing cyclohexanes

The mononuclear tetraazadiphenol macrocyclic nickel(II) complex [Ni(H₂[20]-DCHDC)](ClO₄)₂ (II) {H₂[20]-DCHDC = 14,29-dimethyl-3,10,18,25-tetraazapentacyclo-[25,3,1,0^4,9,1^12,16,0^19,24] ditriacontane-2,10,12,14,16(32),17,27(31),28,30-decane-31,32-diol} has been synthesized by self-assembly and characterized by elemental analysis, conductance, IR and FAB-MS spectrum, and single crystal X-ray diffraction. In the mononuclear complex, the Ni(II) ion is coordinated with a square planar conformation by two phenolate groups and two iminic sites on one side of the macrocycle. The bond angles of O–Ni–O {85.37(19)°} and N–Ni–N {88.0(2)°} are smaller than 90°.     

Removal of chromium (III) and cadmium (II) from aqueous solutions

Chromium and cadmium are toxic heavy metals present in wastewaters from a variety of industries. A strong cationexchange resin, Amberlite IR 120, was used for the removal of chromium and cadmium. The resin was prepared in two different cationic forms, as Na⁺ and H⁺. The optimum conditions were concentration, pH, stirring time and resin amount. The concentration range was between 2–50 mg/L, pH range between 2–10, stirring time between 5–60 min, and the amount of resin was from 50–1000 mg. Exchange capacities, moisture content and optimum conditions of this resin were determined in a batch system. The stirring speed was 2000 rpm during all of the batch experiments. The initial and final chromium and cadmium amounts were determined by atomic absorption spectrophotometry. The optimum conditions were found to be a concentration of 20 mg/L, pH of 5.5, stirring time of 20 min and 100 mg of resin. The results obtained show that the Amberlite IR 120 strong cation-exchange resin performed well for the removal and recovery of chromium and cadmium.