The synthesis and structural characterisation of the first gallium(II) dialkylphosphide complex

The reaction of a dialkyl phosphine–gallium(II) iodide complex, [Ga₂I₄{P(H)Cy₂}₂], Cy = cyclohexyl, with Et₃N has been studied. This leads to proton abstraction from the phosphine ligand and formation of the first gallium(II)–phosphide complex, [Et₃NH]₂[Ga₄I₈(PCy₂)₂], the X-ray crystal structure of which reveals an unprecedented Ga₄P₂ heterocycle.     

Formation of an unusual copper(II) complex from the degradation of a novel tricopper(II) carbohydrazone complex

An unusual copper(II) complex [Cu(L^1a)₂Cl₂] CH₃OH·H₂O·H₃O⁺Cl⁻ (1a) was isolated from a solution of a novel tricopper(II) complex [Cu₃(HL¹)Cl₂]Cl₃·2H₂O (1) in methanol, where L^1a is 3-(2-pyridyl)triazolo[1,5-a]-pyridine, and characterized with single crystal X-ray diffraction study. The tricopper(II) complex of potential ligand 1,5-bis(di-2-pyridyl ketone) carbohydrazone (H₂L¹) was synthesized and physico-chemically characterized, while the formation of the complex 1a was followed by time-dependant monitoring of the UV–visible spectra, which reveals degradation of ligand backbone as intensity loss of bands corresponding to O → Cu(II) charge transfer.     

A novel one-dimensional nickel(II) complex with a hydrogen-bond-link

A novel compound [Ni(L)(H₂O)₂]_0.5[Ni(L)(WO₄)₂]_0.5·4H₂O (1) (L=3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0^1.18,0^7.12]docosane) has been structurally and magnetically characterized. The nickel(II) ions are shown to be in distorted octahedral environments with secondary amines of macrocycles in which two trans water molecules and two trans tungstate ions are assembled around each metal center. Two nickel(II) complexes are connected into a one-dimensional chain via hydrogen bonds. The magnetic susceptibility measurement for 1 indicates weak antiferromagnetic interaction (J=−1.01(2) cm⁻¹; H=−JΣS_i·S_i+1) between the S=1 nickel(II) paramagnetic centers.     

Dinuclear copper(II) complex with tetrathiafulvalene-based bis-acetylacetonate ligands

Deprotection of the cyanoethyl groups with 2 equivalents of the strong base (CsOH) and subsequent reaction with the electrophilic 3-chloro-2,4-pentanedione afford the bis(acetylacetone)tetrathiafulvalenes, trans- and cis-acac₂. The formation of the dinuclear rectangle-shaped complex [Cu₂(cis-acac₂)₂ 2DMF 2H₂O] (1), demonstrates the chelating ability of the interesting TTF-acetylacetonate ligand. Cyclic voltammetry experiments have evidenced the two one-electron steps to the radical cation and dication species of the new ligand, and the two quasi-reversible two-electron oxidation processes of complex 1.     

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.     

A novel chloro-bridged tetranuclear cadmium(II) cluster with pyridyl-substituted nitronyl nitroxide: structure and magnetic properties

A tetranuclear cadmium(II) complex of 2(2-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1 H-imidazol-1-oxy 3-N-oxide (NIToPy) with CdCl₂,[Cd₄Cl₈(NIToPy)₄], has been structurally and magnetically characterized. The structure is based on a novel chloro-bridged tetranuclear cadmium quasi-cubane cluster, in which each cadmium atom is chelated by one NIToPy radical, and coordinated with four bridging chlorine atoms. The temperature dependence of the magnetic susceptibility measurements shows a weak ferromagnetic coupling between the radicals. An excellent simulation of the experimental data with the prism type four spins Hamiltonian H=−2J₁(S₁S₂+S₂S₃+S₃S₄+S₁S₄)−2J₂S₂S₄ obtained the parameters: J₁=1.12 cm⁻¹, J₂=−0.20 cm⁻¹, and g=2.04.     

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.     

Reactions of bis(3-aminopropyl)amine with formaldehyde in the presence of a metal ion: Preparation of a metal-free macropolycycle and a dinuclear copper(II) complex

The reaction of bis(3-aminopropyl)amine with excess formaldehyde in the presence of Ni²⁺ ion produces the macropentacyclic compound L¹(ClO₄)₂ (1) L¹ = 1,3,7,11,13,17- hexaazapentacyclo[15.3.1.1^3.7.1^7.13.1^13.17]tetracosane). The dinuclear complex [Cu₂(L²)₂(H₂O)₂](ClO₄)₂ (2) (HL¹ = 1-(3-aminopropyl)-3-(hydroxymethyl)-1,3-diazacyclohexane) as well as 1 can be prepared by the condensation reaction in the presence of Cu²⁺ ion. Interestingly, 2 · 2H₂O exhibits uncommon magnetic behavior.     

Preparation,Crystal Structure,Thermal Decomposition,and Explosive Properties of [Cd(en)(N3)2]n

A new multi‐ligand coordination polymer of cadmium(II) ethylenediamine azide, [Cd(en)(N₃)₂]_n (en=ethylenediamine), was synthesized and characterized by using elemental analysis and FT‐IR spectrum. Its crystal structure was determined by means of X‐ray single crystal diffraction. The obtained results show that this crystal belongs to monoclinic, P2₁/n space group, a=0.6548(1) nm, b=1.0170(2) nm, c=1.2246(2) nm, β=90.23(1)°, V=0.8156(2) nm³, D_c=2.090 g⋅cm⁻³, Z=4, R₁=0.024, wR₂ (I>2σ(I))=0.0416 and S=0.998. The Cd(II) ion is six‐coordinated with four azido ligands by μ‐1, 1 azido bridges, and two ethylenediamine molecules which serve as bidentate ligands through the nitrogen atoms. The thermal decomposition mechanism of the title complex was studied by using differential scanning calorimetry (DSC) and thermogravimetry‐differential thermogravimetry (TG–DTG) techniques. Under nitrogen atmosphere with a heating rate of 10 K⋅min⁻¹, the thermal decomposition of the complex contains two main successive exothermic processes between 519 and 701 K in the DSC curve, and the final decomposed residue at 725 K is Cd. The non‐isothermal kinetics parameters were calculated by using the Kissinger's method, Ozawa–Doyle's method, pervasive integration method, and differential method, respectively. The sensitivity properties of [Cd(en)(N₃)₂]_n were also determined with standard methods.     

Synthesis and structural characterisation of unprecedented dinuclear zinc(II) complex with H-bonded bridging phthalate ions

An extremely unusual dimer [(bpy)₂Zn(Pht)H(Pht)Zn(bpy)₂)](HPht)(H₂Pht)·2H₂O (1) (where Pht²⁻=dianion of o-phthalic acid, bpy=2,2^′-bipyridine) in which [Zn(bpy)₂] metal cores are connected through Pht⋯H⋯Pht bridge has been synthesised and its structure determined by X-ray crystallography.     

Structural correlations in nickel(II)–thiodiacetato complexes: molecular and crystal structures and properties of [Ni(tda)(H2O)3]

Triaqua(thiodiacetato)nickel(II) has been synthesized and studied by X-ray crystallography, thermal, spectral and magnetic methods. The compound crystallizes in the triclinic system, space group , in contrast to the related compound [Ni(tda)(H₂O)₃] · H₂O (orthorhombic) reported long time ago. As in other four Ni–tda derivatives, the metal atom exhibits an octahedral coordination and tda ligand adopts a fac-tridentate chelating role. The studied compound is closely related to [Zn(tda)(H₂O)₃]. In addition, a structural comparison of the binary and ternary Ni–tda derivatives reveals that auxiliary N-donor ligands bind the metal atom using the trans-positions towards the Ni–O(carboxylato) bonds, but not in trans to the Ni–S(thioether) bond.     

Synthesis, structure and magnetic properties of a novel lead(II) complex containing nitronyl nitroxide radicals

The lead(II) complex with nitronyl nitroxide, [Pb(NIT2Py)₂(NO₃)₂] [NIT2Py = 2-(2′-pyridyl)-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, the lead(II) ion is coordinated with two bidentate nitronyl nitroxide and two nitrate anions. The lead(II) ion shows seven-coordinate geometry. Magnetic susceptibility data for the title complex has been measured in the range 5–300 K. There are antiferromagnetic interaction between the coordinated nitronyl nitroxides (J = −19.35 cm⁻¹) and intermolecular ferromagnetic interactions. Thus, we observe the sixth periodic IVA group metal element Pb(II) ion providing an effective pathway for the magnetic exchange interaction between nitronyl nitroxide radicals.     

Structural characterisation of rac-bis(2,2-bipyridine)(2,5-dipyridylpyrazine)ruthenium(II) hexafluorophosphate; a key building block for metallodendrimers

The complex [(bipy)₂Ru(dpp)][PF₆]₂ which contains a vacant 2,2^′-bipyridine-like metal-binding domain has been structurally characterised. This compound is a key building block for the construction of metallodendrimers using the “complexes as metals, complexes as ligands” approach.     

Synthesis, Characterization and Thermal Studies of Zn(II), Cd(II) and Hg(II) Complexes of N-Methyl-N-Phenyldithiocarbamate: The Single Crystal Structure of [(C(6)H(5))(CH(3))NCS(2)](4)Hg(2)

Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate have been synthesized and characterized by elemental analysis and spectral studies (IR, (1)H and (13)C-NMR). The single crystal X-ray structure of the mercury complex revealed that the complex contains a Hg centre with a distorted tetrahedral coordination sphere in which the dinuclear Hg complex resides on a crystallographic inversion centre and each Hg atom is coordinated to four S atoms from the dithiocarbamate moiety. One dithiocarbamate ligand acts as chelating ligand while the other acts as chelating bridging ligand between two Hg atoms, resulting in a dinuclear eight-member ring. The course of the thermal degradation of the complexes has been investigated using thermogravimetric and differential thermal analyses techniques. Thermogravimetric analysis of the complexes show a single weight loss to give MS (M = Zn, Cd, Hg) indicating that they might be useful as single source precursors for the synthesis of MS nanoparticles and thin films.     

Novel Cd(II) and Co(II) 2-D frameworks based on terephthalate and 1-substitutedimidazole mixed-ligands

The two Cd(II) and Co(II) 2-D frameworks have been prepared by means of self-assemblies of Cd(II) or Co(II) salts and 1-substituted imidazole and terephthalic acid, and structurally characterized by X-ray diffraction analyses. In complex 1 2-D frameworks with rhombic cavity are formed, in which the each top point of rhombus contains one hexa and two heptacoordinated Cd(II). In complex 2 2-D networks with rectangular cavities are formed, and the opposite benzene rings from carboxyls in each rectangular cavity are parallel.     

Simultaneous preconcentration of Cd(II), Cu(II) and Pb(II) on Nano-TiO2 modified with 2-mercaptobenzothiazole prior to flame atomic absorption spectrometric determination

Nano-TiO₂ modified with 2-mercaptobenzothiazole (MBT) was investigated as a new adsorbent for preconcentration of Cd(II), Cu(II) and Pb(II). The metal ions are adsorbed onto nano-TiO₂-MBT, eluted by nitric acid and determined by flame atomic absorption spectrometry. The parameters affecting the adsorption were investigated. Under optimized conditions, the calibration curves were linear in the range of 0.2–25.0, 0.2–20.0, and 3.0–70.0 ng mL⁻¹ for cadmium, copper and lead, respectively. The limits of detection for Cd(II), Cu(II) and Pb(II) were 0.12, 0.15 and 1.38 ng mL⁻¹, respectively. The method was applied to determination of Cd(II), Cu(II) and Pb(II) in water and ore samples.     

双(咪唑啉-2-亚胺)吡啶钯配合物的合成及其配位结构的研究

合成了一种未见报道的新型双(咪唑啉-2-亚胺)钯配合物,在合成过程中优化了传统的原料合成路线,得到的配体通过1H NMR进行了表征,配体结构中含有两个具有强推电子效应的氮杂环卡宾,钯配合物的空间配位结构通过X-Ray单晶衍射分析确定。单晶分析结果显示,该配合物的金属中心与三个氮原子配位,原本与金属原子相连的氯原子从金属中心脱落,以配位的形式存在于配合物晶体的晶胞结构中,咪唑啉环所在平面与吡啶环平面呈接近九十度的夹角,使得咪唑啉环很好的包围了金属中心。     

Preparation and characterisation of dipotassium trizinc hexacyanoferrate (II)

This paper summarises our findings on the properties and cation exchange behaviour of a new silica-based dipotassium trizinc hexacyanoferrate (II) (DTH) prepared under varying conditions of precipitation which possesses good ion-exchange properties. The product is characterised by i.r. spectra, thermal decomposition, X-ray diffractogram and its ion-exchange properties have been studied under different conditions. The separation of Rb⁺ and Cs⁺ is described.     

Metal chelates with some cellulose derivatives. Part III. Synthesis and structural chemistry of nickel (II) and copper (II) complexes with carboxymethyl cellulose

Cu(II) and Ni(II) complexes with three grades of carboxymethyl cellulose (CMC) with different degrees of substitution have been synthesized and characterized. Probable structures of the metal complexes are inferred from the electronic and IR spectra, elemental analysis data and magnetic moment measurements. CMC coordinates with cu(II) and Ni(II) via the carboxymethyl and hydroxyl groups. The effect of the degree of substition of the CMC on the mode of chelation is discussed. Ni(II) complexes show an octahedral geometry around the metal ion and exhibit the formula [NiL · 4H₂O]Cl. Cu(II) complexes exist in the square planar form and have the formula Cu(L)₂, where L is uninegatively charged bidentate CMC ligand. The ligand field parameters of Ni(II) complexes are also evaluated.