Structure and catalytic activity of host–guest coordination polymers constructed from copper(I) cyanide nets and 1,4-diaminobutane or 1,5-diaminopentane in the presence of water

The reaction of K₃[Cu(CN)₄] and 1,4-diaminobutane (DAB) or 1,5-diaminopentane (DAP) in the presence of Me₃SnCl affords two monometallic host–guest Cu(I) cyanide polymers: {[H₂DAB][Cu₄(CN)₆]·2H₂O}, 1, and{[H₂DAP][H₃O][Cu₄(CN)₇]·2H₂O}, 2, with exclusion of Me₃Sn⁺ cation. The products were characterized by physicochemical and spectroscopic methods. The structure of 1 consists of two-dimensional hexagonal sheets of (CuCN) _n which stack along the b-axis creating honeycomb-shaped channels capable of encapsulating the protonated DAB and water molecules. The structure of 2 consists of a three-dimensional network of [Cu₄(CN)₇] with large cavities that include H₂DAP and water molecules. The rhombic minicycle [Cu₂(μ-CN)₂] fragments represent the basic building blocks of the network structure of 2. The structures of these compounds are stabilized by hydrogen bonding. The SCP 1 and SCP 2 exhibit good catalytic and photocatalytic activities for the degradation of methylene blue (MB) in the presence of H₂O₂. The efficiency of recycled SCP 1 and SCP 2 and the mechanism of degradation of MB dye were also investigated.     

Synthesis and crystal structures of two new Zn(II) coordination polymers with 4,4′-dipyridyl disulfide and dicarboxylate acid

The title compounds, Zn(C₅H₆O₄)(Dpds) · 5H₂O (I) and Zn(C₆H₈O₄)(Dpds) (II) (C₅H₈O₄ = glutaric acid, Dpds = 4,4??-dipyridyl disulfide, and C₆H₁₀O₄ = adipic acid), are two-dimensional metal-organic coordination polymers. In I, the tetrahedra coordinated Zn atoms are bridged by glutarate anions and Dpds ligand to form a 2D layer parallel to (001) plane, which are connected by the 1D water tape notated as T4(2)₅(2) to build up 3D supramolecular architecture. In II, both Dpds ligands and adipate anions act as bidentate bridges, connecting the Zn(II) centers in a tetrahedral coordination geometry into a two-dimensional (4,4) layer. Each layer polycatenates adjacent layers, exhibiting the rare combination of 2D ?? 2D parallels interpenetration.     

Influence of the size of aromatic chelate ligands on the one-dimensional structures of copper(II) 4,4′-oxy-bis(benzoate) coordination polymers

Two one-dimensional coordination polymers, [Cu(Oba)(TATP)] _n · nH₂O (I) and [Cu(Oba)(DPPZ)(H₂O)]n · nH₂O (II) (Oba is 4.4′-oxy-bis(benzoate), TATP is 1,4,8,9-tetranitrogen-tris(phene), DPPZ is dipyrido[3,2-a:2′,3′-c]phenazine), have been synthesized under similar conditions and structurally characterized by elemental analysis, IR spectra, and X-ray crystal structure. Compounds I and II are based on topologically identical chains, where the copper centers chelated by the amine ligands are linked by the Oba bridges, as well as the coordination modes of the Oba ligands. However, the angles between the individual links and the environment of the copper centers are substantially different between the two compounds and were found to be primarily influenced by the sizes of the rigid aromatic chelate ligands. The article is published in the original.     

Synthesis,characterization and biological activity of copper(II) complexes with ligands derived from β-amino acids

Transition Metal Chemistry - Two copper(II) complexes with ligands derived from β-amino acids, 2-(1-aminocyclohexyl)acetic acid L1 and 2-(1-amino-4-(tert-butyl)cyclohexyl)acetic acid L2, were...     

Synthesis and characterization of chiral copper(ii) coordination polymers with 4,4´-bipyridine and lactic acid derivatives

Russian Chemical Bulletin - Chiral 2D and 3D metal-organic coordination polymers [Cu2(bpy)2(Hdml)2(HCOO)]-(HCOO)·2H2O (1) and [Cu(bpy)(Hphl)(HCOO)]·H2O (2) were synthesized by heating a...     

Structure and absorption volume for hydrogen of ultramicroporous coordination polymers of copper(II) with 4,4′-bipyridine

It was shown that the crystal structure, formed from a polymeric chain, consisting of copper(II) ions or binuclear complexes of copper(II) bonded with 4,4′-bipyridine, can contain pores, suitable for hydrogen molecules. An analysis of the sorption properties of such compounds with respect to hydrogen showed that these depend on the parameters of the pores. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 44, No. 4, pp. 233–239, July–August, 2008.     

Synthesis and X-ray crystal structures of a series of 3d–4f lanthanide complexes: lanthanide(III)–copper(II) coordination polymers with 2,5-pyridinedicarboxylic acid ligand

A series of lanthanide–transition metal (Ln–M) complexes, namely, {[Ln₂Cu(pydc)₄(H₂O)₃]·H₂O} _n (Ln = Tb, Eu, Sm or Gd) (H₂pydc = 2,5-pyridinedicarboxylic acid) have been synthesized hydrothermally by self-assembly of the lanthanide ions, copper(II) ions and 2,5-pyridinedicarboxylic acid. All the complexes were characterized by physicochemical and spectroscopic methods; in addition, structural analyses revealed that all four complexes crystallized in monoclinic space group P2₁ /c. The molecular structure contains both Cu and Ln atoms, with pydc ligands bridging the four coordinate Cu(II) centers and eight coordinate lanthanide centers to form a 3-D net structure. Hence, copper is oxidized from Cu(I) to Cu(II) during the preparation. In addition, the thermogravimetric analysis of 1 is discussed. Contrary to expectations, compounds 1–3 show no photoluminescent properties. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis,crystal structures and photoluminescence of three new Mn(II) coordination polymers assembled from 2,4′-diphenic acid

Three new metal coordination polymers, [Mn(Hdpa)₂(4,4′-bipy)₂] _n (1), [Mn(dpa)(1,10-phen)(H₂O)] _n (2), and [Mn(dpa)(2,2′-bipy)] _n (3) (H₂dpa = 2,4′-biphenyl-dicarboxylic acid, 4,4′-bipy = 4,4′-bipyridine, 1,10-phen = 1,10-phenanthroline, and 2,2′-bipy = 2,2′-bipyridine), have been synthesized and characterized by elemental analysis, IR, and X-ray diffraction. Single-crystal X-ray analyses reveal that 2,4′-diphenic acid is a bridging ligand, exhibiting three coordination modes to link metal ions: μ ₁-η ¹: η ¹/μ ₀-η ⁰: η ⁰; μ ₂-η ²: η ⁰/μ ₁-η ¹: η ⁰; and μ ₂-η ¹: η ¹/μ ₂-η ¹: η ¹. Intermolecular hydrogen bonds in 1 lead to a zigzag chain. In 2, the 2-D supramolecular arrays extended along b-axis through π–π interactions between 1,10-phen. The dinuclear paddle-wheel second building units (SBUs) constructed by four dpa^2? ligands in 3 are linked by dpa^2? into double-strand chains. The fluorescence of H₂dpa and 1–3 are also determined.     

Synthesis of copper(II) and zinc(II) complexes with chalcone–thiosemicarbazone hybrid ligands: X-ray crystallography,spectroscopy and yeast activity

Four chalcone–thiosemicarbazones (C-TSCs) of the type 2-((E)-3-(4-R-phenyl)-1-phenylallylidene)-N-phenylhydrazinecarbothioamide, where R?=?Cl (HL1), NO₂ (HL2), CH₃ (HL3) or CN (HL4), were prepared in good yields from the reaction of the respective chalcone with 4-phenyl-3-thiosemicarbazide and HCl in EtOH. Reaction of HL with CuCl₂·2H₂O or ZnCl₂ in the presence of Et₃N afforded the complexes [M(L)₂], M?=?Cu(II) or Zn(II). X-ray diffraction analysis revealed that the ligands coordinate in their deprotonated form, in a bidentate fashion through the iminic nitrogen and sulfur atoms. Yeast activities of the compounds were tested, where the ligand HL4 was the most damaging derivative, exhibiting cell viability at about 50%. On the other hand, lipid peroxidation assays revealed that the ligand HL1 was able to better induce membrane damage compared to the other compounds. It has been found that coordination with Cu(II) and Zn(II) did not increase the biological activities of the C-TSCs.     

Synthesis and structure of novel copper(II) complexes with pyrazole derived ligands and metal–ligand interaction in solution

Two new ligands of the coumarin type have been synthesized and characterized by ¹H, ¹³C NMR, IR and MS. The crystal and molecular structures of ligand 2, determined by the X-ray diffraction method, are presented. With copper(II) these ligands create solid complexes of the type CuLCl₂, where L is 5-(2-hydroxybenzoyl)-3-methyl-1-(2-pyridinyl)pyrazol-4-carboxylic acid methyl ester (2) or 3-methyl-1-(2-pyridinyl)-1H-chromene[4,3-c]pyrazol-4-on (3). The new copper(II) complexes have been characterized by elemental analysis and solid state FT-IR. The protonation constants of ligands 2 and 3 have been determined in 5% v/v 1,4-dioxane–water solution (25 °C). The coordination modes in the complexes with copper(II) are discussed for 2 on the basis of potentiometric and UV–Vis data.     

Synthesis,structures and magnetic properties of four 3D heterometallic cobalt(II)–barium(II) coordination polymers

Four heterometallic complexes, namely {[CoBa(2,5-pdc)₂(H₂O)₃]_n·2nH₂O} (1), [CoBa(2,5-pdc)₂(H₂O)₄]_n (2), [CoBa(2,5-pdc)₂(H₂O)₅]_n (3) and [CoBa₂(2,5-pdc)₃(μ₂-H₂O)₂(H₂O)₄]_n (4) (2,5-H₂pdc?=?pyridine-2,5-dicarboxylic acid), have been hydrothermally synthesized and characterized both structurally and magnetically. All four complexes exhibit 3D frameworks, in which the Co(II) centers are chelated by pyridine nitrogen and carboxyl oxygen atoms in a five-membered ring. The Ba(II) centers are chelated and bridged by carboxyl oxygen atoms to extend the structures into 3D frameworks. The networks of the complexes can be controlled via rationally choosing the appropriate ligand and tuning the ratio of the two types of metal centers. The magnetic properties of complexes 1, 2 and 4 have been investigated from 2 to 300 K.     

Crystal structures and spectroscopic properties of copper(II)–dipicolinate complexes with benzimidazole ligands

The syntheses, crystal structures and spectroscopic properties of three Cu(II)–dipicolinate complexes with benzimidazole ligands, namely [Cu(bzim)(dipic)(MeOH)] (1), [Cu₂(2-Etbzim)₂(dipic)₂]_n·0.5nH₂O (2) and [Cu₂(2-ⁱPrbzim)₂(dipic)₂]_n (3), where dipic?=?dipicolinate, bzim?=?1-H-benzimidazole, 2-Etbzim?=?2-ethyl-1-H-benzimidazole and 2-iPrbzim?=?2-isopropyl-1-H-benzimidazole, are reported. Crystal structure studies revealed different coordination modes of the dipicolinate ligands; tridentate chelating for monomeric complex 1, and both tridentate chelating and bridging for similar polymeric complexes 2 and 3. Polymers 2 and 3 both contain two units, in which the Cu(II) central atoms Cu1 and Cu2 have different coordination polyhedra. The first unit {Cu(dipic)₂} with Cu1 is connected to the second via two bidentate carboxylate groups of an μ₃-bridging dipicolinate. In the second unit, Cu2 is coordinated by two imidazole nitrogen atoms from 2-ethyl-1-H-benzimidazole (2) or 2-isopropyl-1-H-benzimidazole (3) ligands. Complex 2 is of higher symmetry and has a localized Cu(II) atom Cu2 in a special position on the twofold axis. EPR spectra of all three Cu(II) complexes, which were measured at both room temperature and 98 K, indicate distorted tetragonal coordination spheres for all the Cu(II) atoms. The g-factor relation (g_//>?g_┴?>?2.0023) is consistent with a \(d_{{x^{2} - y^{2} }}\) ground electronic state in each case.     

Determination of intermolecular copper–copper distances from the EPR half-field transitions and their comparison with distances from X-ray structures: applications to copper(II) complexes with biologically important ligands

An EPR method involving measurement of half-field transitions was applied to determine the intermolecular Cu–Cu distances in copper(II)-carboxylate complexes with biologically important ligands. The experimental powder EPR spectra are composed of allowed (ΔM _S  = ±1) transitions centered at ~3,200 Gauss and of weak intensity, nominally forbidden, half-field (ΔM _S  = ±2) peaks observable at ~1,600 Gauss. Values of the average interspin distance for each complex were determined from the ratios of integrated allowed and forbidden peak areas using each of several methods. The calculated interspin distances were correlated with the copper–copper distances experimentally obtained by X-ray crystallography. The distances determined from the EPR spectra agree well with the X-ray determined values when the crystallographic value for one member of a series is used to calibrate the series. Less satisfactory agreement is found when methods based on Cu-spin-label systems are used.     

Synthesis, structural characterisation and thermal decomposition studies of some 2,4′-bipyridyl complexes with cobalt(II), nickel(II) and copper(II)

2,4-Bipyridyl (2,4-bipy orL) complexes with cobalt(II), nickel(II) and copper(II) of the formulae M(2,4-bipy)₂(CH₃COO)₂·2H₂O (M(II) = Co, Ni, Cu), Co(2,4-bipy)₂SO₄·3H₂O or Ni(2,4-bipy)₂SO₄·4H₂O have been prepared and their IR and electronic (VIS) spectra are discussed. The thermal behaviour of the obtained compounds has also been studied. The intermediate products of decomposition at different temperatures have been characterized by chemical analysis and X-ray diffraction.We thank dr. A. Malinowska for performing VIS spectra. This work was supported by the KBN project No. PB 0636/P3/93/04.     

Coordination chemistry and biological activity of nickel(II) and copper(II) ion complexes with nitrogen–sulphur donor ligands derived from S-benzyldithiocarbazate (SBDTC)

A bidentate and a quadridentate Schiff base having NS and NNSS donor sequences were prepared by condensing S-benzyldithiocarbazate (NH₂NHCSSCH₂Ph) with 2,3-butanedione (1:1 and 1:2 mole ratio). Ni^II and Cu^II complexes of these ligands were studied and characterised by elemental analyses and various physico-chemical techniques. The nickel complexes, [Ni(NS)₂] and [Ni(SNNS)], were diamagnetic with square-planar and five-coordinate structures, respectively. The copper complex was, however, pentacoordinated. The ligands and the complexes were screened for anticancer activity against T-lymphoblastic leukemic cells (CEM-SS) and colon cancer cells (HT-29). The NS Schiff base was strongly active against leukemic cells with a CD₅₀ value of 2.05 g cm^–3. The nickel and copper complexes were found to be stronger antioxidants than Vitamin E.     

Synthesis,characterisation and electrochemical study of 4,4′-bis(salicylideneimino) diphenylethane and its complexes with cobalt(II), copper(II) and cadmium(II)

We have prepared and characterised a new series of metal complexes obtained from 4,4-bis(salicylideneimino)diphenylethane (saldipH₂) and cobalt(II), copper(II) and cadmium(II) chlorides. In every case, the coordinating atoms are N and O. However, each compound has its own structure:[Co(saldip)]·2 H₂O is monomeric and a mononuclear species, [Cu₂(saldip)₂(H₂O)] is a binuclear complex and finally the cadmium complex is formulated as:[(CdCl₂)₂(saldipH₂)]·CdCl₂. An electrochemical study (cyclic voltammetry) indicates that the reduction, as well as the oxidation, of copper in [Cu₂(saldip)₂(H₂O)] proceeds in two steps. For the reduction of the two other complexes, two steps are indicated out: the first is attributed to the reduction of the metal and the second to the reduction of the coordinated ligands.     

Three new polyoxoniobates constructed from Lindqvist-type hexaniobate and copper–amine complexes

Three new polyoxoniobates constructed from Lindqvist-type [Nb₆O₁₉]^8? and copper–amine complexes, [Cu(1,2-dap)₂]{[Cu(1,2-dap)₂]₂[Nb₆O₁₉H₂]}?·?10H₂O (1), [Cu(1,3-dap)₂]₂{[Cu(1,3-dap)]₂[Nb₆O₁₉]}?·?10H₂O (2), and [Cu(en)₂]_0.5{[Cu(en)₂]₂[Nb₆O₁₉H₃]}?·?12H₂O (3) (1,2-dap?=?1,2-diaminopropane, 1,3-dap?=?1,3-diaminopropane, and en?=?ethylenediamine), have been synthesized and characterized by elemental analyses, infrared, powder X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectrum, and single-crystal X-ray diffraction. Compounds 1–3 exhibit bisupporting hexaniobate cluster structure, each with a [Nb₆O₁₉]^8? cluster decorated by two copper–amine complexes. In 1, adjacent bisupporting clusters are connected with one [Cu(1,2-dap)₂]²⁺ fragment via Cu?···?O weak interactions to generate a 1-D supramolecular chain structure. In contrast to 1, each bisupporting cluster in 2 is linked to another four neighboring ones through four [Cu(1,3-dap)₂]²⁺ fragments by Cu?···?O weak interactions to yield a 2-D supramolecular network. Different from 1 and 2, no detected interaction was found between bisupporting cluster and [Cu(en)₂]²⁺ in 3, the [Cu(en)₂]²⁺ fragment merely acts as an isolated countercation.     

Synthesis and X-ray structure of platinum(II), palladium(II) and copper(II) complexes with pyridine–pyrazole ligands: Influence of ligands’ structure on cytotoxic activity

The new pyrazole ligand 5-(2-hydroxyphenyl)-3-methyl-1-(2-pyridylo)-1H-pyrazole-4-phosphonic acid dimethyl ester (2a) has been used to obtain a series of platinum(II), palladium(II) and copper(II) complexes (3a–7a) as potential anticancer compounds. The molecular structures of the platinum(II) and copper(II) complexes 3a and 6a have been determined by X-ray crystallography. The cytotoxicity of the phosphonic ligand 2a and its carboxylic analog 2b as well as their complexes has been evaluated on leukemia and melanoma cell lines. Copper(II) complexes were found to be more efficient in the induction of melanoma cell death than the platinum(II) or palladium(II) complexes. Cytotoxic effectiveness of compound 7b against melanoma WM-115 cells was two times better than that of cisplatin. The reaction of compound 5b with 9-methylguanine has been studied.