Copper(II) complexes with 4-(3,5-dimethyl-1H-pyrazol-1-yl)-2-methyl-6-phenylpyrimidine: Syntheses, crystal structures and catalytic activity in ethylene polymerization

The copper(II) complexes CuLCl₂ (1) and CuLBr₂ (2), with the chelating pyrazolylpyrimidine ligand 4-(3,5-dimethyl-1H-pyrazol-1-yl)-2-methyl-6-phenylpyrimidine (L), have been synthesized. A single crystal X-ray diffraction study revealed that 1 and 2 have molecular mononuclear structures. The molecules of 1 and 2 form chains in the crystal structures of these compounds due to the formation of π-π-stacking interactions between the pyrimidine and the phenyl rings. The complexes, in combination with the co-catalyst methylaluminoxane (MAO), reveal catalytic activity in ethylene polymerization, while the free ligand L is inactive.     

Copper(II) complex with 2-(diphenylacetyl)indanedione-1,3: Synthesis and structure

A copper(II) complex with 2-(diphenylacetyl)indanedione-1,3 (HL) was synthesized. CuL₂·0.5C₄H₈O₂ crystals prepared from chloroform + 1,4-dioxane are triclinic, space group P \(\bar 1\), a = 15.0206(9) Å, b = 16.0132(9) Å, c = 16.8323(10) Å, α = 109.6850(10)°, β = 96.4390(10)°, γ = 97.7120(10)°, Z = 4. A unit cell contains two crystallographically independent centrosymmetric dinuclear complexes of the same structure. Each copper(II) atom is coordinated by bidentate cis-oriented deprotonated ligands L at the corners of the square. Bridging 1,4-dioxane molecules make the CN of each metal atom five.     

Synthesis,characterization and crystal structures of new Zinc(II) and Nickel(II) complexes containing morpholine moiety and their antibacterial studies

The ligand 1,2-dimorpholinoethane (DME) was used to prepare Zn(II) and Ni(II) complexes of the general formulation MLX₂ (L = DME, X = Cl or NO₃). Zinc(II) complex exhibits spectral properties indicative of a distorted tetrahedral geometry, with DME coordinating through two nitrogen atoms and two chlorides completing the tetrahedron. This is in contrast to the six-coordinated, distorted octahedral geometry exhibited by nickel(II) complex of DME when NO₃ was used as counter ions. The X-ray diffraction confirms the structures of two complexes and shows that the ligand coordinates through two nitrogen atoms while the two ether linkages are not involved in complexation, which would have been the case if the morpholine rings were in the boat form. The ligand and related complexes have antibacterial activity against the five Gram-positive bacteria: Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6538, Bacillus cereus NRRL-B-3711, Enterococcus faecalis ATCC 29212 and Streptococcus pyogenes and also against the three Gram-negative bacteria: Escherichia coli ATCC 11230, Pseudomonas aeruginosa ATCC 15442 and Klebsiella pneumonia ATCC 70063. The results showed that in some cases the antibacterial activity of the complexes exceeded the one of sulfisoxazole used as a standard.     

Synthesis and structure of (bis(3,5-dimethyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-yl)methane)diiodocobalt(II)

A cobalt(II) iodide complex with bis(3,5-dimethyl-1H-pyrazol-1-yl)methane (L) CoLI₂ has been synthesized, and its single crystals have been obtained. The complex compound was characterized by electron spectroscopy and X-ray diffraction analysis. The compound crystallizes in the monoclinic system (a = 8.4044(4) Å, b = 13.3120(5) Å, c = 14.5824(7) Å; β = 94.7290(10)°; V = 1625.92(13) ų; Z = 4; ρ^calc = 2.112 g/cm³; space group P2₁/m). The structure of the complex is molecular mononuclear. L is a cyclic bidentate ligand; the coordination polyhedron of cobalt is a CoN₂I₂ tetrahedron formed by the nitrogen atoms of the pyrazole fragments L and iodine atoms. The complex has π-π stacking interactions between the pyrazole rings of CoLI₂ molecules, binding the molecules into infinite chains along the b axis.     

New metal chelates of 5-amino-4-azopyrazoles: The crystal and molecular structure of bis{1-phenyl-3-methyl-4-(<Emphasis Type="Italic">p</Emphasis>-tolyl)azo-5-(<Emphasis Type="Italic">p</Emphasis>-carboxymethoxyphenyl)pyrazolamidato}copper(II)

The reactions of 1,3-alkyl(aryl) derivatives of 5-amino-4-azopyrazoles (HL) with copper(2+) acetate afford metal chelates CuL₂. Complexes with the CuN₄ chromophore containing a substituted amino group (X = NR) as a donor, like their azomethine analogues, have a pseudotetrahedral structure. Copper chelates with X = NH are planar. The X-ray diffraction data and an additional hyperfine structure (ahfs) from ¹⁵N atoms of the azo group in the labeled complexes provide evidence for the formation of six-membered metallocycles. The coordination polyhedron in bis{1-phenyl-3-methyl-4-(p-tolyl)azo-5-(p-carboxymethoxyphenyl)pyrazolamidato}Cu(II) can be described as a pseudotetrahedron.     

Synthesis,structures and magnetic properties of three copper(II) complexes of 2-(1<Emphasis Type="Italic">H</Emphasis>-pyrazol-3-yl) pyridine

Three Cu(II) complexes: [Cu₂(μ-L)₂(HCOO)₂(H₂O)₂] (1), [Cu₂(μ-L)₂(NO₃)₂] (2), and [Cu₄(μ-L)₆(CH₃COO)₂]·2H₂O (3) constructed from 2-(1H-pyrazol-3-yl) pyridine (HL) were synthesized and structurally characterized by X-ray single-crystal diffraction. The X-ray analyses revealed that all three complexes feature a di-ligand-bridged Cu₂ unit, which is nearly planar. Each deprotonated ligand chelates one copper atom by means of N,N(pyridine-pyrazole) pocket and simultaneously bridges the other one by the N,N(pyrazole) groups. The remaining coordination sites of the Cu(II) centers are either occupied by different anionic coligands to balance the charge, or bridged by another L to develop a tetranuclear structure. Magnetic investigations reveal that the distortion of the Cu(II) coordination geometry (as described by the τ values) and the coplanarity of the Cu–(N=N)₂–Cu unit have cooperative effects on the antiferromagnetic strength of these systems.     

Copper(II) and cobalt(II) complexes with a chiral 5-pyrazolone derivative obtained from the terpene (+)-3-carene: Synthesis and properties

The complexes [CuLCl₂] (I), [CoLCl₂] (II), and CuLBr₂ (III) (where L is the derivative of optically active 5-pyrazolone prepared from the terpene (+)-3-carene) were obtained and characterized. According to X-ray diffraction data, crystal structures I and II (orthorhombic crystal system) are built from mononuclear acentric molecules. In the resulting complexes, the Cu²⁺ or Co²⁺ ion coordinates two N atoms of the chelating bidentate ligand L and two Cl atoms, thus making a distorted tetrahedron. Intermolecular contacts and the hydrogen bonds Cl(1)…H-O(1) give rise to columns parallel to axis y. For complexes I and III, μ_eff = 1.83 and 1.81 μB, respectively; these values correspond to the electronic configuration d ⁹ . For complex II, μ_eff = 4.42 μB, which suggests the tetrahedral structure of the coordination entity CoCl₂N₂. Complexes I and III were studied by EPR spectroscopy.     

Zinc(II), Cadmium(II), and Mercury(II) Complexes of 2-Methyl-benzoselenazole

The following zinc(II), cadmium(II) and mercury(II) complexes of 2-methyl-benzoselenazole (L) have been prepared and studied by conductometric and i.r. methods: MLX₂ (M ? Cd, Hg, X ? Cl, Br, I), ML_1.5X₂ (M ? Zn, X ? ClO₄(4 H₂O); M ? Hg, X ? NO₃, ClO₄), ML₂X₂ (M ? Zn, X ? Cl, Br, I, NO₃; M ? Cd, X ? NO₃, ClO₄). The ligand is N-bonded. All the anions are coordinated.     

Mechanochemical synthesis of platinum(<Emphasis Type="SmallCaps">IV</Emphasis>) complexes with <Emphasis Type="Italic">N</Emphasis>-heterocyclic carbenes

A new method for the synthesis of complexes Pt^IV(NHC)X₄L (NHC is N-heterocyclic carbene of imidazole or benzimidazole series; X = Cl, Br; L is N-coordinated pyridine or NHC) based on mechanochemical oxidation of complexes Pt^II(NHC)X₂L with dichloroiodobenzene (PhICl₂) or pyridinium hydrobromide perbromide (PyHBr₃) was proposed. Mechanochemical activation led to reduction in the synthesis time and increase in the selectivity of halogenation and yields of the target Pt^IV complexes (74–98%) as compared to the reaction in solutions.     

Palladium complexes based on optically active terpene derivatives of ethylenediamine

Novel chiral palladium diamino complexes with the asymmetric donor N atom Pd(En*)X₂ (where En* = N,N′-bis{[(1S,5R)-6,6-dimethylbicyclo[3.1.1]hept-2-en-2-yl]methyl}-1,2-ethylenediamine; X = Cl and Br) were obtained and characterized. Nitrogen-containing derivatives of the natural monoterpene a-pinene were studied as accessible optically active ligands.     

Potentiometric study of the kinetics and equilibria of formation of chloroglycinate palladium(II) complexes from bis-glycinato palladium(II) complexes

The equilibria and kinetics of the reaction of Pd(gly)₂ complexes with hydrogen ions and chloride ions has been studied by a potentiometric method. The underlying idea of the method is the measurement of solution pH as a function of reaction time t using a glass electrode. The solutions used had the following initial compositions: xM Pd(gly)₂, xM Hgly, and 1 M NaCl with x = 1 × 10^?4, 5 × 10^?4, and 1 × 10^?3; initial pH₀ was from ～3.5 to ～4.4. The experimentally determined pH versus t dependences and the rate equation for a pseudo-second-order reaction were used to determine the equilibrium constant of formation of Pd(gly)(Hgly)Cl complexes from Pd(gly)₂ complexes and the observed rate constant for this reaction, k _obs. The dependence of k _obs on the pH of the acid solutions studied was assigned to a change in the sequence of the reactions of addition of a hydrogen ion and a chloride ion to the complex Pd(gly)₂.     

Spin crossover in homo- and heteroligand iron(II) complexes with tris(pyrazol-1-yl)methane derivatives

The studies concerning coordination compounds of various salts of iron(II) with tris(pyrazol-1-yl)methane derivatives (HC(pz)₃) are discussed. The results of a number of studies on the synthesis and investigation of the homo- and heteroligand iron(II) complexes with tris(3,5- dimethylpyrazol-1-yl)methane (HC(3,5-Me₂pz)₃) are considered. The study of the temperature dependence μ_eff (T) showed that the spin crossover (SCO) ¹A₁?⁵T₂ observed in a series of the compounds discussed is accompanied by thermochromism (color change pink (purple) ? colorless). Specific features of the SCO and their dependence on the outer-sphere anion in the iron(II) complexes are discussed. The data of the recently published work devoted to the synthesis of the iron(II) complexes with three N-substituted HC(pz)₃ derivatives (general formula ^xL, where x = H, CH₂C₆H₅ (Bn) and p-SO₃C₆H₄CH₃ (Ts)) are considered.     

Syntheses and crystal structures of copper(II) and nickel(II) complexes derived from 2-bromo-4-chloro-6-[(2-methylaminoethylimino)methyl]phenol

A new centrosymmetric mononuclear copper(II) complex [Cu(L)₂](ClO₄)₂ (I) and a new centrosymmetric mononuclear nickel(II) complex [Ni(L)₂(MeOH)₂](ClO₄)₂ (II), where L is the zwitterionic ligand 2-bromo-4-chloro-6-[(2-methylammonioethylimino)methyl]phenolate, have been prepared from the Schiff base 2-bromo-4-chloro-6-[(2-methylaminoethylimino)methyl]phenol with copper perchlorate and nickel perchlorate, respectively. The complexes were characterized by elemental analysis, infrared spectra, and single-cyrstal X-ray diffraction (CIF files CCDC nos. 1408054 (I) and 1407973 (II)). Complex I crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 7.7736(4), b = 21.608(1), c = 8.5194(4) Å, β = 93.907(2)°, V = 1427.7(1) ų, Z = 2, R ₁ = 0.0546, and wR ₂ = 0.1531. Complex II crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 21.324(3), b = 16.821(2), c = 9.425(1) Å, β = 90.114(2)°, V = 3380.5(7) ų, Z = 4, R ₁ = 0.0693, and wR ₂ = 0.1627. The Cu atom in I is in square planar coordination, and the Ni atom in II is in octahedral coordination.     

Complexes of cobalt(II) halides with 2-(1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-yl)-4(3<Emphasis Type="Italic">H</Emphasis>)-pyrimidinone

The electronic structures of complexes of cobalt(II) halides with 2-(1H-pyrazol-1-yl)-4(3H)-pyrimidinone have been studied by X-ray photoelectron spectroscopy. The Co2p _3/2 lines of cobalt atoms, N1s lines of nitrogen atoms, and O1s lines of oxygen atoms in the X-ray photoelectron spectra have been analyzed. Based on these data for the free and coordinated ligands, the atoms of the ligand coordinated to the central metal atom are determined. The coordinated organic compound serves as an electron-donating ligand. The results obtained are consistent with IR and UV-Vis spectroscopic data.     

Synthesis and crystal structures of the nickel(II) complex with nitronyl nitroxide

Two nickel(II) complexes [Ni(NIT-l′-MeBzlrn)₂(Dca)₂] (I, II) (NIT-l′-MeBzIm = 2-{2′-[(l′methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide) have been prepared and structurally characterized by single-crystal X-ray diffraction. They are structural epimers. The complexe crystallizes in monoclinic, space group P2₁/n, Z = 4. Crystal data: C₃₄H₃₈N₁₄NiO₄, M _r = 765.49, a = 15.019(3), b = 18.803(4), c = 15.756(3) Å, β = 109.399(3)°, γ = 90° (I); a = 13.934(3), b = 11.046(2), c = 24.570(5) Å, β = 90.024(2)° (II). The X-ray analysis reveals that Ni²⁺ ion resides in a distorted octahedral center. The complex was linked by intermolecular hydrogen bonds, resulting in a ID chain structure for I and a 2D network configuration for II.     

New complex of manganese(II) with schiff base derived from furaldehyde and diethylenetriamine

A new manganeses(II) complex MnLCl₂ · CH₃OH (L = N,N′-bis(furaldehyde)diethylenetriamine) was synthesized and characterized by X-ray crystallographic analysis. The crystals are orthorhombic, space group Pnma with cell parameters a = 20.998(6), b = 13.314(5), c = 6.785(8) Å, Z = 4, R ₁ = 0.0609, and wR₂ = 0.2116. The coordination geometry around Mn(II) atom is a trigonal-bipyramidic containing one tridenate ligand L and two Cl^? ions.     

Molecular complexes of cobalt(II) and Zinc(II) chlorides and bromides with 1-piperidinyl dimethylcarbamodithioate (L): Crystal structures of L and [ZnLBr<Subscript>2</Subscript>]

Complexes of MX₂(M = Co, Zn; X = Cl, Br) with 1-piperidinyl dimethylcarbamodithioate (L) of composition [MLX₂] have been synthesized. The compounds have been studied by elemental analysis; X-ray diffraction; thermogravimetry; conductometry; magnetochemistry; and IR, ¹H NMR, and electronic absorption spectroscopy. The ligand molecule is coordinated to the metal atoms in a bidentate chelating mode through the thione sulfur atom and the sulfenamide nitrogen atom to form a five-membered chelate ring. The structures of L and [ZnLBr₂] have been determined by X-ray crystallography.     

Asymmetric Oxygen Bridged Copper(II) Carboxylate: Synthesis,Complete Characterization,and Crystal Structure

Binuclear centrosymmetric copper(II) complex of the formula bipyCu(L)₄Cubipy, where bipy = 2,2′- bipyridine and L = 4-methoxy-2-phenyl acetate, is synthesized and characterized by FT-IR, UV-Visible, ESR and mass spectroscopy, electrochemical, thermogravimetric, and single crystal XRD techniques. The complex contains two differently oriented molecules per unit cell stabilized via intermolecular interactions. Geometry around each Cu(II) was found to be square pyramidal affected by asymmetrically bridging oxygen atoms occupying the apical position of one square pyramid and the axial position of another in the same binuclear molecule. The square base is formed by two oxygen atoms from two carboxylate ligands and two nitrogen atoms from the bipyridine moiety. TGA shows that the complex is stable up to 170 °C followed by stepwise loss of coordinated ligands, which was supported by GC-MS data as well. A broad absorption spectrum indicated ²B_1g as the ground state and single electron occupancy of the dx²–y² orbital, which was confirmed by the ESR spectrum. The electrochemical study gives two oxidation curves corresponding to Cu(II)/Cu(III) and Cu(I)/Cu(II) and a reduction signal corresponding to the Cu(II)/Cu(I) process. The robust complex represents an interesting contribution to the understanding of coordination chemistry.     

Structural and physicochemical characterization of zinc(II) and cadmium(II) complexes with 1,4‐dimethy‐lhomopiperazine

In order to know the relationship between structures and physicochemical properties of Group 12 metal(II) ions, the complexes with ‘simple’ ligands, such as alkyl cyclic diamine ligand and halide ions, were synthesized by the reaction of 1,4‐dimethylhomopiperazine (hp′) with MX₂ as metal sources (M = Zn, Cd; X = Cl, Br, I). The five structural types, [ZnX₂(hp′)] (X = Cl ( 1 ), Br ( 2 ) and I ( 3 )), [ZnX₃(Hhp′)] (X = Cl ( 1′ ) and Br ( 2′ )), [CdCl₂(hp′)]_n ( 4 ), [{CdCl₂(Hhp′)}₂(µ‐Cl)₂] ( 4′ ) and [{CdX(hp′)}₂(µ‐X)₂] (X = Br ( 5 ), I ( 6 )), were determined by X‐ray analysis. The sizes of both metal(II) and halide ions and the difference in each other's polarizability influence each structure. All complexes were characterized by IR, far‐IR, Raman and UV–Vis absorption spectroscopies. In the far‐IR and Raman spectra, the typical ν(M N) and ν(M X) peaks clearly depend on the five structural types around 540–410 cm⁻¹ and 350–160 cm⁻¹ respectively. The UV–Vis absorption band energy around 204–250 nm also reflects each structural type. Copyright © 2005 John Wiley & Sons, Ltd.     

Copper(II) halide reactions with the - NH · CS - group in heterocyclic pentaatomic rings

Summary White crystalline complexes of general formula Cu₂L₄X₂ (where X = Cl, Br and L = 1, 3-oxazolidine-2-thione, pyrrolidine-2-thione,N-methyl-1,3-imidazolidine-2-thione andN-ethyl-1,3-imidazolidine-2-thione) and CuLX (where L = 1,3-imidazolidine-2-thione) were prepared by reduction of copper(II) halides and studied by i.r. spectroscopy in the 4000–200 cm^– range. Evidence for ligand coordination to the metal through sulphur was found in each case. The(CuCI) vibration in all the chloro derivatives falls atca. 240 cm^–.