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In this paper, carbon-matrix-supported copper (Cu) and cobaltous oxide (CoO) nanoparticles were obtained by using coordination polymers (CPs) as a precursor. The aqueous solutions of copper methacrylate (CuMA) and cobalt methacrylate (CoMA) were preferentially prepared, which were then mixed with anhydrous ethanol to fabricate dual metal ion coordination polymers (CuMA/CoMA). After calcination under an argon atmosphere, the Cu-CoO/C nanocomposite was obtained. Scanning electron microscope (SEM) and transmission electron microscope (TEM) showed that the material has banded morphology, and the dual functional nanoparticles were highly dispersed in the carbon matrix. The prepared material was used in a heterogeneous Fenton-like reaction, with the aim of replacing traditional ferric catalysts to solve pH constraints and the mass production of ferric slime. The obtained nanocomposite showed excellent catalytic performance on the degradation of methylene blue (MB) at near-neutral conditions; the discoloration efficiency is about 98.5% within 50 min in the presence of 0.15 mmol/mL H2O2 and 0.5 mg/mL catalyst. And good reusability was verified via eight cycles. The plausible pathway for MB discoloration and the possible catalytic mechanism was also proposed. [ABSTRACT FROM AUTHOR]

In this paper, the synthesis and crystal structure of pyrazine-2,5-diyldimethanol (pyzdmH2, C6H8N2O2), a new symmetric water-soluble N,O-chelating tetra-dentate organic ligand, is reported and an environmentally friendly method is used to synthesize coordination compounds in water under ambient conditions, from the reaction of pyzdmH2 with the halide salts of Cu(II), Zn(II), Hg(II) and Cd(II): {[Cu(pyzdmH2)0.5(µ-Br)(Br)(H2O)]·H2O}n 1, {[Zn2(pyzdmH2)(µ-Cl)(Cl)3(H2O)]·H2O}n 2, [Hg2(pyzdmH2)0.5(µ-Cl)2(Cl)2]n 3, {[Cd2(pyzdmH2)(µ-Cl)4]·H2O}n 4, and {[Cd2(pyzdmH2)(µ-Br)4]·H2O}n 5. Single-crystal X-ray diffraction analysis reveals that 1–3 are 1D coordination polymers and 4 and 5 are 3D coordination networks, all constructed by bridging pyrazine-2,5-diyldimethanol and halogen ions. The hydroxyl groups in the organic linker extend the 1D chains to non-covalent 3D networks. In all non-covalent and covalent 3D networks, water molecules are trapped by strong hydrogen bond interactions. Supramolecular analysis reveals strong O-H···O, O-H···N, O-H···X, and weak C-H···O, C-H···X (X = Cl, Br) hydrogen bonds, as well as π-π(pyrazine ring), metal-halogen···π(pyrazine ring), and O-H···ring(5-membered chelate ring) interactions. In addition, X···O weak halogen bonds are present in 1–5 (X = Cl and Br). [ABSTRACT FROM AUTHOR]

This paper describes the synthesis and characterization of seven different copper(II) coordination compounds, as well as the formation of a protonated ligand involving all compounds from the same reaction. Their synthesis required hydrothermal conditions, causing the partial in situ transformation of 5-fluoro uracil-1-acetic acid (5-FUA) into an oxalate ion (ox), as well as the protonation of the 4,4′-bipyridine (bipy) ligand through a catalytic process resulting from the presence of Cu(II) within the reaction. These initial conditions allowed obtaining the new coordination compounds [Cu2(5-FUA)2(ox)(bipy)]n·2n H2O (CP2), [Cu(5-FUA)2(H2O)(bipy)]n·2n H2O (CP3), as well as the ionic pair [(H2bipy)+2 2NO3−] (1). The mother liquor evolved rapidly at room temperature and atmospheric pressure, due to the change in concentration of the initial reagents and the presence of the new chemical species generated in the reaction process, yielding CPs [Cu(5-FUA)2(bipy)]n·3.5n H2O, [Cu3(ox)3(bipy)4]n and [Cu(ox)(bipy)]n. The molecular compound [Cu(5-FUA)2(H2O)4]·4H2O (more thermodynamically stable) ended up in the mother liquor after filtration at longer reaction times at 25 °C and 1 atm., cohabiting in the medium with the other crystalline solids in different proportions. In addition, the evaporation of H2O caused the single-crystal to single-crystal transformation (SCSC) of [Cu(5-FUA)2(H2O)(bipy)]n·2n H2O (CP3) into [Cu(5-FUA)2(bipy)]n·2n H2O (CP4). A theoretical study was performed to analyze the thermodynamic stability of the phases. The observed SCSC transformation also involved a perceptible color change, highlighting this compound as a possible water sensor. [ABSTRACT FROM AUTHOR]

Pyridine-alkoxide (pyalk) ligands that support transition metals have been studied for their use in electrocatalytic applications. Herein, we used the pyalk proligands diphenyl(pyridin-2-yl)methanol ([H]PhPyalk, L1), 1-(pyren-1-yl)-1-(pyridin-2-yl)ethan-1-ol ([H]PyrPyalk, L2), 1-(pyridine-2-yl)-1-(thiophen-2-yl)ethan-1-ol ([H]ThioPyalk, L3), and 1-(ferrocenyl)-1-(pyridin-2-yl)ethan-1-ol ([H]FePyalk, L4) to synthesize CuII complexes that vary in nuclearity and secondary coordination sphere. Also, the proligand 1-(ferrocenyl)-1-(5-methoxy-pyridin-2-yl)ethan-1-ol ([H]FeOMePyalk, L5) was synthesized with a methoxy substituted pyridine; however, the isolation of a CuII complex ligated by L5 was not possible. Under variable reaction conditions, the pyalk ligands reacted with CuII precursors and formed either mononuclear or dinuclear CuII complexes depending on the amount of ligand added. The resulting complexes were characterized by single crystal X-ray diffraction, elemental analysis, and cyclic voltammetry. [ABSTRACT FROM AUTHOR]

Reactions of copper(II) sulfate with 2,2′-bipyridine (bipy) and amino acids with nonpolar side chains (l-alanine (HAla), l-valine (HVal), or l-phenylalanine (HPhe)) were investigated under different solution-based and mechanochemical methods. Five new ternary coordination compounds were obtained by a solution-based synthesis and three of them additionally by the liquid-assisted mechanochemical method: {[Cu(μ-l-Ala)(H2O)(bipy)]2SO4·2H2O}n (1a·2H2O), {[Cu(μ-l-Ala)(H2O)(bipy)][Cu(l-Ala)(H2O)(bipy)]SO4·2.5H2O}n (1b·2.5H2O), {[Cu(μ-l-Val)(H2O)(bipy)][Cu(l-Val)(H2O)(bipy)]3(SO4)2·4H2O}n (2·4H2O), [Cu(l-Phe)(H2O)(bipy)][Cu(l-Phe)(SO4)(bipy)]∙8H2O (3·8H2O), and [Cu(l-Phe)(H2O)(bipy)][Cu(l-Phe)(SO4)(bipy)]∙9H2O (3·9H2O). The compounds were characterized by single-crystal and powder X-ray diffraction, infrared spectroscopy, and a thermal analysis. Structural studies revealed two structural types, monomeric in 3·8H2O and 3·9H2O, polymeric architectures in 1a·2H2O, and mixed structures (monomeric and polymeric) in 1b·2.5H2O and 2·4H2O. The copper(II) ion is either pentacoordinated or hexacoordinated, with an observed Jahn–Teller effect. The crystal structures are based on an intensive network of hydrogen bonds and π interactions. 1a·2H2O and 2·4H2O showed substantial in vitro antiproliferative activity toward human hepatocellular carcinoma (HepG2) and moderate activity toward human acute monocytic leukemia cell lines (THP-1). [ABSTRACT FROM AUTHOR]

A reaction between copper(II) nitrate and trans-1,4-cyclohexanedicarboxylic acid (H2chdc) carried out under hydrothermal conditions led to a new metal-organic coordination polymer [Cu2(Hchdc)2(chdc)]n. According to single-crystal XRD data, the compound is based on bi-nuclear paddlewheel-type carboxylate blocks that are joined with polymeric chains due to the (μ3-κ1:κ2) coordination of carboxylate groups. The chains are interconnected by chdc2− bridging ligands into layers containing free COOH groups of terminal Hchdc−. The neighboring layers adopt a RCOOH···OOCR hydrogen bond-assisted arrangement into a dense-packed structure. Magnetization measurements showed the presence of a strong antiferromagnetic exchange interaction (J/kB = −495 K) inside the bi-nuclear blocks. At the same time, no significant interaction was found between the {-Cu2(OOCR)4-} units in spite of their polymeric in-chain packing. Patterns of magnetic behavior of [Cu2(Hchdc)2(chdc)]n were thoroughly analyzed and explained from a structural point of view. [ABSTRACT FROM AUTHOR]

A family of silver(I) and copper(I) complexes containing carboxylate ligands were prepared from the corresponding carboxylic acids and Ag2O. The compounds were characterized by various spectroscopic methods and X-ray diffraction. In the solid state, the silver(I) salts are coordination polymers based on dinuclear silver species with bridging carboxylate ligands. The reaction of these silver salts with Ph3P gives four-coordinate, tetrahedral bis(phosphine) complexes. Analogous copper(I) bis(phosphine) compounds were prepared by the reduction of copper(II) carboxylates with Ph3P. Decomposition temperatures and thermal decomposition products were studied by TGA/DSC measurements. The metal compounds decomposed cleanly to their respective metals (silver or copper) at temperatures ranging from 206 to 338 °C. [ABSTRACT FROM AUTHOR]

The thioether-functionalized 2-azabutadiene (iPrS)2C=C(H)-N=CPh2 L ligates to CdI2 and HgI2 to form the chelate compounds [CdI2{(iPrS)2C=C(H)-N=CPh2] (1) and [HgI2(iPrS)2C=C(H)-N=CPh2] (2). Their crystal structures were solved via X-ray diffraction. Both crystallize in the non-centrosymmetric space groups: monoclinic P21 (1) and orthorhombic P212121 (2), respectively. The closed-shell d10 metal centers are four-coordinated (two iodides and S and N coordinating atoms from the ligand L) in both complexes. The geometrical indexes τ indicate that a highly distorted trigonal pyramidal is adopted for 1 and a seesaw geometry for 2. The comparative nature of metal–ligand bonds is discussed on the basis of metric parameters and of QT-AIM (quantum theory of atoms in molecules) calculations. L was also treated with CuI to obtain the dinuclear species [LCu(μ2-I2)CuL] (3), in which the two Cu(I) centers are linked by a short metal–metal bond. The geometric and electronic properties of 3 are compared with those of 1 and 2. [ABSTRACT FROM AUTHOR]

Reactions of N,N′-bis(3-methylpyridyl)oxalamide (L1), N,N'-bis(3-methylpyridyl)adipoamide (L2) and N,N'-bis(3-methylpyridyl)sebacoamide (L3) with tricarboxylic acids and Cu(II) salts afforded {[Cu(L1)(1,3,5-HBTC)]·H2O}n (1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid), 1, {[Cu1.5(L2)1.5(1,3,5-BTC)(H2O)2]·6.5H2O}n, 2, [Cu(L2)0.5(1,3,5-HBTB)]n (1,3,5-H3BTB = 1,3,5-tri(4-carboxyphenyl)benzene), 3, [Cu4(L3)(OH)2(1,3,5-BTC)2]n, 4, {[Cu3(L3)2(1,3,5-BTB)2]·2.5MeOH·2H2O}n, 5, and {[Cu3(L3)2(1,3,5-BTB)2 ]·DMF·2H2O}n, 6, which have been structurally characterized by using single crystal X-ray crystallography. Complexes 1–4 form a 2D layer with the {44.62}-sql topology, a 2D layer with the (4.62)2(42.62.82)-bex topology, a three-fold interpenetrated 3D net with the (412·63)-pcu topology and a 3D framework with the (410·632·83)(42·6)2(43·63) topology, respectively, whereas 5 and 6 are 3D frameworks with the (63)2(64·82)(68·85·102) topology. Complex 5 shows a better iodine adsorption factor of 290.0 mg g−1 at 60 °C for 360 min than the other ones, revealing that the flexibility of the spacer ligand governs the structural diversity and the adsorption capacity. [ABSTRACT FROM AUTHOR]

In the present work, novel polymeric copper(II) coordination compounds, namely [Cu2(cpida)(H2O)4][Cu(cpida)]·3H2O (1) (cpida3− = 2-(carboxyphenyl)iminodiacetate anion) and Na[Cu(cpida)] (3), were synthesized and characterized using infrared spectroscopy, thermogravimetric analysis, elemental analysis, and single-crystal X-ray diffraction. Compound 1 was obtained by slowly evaporating an aqueous solution of H3cpida, copper(II) sulfate, and NaOH at room temperature. The structural characterization revealed that 1 is an ionic entity formed by the [Cu(cpida)]− anion and the [Cu2(cpida)(H2O)4]+ cation, both of polymeric 1D structure. Compound 3 was prepared under similar conditions from copper perchlorate and crystallized via acetone diffusion. It is a coordination polymer formed by the [Cu(cpida)]− units, and the sodium cation is present in the structure, counterbalancing the anion charge. Depending on the crystallization conditions, it was possible to obtain other solvation forms of these structures. Starting from the conditions of compound 1, via the diffusion of ethanol, [Cu2(cpida)(H2O)4][Cu(cpida)]·H2O·1/2EtOH (2) was precipitated, while a hydrate form of compound 3 with the formula Na[Cu(cpida)]·2H2O (4) was obtained via methanol diffusion. [ABSTRACT FROM AUTHOR]

An aqueous Cu2+ and Zn2+ indicator is reported based on copolymerizing aminopyridine ligands and the environment-sensitive dansyl fluorophore into the responsive polymer poly(N-isopropylacrylamide) (PNIPAm). The metal ion binding creates charge and solvation that triggers PNIPAm's thermal phase transition from hydrophobic globule to hydrophilic open coil. As a basis for sensing the metal-binding, the dansyl fluorescence emission spectra provide a signal at ca. 530 nm and a signal at 500 nm for the hydrophobic and hydrophilic environment, respectively, that are ratiometrically interpreted. The synthesis of the title pyridylethyl-pyridylmethyl-amine ligand (acronym PEPMA) with a 3-carbon linker to the copolymerizable group, aminopropylacrylamide (PEPMA-C3-acrylamide), is reported, along with a nonpolymerizable model ligand derivative. The response of the polymer is validated by increasing temperature from 25 °C to 49 °C, which causes a shift in maximum emission wavelength from 536 nm to 505 nm, along with an increase in the ratio of emission intensity of 505 nm/536 nm from 0.77 to 1.22 (λex = 330 nm) as the polymer releases water. The addition of divalent Cu or Zn to the indicator resulted in a dansyl emission shift of 10 nm to a longer wavelength, accompanied by fluorescence quenching in the case of Cu2+. The addition of EDTA to the Cu2+-loaded indicator reversed the fluorescence shift at 25 °C to 35 °C. The affinities of Cu2+ and Zn2+ for the PEPMA derivatives are log Kf = 11.85 and log Kf = 5.67, respectively, as determined by potentiometric titration. The single-crystal X-ray structure of the Cu2+-PEPMA derivative is five-coordinate, of-geometry intermediate between square-pyramidal and trigonal-bipyramidal, and is comparable to that of Cu2+ complexes with similar formation constants. [ABSTRACT FROM AUTHOR]

A combination of 4-styrylpyridine (spy) and 1-adamantanecarboxylic acid (Hadc) was employed in the assembly reactions with Zn(II) and Cu(II) nitrates. The photoreactivity of the products was compared and discussed on the basis of the structure–function relationship. Zinc(II) complex 1 is a trinuclear species of type [Zn3(spy)2(adc)6] in which three zinc(II) atoms are linearly arranged, with two adjacent zinc(II) atoms linked by three bridging carboxylates. Two spy ligands occupy both terminal positions, yielding the overall structure of a six-bladed windmill. Copper(II) complex 2, [Cu(spy)2(adc)2][Cu2(spy)2(adc)4]·2DMF, is an inorganic cocrystal comprising a mononuclear complex with a trans square planar geometry and a dinuclear complex with a paddle-wheel structure. In the photoreaction experiments characterized by 1H NMR spectroscopy, the zinc(II) complex was found to be photoinert, while the copper(II) complex was photoreactive to form a cyclobutene ring via the [2+2] photodimerization between two spy ligands, resulting in the preparation of a one-dimensional chain as a coordination polymer. The separations of the C=C bond pair obtained from the crystal structures for both products also support their photoreactivity. For example, the spy ligands from two adjacent monocopper(II) complexes are aligned in a head-to-tail manner with the separation of 3.899 Å between the C=C bond pair, satisfying the so-called Schmidt criteria (<4.2 Å). However, no other products satisfy this condition. [ABSTRACT FROM AUTHOR]

Four new NiII, CoII, ZnII, and CuII complexes with the promising anti-tuberculosis drug (E/Z)-N′-((5-Hydroxy-3,4-bis(hydroxymethyl)-6-methylpyridin-2-yl)methylene)-isonicotino-hydrazide (LH) were synthesized and characterized by structural methods: single-crystal X-ray diffraction, vibrational spectroscopy, and mass spectrometry. The NiII, CoII, and ZnII metal ions form only amorphous phases with various morphologies according to mass spectrometry and IR spectroscopy. The CuII forms a crystalline 1D coordination polymer with the relative formula { [ Cu L Cl ] · 0.5 H 2 O } ∞ 1 . Even though the LH ligand in the crystalline state includes a mixture of E-/Z-isomers, only the tautomeric iminol E-/Z-form is coordinated by CuII in the crystal. The copper(II) complex crystallizes in the monoclinic P21/n space group with the corresponding cell parameters a = 16.3539(11) Å, b = 12.2647(6) Å, and c = 17.4916(10) Å; α = 90°, β = 108.431(7)°, and γ = 90°. DFT calculations showed that the Z-isomer of the LH ligand in solution has the lowest formation energy due to intramolecular hydrogen bonds. According to the quantum chemical calculations, the coordination environment of the CuII atom during the transfer of the molecule into the solution remains the same as in the crystal, except for the polymeric bond, namely, distorted trigonal bipyramidal. Some of the complexes investigated can be used as effective sensors in biosystems. [ABSTRACT FROM AUTHOR]

The influence of arene/perfluoroarene ratio on the structure and crystal packing of carboxylate and nitrate-carboxylate complexes of Cd, Cd-Tb and Cu was studied, using the following compounds: pentafluorobenzoate (pfb) and 4-allyl-2,3,5,6-tetrabenzoate (Afb) anions and 1,10-phenanthroline (phen) composition [Cd(pfb)2(phen)]n (1), [Cd(NO3)(pfb)(phen)]n (2), [Tb2Cd2(pfb)10(phen)2]. 3MeCN]n (3), [Tb2Cd2(NO3)2(pfb)8(phen)2.1.5MeCN]n (4), [Cu2(Afb)4(phen)2] (5), [Cu2(NO3)2(Afb)2(phen)2] (6). It is shown that the main contribution to the stabilization of the crystal packing of coordination polymers 1–4 and molecular binuclear complexes 5 and 6 can be attributed to non-covalent π···π, C-H···F, and C-F···π interactions. It was found that the partial exchange of pfb or Afb anions on compact NO3− anions leads to a decrease in steric hindrance, a more efficient overlap of aromatic fragments, and a significant change in the geometry of complexes. Synthesized compounds were characterized by X-ray diffraction analysis, IR spectroscopy, and CHN analysis. The thermal stability of complexes 1 and 2 was studied. Non-covalent interactions were analyzed using the Hirshfeld surface method. [ABSTRACT FROM AUTHOR]

The antimicrobial activity of the novel coordination polymers obtained by co-crystallizing the amino acids arginine or histidine, as both enantiopure L and racemic DL forms, with the salts Cu(NO3)2 and AgNO3 has been investigated to explore the effect of chirality in the cases of enantiopure and racemic forms. The compounds [Cu·AA·(NO3)2]CPs and [Ag·AA·NO3]CPs (AA = L-Arg, DL-Arg, L-His, DL-His) were prepared by mechanochemical, slurry, and solution methods and characterized by X-ray single-crystal and powder diffraction in the cases of the copper coordination polymers, and by powder diffraction and by solid-state NMR spectroscopy in the cases of the silver compounds. The two pairs of coordination polymers, [Cu·L-Arg·(NO3)2·H2O]CP and [Cu·DL-Arg·(NO3)2·H2O]CP, and [Cu·L-Hys·(NO3)2·H2O]CP and [Cu·DL-His·(NO3)2·H2O]CP, have been shown to be isostructural in spite of the different chirality of the amino acid ligands. A similar structural analogy could be established for the silver complexes on the basis of SSNMR. The activity against the bacterial pathogens Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus was assessed by carrying out disk diffusion assays on lysogeny agar media showing that, while there is no significant effect arising from the use of enantiopure or chiral amino acids, the coordination polymers exert an appreciable antimicrobial activity comparable, when not superior, to that of the metal salts alone. [ABSTRACT FROM AUTHOR]

Employing the new nitronyl nitroxide biradical ligand biNIT-3Py-5-Ph (2-(5-phenyl-3-pyridyl)-bis(4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide)), a 16-spin Cu-radical complex, [Cu8(biNIT-3Py-5-Ph)4(hfac)16] 1, and three 2p-3d-4f chain complexes, {[Ln(hfac)3][Cu(hfac)2]2(biNIT-3Py-5-Ph)2}n (LnⅢ= Gd 2, Tb 3, Dy 4; hfac = hexafluoroacetylacetonate), have been prepared and characterized. X-ray crystallographic analysis revealed in all derivatives a common cyclic [Cu-biNIT]2 secondary building unit in which two bi-NIT-3Py-5-Ph biradical ligands and two CuII ions are associated via the pyridine N atoms and NO units. For complex 1, two such units assemble with four additional CuII ions to form a discrete complex involving 16 S = 1/2 spin centers. For complexes 2–4, the [Cu-biNIT]2 units are linked by LnIII ions via NO groups in a 1D coordination polymer. Magnetic studies show that the coordination of the aminoxyl groups with Cu or Ln ions results in behaviors combining ferromagnetic and antiferromagnetic interactions. No slow magnetic relaxation behavior was observed for Tb and Dy derivatives. [ABSTRACT FROM AUTHOR]

Co-crystallization of kojic acid (HKA) with silver(I), copper(II), zinc(II), or gallium(III) salts yielded three 1D coordination polymers and one 0D complex in which kojic acid was present as a neutral or anionic terminal or bridging ligand. All reactions were conducted mechanochemically via ball milling and manual grinding, or via slurry. All solids were fully characterized via single-crystal and/or powder X-ray diffraction. As kojic acid is a mild antimicrobial compound that is widely used in cosmetics, and the metal cations possess antibacterial properties, their combinations were tested for potential antibacterial applications. The minimal inhibition concentrations (MICs) and minimal biocidal concentrations (MBCs) for all compounds were measured against standard strains of the bacteria P. aeruginosa, S. aureus, and E. coli. All compounds exerted appreciable antimicrobial activity in the order of silver, zinc, copper, and gallium complexes. [ABSTRACT FROM AUTHOR]

We report the synthesis and characterization of a 3D Cu(II) coordination polymer, [Cu3(L1)2(H2O)8]·8H2O (1), with the use of a glycine-based tripodal pseudopeptidic ligand (H3L1 = N,N0,N0 0-tris(carboxymethyl)-1,3,5-benzenetricarboxamide or trimesoyl-tris-glycine). This compound presents the first example of a 12-fold interpenetrated ThSi2 (ths) net. We attempt to justify the unique topology of 1 through a systematic comparison of the synthetic parameters in all reported structures with H3L1 and similar tripodal pseudopeptidic ligands. We additionally explore the catalytic potential of 1 in the A3 coupling reaction for the synthesis of propargylamines. The compound acts as a very good heterogeneous catalyst with yields up to 99% and loadings as low as 3 mol %. [ABSTRACT FROM AUTHOR]

We report on the use of different reaction conditions, e.g., temperature, time, and/or concentration of reactants, to gain control over the particle formation of a bioinspired coordination polymer based on copper(II) and adenine, allowing homogeneous particle production from micro- to submicro-, and up to nano-size. Additionally, studies on this reaction carried out in the presence of different surfactants gives rise to the control of the particle size due to the modulation of the electrostatic interactions. Stability of the water suspensions obtained within the time and pH has been evaluated. We have also studied that there is no significant effect of the size reduction in the magnetic properties of the Cu(II)-adenine coordination polymer. [ABSTRACT FROM AUTHOR]

Three new copper coordination compounds derived from 2,2-bis(hydroxymethyl)propionic acid (dmpa) and hexamethylenetetramine (hmta) were obtained and their crystal structures were determined. The stoichiometry of the reagents applied in the syntheses reflects the metal to ligand molar ratio in the formed solid products. Due to the multiple coordination modes of the used ligands, wide structural diversity was achieved among synthesized compounds, i.e., mononuclear [Cu(dmp)2(hmta)2(H2O)] (1), dinuclear [Cu2(dmp)4(hmta)2] (2), and 1D coordination polymer [Cu2(dmp)4(hmta)]n (3). Their supramolecular structures are governed by O—H•••O and O—H•••N hydrogen bonds. The compounds were characterized in terms of absorption (UV-Vis and IR) and thermal properties. The relationships between structural features and properties were discussed in detail. Owing to discrepancies in the coordination mode of a dmp ligand, bidentate chelating in 1, and bidentate bridging in 2 and 3, there is a noticeable change in the position of the bands corresponding to the stretching vibrations of the carboxylate group in the IR spectra. The differences in the structures of the compounds are also reflected in the nature and position of the UV-Vis absorption maxima, which are located at lower wavelengths for 1. [ABSTRACT FROM AUTHOR]

Two novel copper(II) complexes of formulas {[Cu(4-Hmpz)4][Cu(4-Hmpz)2(µ3-ox-κ2O1,O2:κO2′:κO1′)(ClO4)2]}n (1) and {[Cu(3,4,5-Htmpz)4]2[Cu(3,4,5-Htmpz)2(µ3-ox-κ2O1,O2:κO2′:κO1′)(H2O)(ClO4)]2[Cu2(3,4,5-Htmpz)4(µ-ox-κ2O1,O2:κ2O2′,O1′)]}(ClO4)4·6H2O (2) have been obtained by using 4-methyl-1H-pyrazole (4-Hmpz) and 3,4,5-trimethyl-1H-pyrazole (3,4,5-Htmpz) as terminal ligands and oxalate (ox) as the polyatomic inverse coordination center. The crystal structure of 1 consists of perchlorate counteranions and cationic copper(II) chains with alternating bis(pyrazole)(µ3-κ2O1,O2:κO2′:κO1′-oxalato)copper(II) and tetrakis(pyrazole)copper(II) fragments. The crystal structure of 2 is made up of perchlorate counteranions and cationic centrosymmetric hexanuclear complexes where an inner tetrakis(pyrazole)(µ-κ2O1,O2:κ2O2′,O1′-oxalato)dicopper(II) entity and two outer mononuclear tetrakis(pyrazole)copper(II) units are linked through two mononuclear aquabis(pyrazole)(µ3-κ2O1,O2:κO2′:κO1′-oxalato)copper(II) units. The magnetic properties of 1 and 2 were investigated in the temperature range 2.0–300 K. Very weak intrachain antiferromagnetic interactions between the copper(II) ions through the µ3-ox-κ2O1,O2:κO2′:κO1′ center occur in 1 [J = −0.42(1) cm−1, the spin Hamiltonian being defined as H = −J∑S1,i · S2,i+1], whereas very weak intramolecular ferromagnetic [J = +0.28(2) cm−1] and strong antiferromagnetic [J' = −348(2) cm−1] couplings coexist in 2 which are mediated by the µ3-ox-κ2O1,O2:κO2′:κO1′ and µ-ox-κ2O1,O2:κ2O2′,O1′ centers, respectively. The variation in the nature and magnitude of the magnetic coupling for this pair of oxalato-centered inverse copper(II) complexes is discussed in the light of their different structural features, and a comparison with related oxalato-centered inverse copper(II)-pyrazole systems from the literature is carried out. [ABSTRACT FROM AUTHOR]

The simultaneous use of 2-pyridyl oximes (pyridine-2 amidoxime, H2pyaox; 2-methyl pyridyl ketoxime, Hmpko) and 1,3,5-benzenetricarboxylic acid (H3btc) provided access to five new compounds, namely [Zn(H2btc)2(H2pyaox)2]•2H2O (1•2H2O), [Zn(Hbtc)(H2pyaox)2]n (2), [Cu(Hbtc)(H2pyaox)]n (3), [Cu(Hbtc)(HmpKo)]n (4) and [Cu2(Hbtc)2(Hmpko)2(H2O)2]•4H2O (5•4H2O). Among them, 3 is the first example of a metal-organic framework (MOF) containing H2pyaox. Its framework can be described as a 3-c uninodal net of hcb topology with the layers being parallel to the (1,0,1) plane. Furthermore, 3 is the third reported MOF based on a 2-pyridyl oxime in general. 2 and 4 are new members of a small family of coordination polymers containing an oximic ligand. 1–5 form 3D networks through strong intermolecular interactions. Dc magnetic susceptibility studies were carried out in a crystalline sample of 3 and revealed the presence of weak exchange interactions between the metal centres; the experimental data were fitted to a theoretical model with the fitting parameters being J = −0.16(1) cm−1 and g = 2.085(1). The isotropic g value was also confirmed by electronic paramagnetic resonance (EPR) spectroscopy. Reactivity studies were performed for 3 in the presence of metal ions; the reaction progress was studied and discussed for Fe(NO3)3 by the use of several characterization techniques, including single crystal X-ray crystallography and IR spectroscopy. [ABSTRACT FROM AUTHOR]

Several important synthesis pathways for metal-organic frameworks (MOFs) were applied to determine how the synthesis methods and conditions affect the structure and adsorption capacity of the resulting samples. In the present work, three different synthesis routes were used to obtain copper trimesinate coordination polymer: Slow evaporation (A), solvothermal synthesis using a polyethylene glycol (PEG-1500) modulator (B), and green synthesis in water (C). This MOF was characterized by elemental analysis, infrared spectrometry, X-ray diffraction, scanning electron microscopy, thermogravimetry and volumetric nitrogen adsorption/desorption. The samples have permanent porosity and a microporous structure with a large surface area corresponding to the adsorption type I. The obtained MOF was tested as a sorbent to remove organic dyes methylene blue (МВ), Congo red (CR) and methyl violet (MV) as examples. Dye adsorption followed pseudo-first-order kinetics. The equilibrium data were fitted to the Langmuir and Freundlich isotherm models, and the isotherm constants were determined. Thermodynamic parameters, such as changes in the free energy of adsorption (∆G0), enthalpy (∆H0), and entropy (∆S0), were calculated. Thermolysis of copper trimesinate leads to the formation of carbon materials Cu@C with a high purity. [ABSTRACT FROM AUTHOR]

Three 1,4,7,10-tetraazacyclododecane-based ligands disubstituted in 1,4-positions with phosphonic acid, phosphonate monoethyl-ester, and H-phosphinic acid pendant arms, 1,4-H4do2p, 1,4-H2do2pOEt, and 1,4-H2Bn2do2pH, were synthesized and their coordination to selected metal ions, Mg(II), Ca(II), Mn(II), Zn(II), Cu(II), Eu(III), Gd(III), and Tb(III), was investigated. The solid-state structure of the phosphonate ligand, 1,4-H4do2p, was determined by single-crystal X-ray diffraction. Protonation constants of the ligands and stability constants of their complexes were obtained by potentiometry, and their values are comparable to those of previously studied analogous 1,7-disubstitued cyclen derivatives. The Gd(III) complex of 1,4-H4do2p is ~1 order of magnitude more stable than the Gd(III) complex of the 1,7-analogue, probably due to the disubstituted ethylenediamine-like structural motif in 1,4-H4do2p enabling more efficient wrapping of the metal ion. Stability of Gd(III)–1,4-H2do2pOEt and Gd(III)–H2Bn2do2pH complexes is low and the constants cannot be determined due to precipitation of the metal hydroxide. Protonations of the Cu(II), Zn(II), and Gd(III) complexes probably takes place on the coordinated phosphonate groups. Complexes of Mn(II) and alkali-earth metal ions are significantly less stable and are not formed in acidic solutions. Potential presence of water molecule(s) in the coordination spheres of the Mn(II) and Ln(III) complexes was studied by variable-temperature NMR experiments. The Mn(II) complexes of the ligands are not hydrated. The Gd(III)–1,4-H4do2p complex undergoes hydration equilibrium between mono- and bis-hydrated species. Presence of two-species equilibrium was confirmed by UV-Vis spectroscopy of the Eu(III)–1,4-H4do2p complex and hydration states were also determined by luminescence measurements of the Eu(III)/Tb(III)–1,4-H4do2p complexes. [ABSTRACT FROM AUTHOR]

Several binary metal diphosphinate compounds (ML) have been reported for diphosphinate bonded by a single methylene fragment. In case of longer bridges, binary products are difficult to isolate in crystalline form. Here, using a solvent assisted mechano-chemistry synthesis, we report two new ML crystalline phases, one hydrated and one anhydrous. The hydrated phase is a 2D coordination polymer with an open framework structure. Its network displays a new topology for coordination polymers and metal organic frameworks. The thermal behavior of the two phases has been studied. Finally, the importance of the bridge length is discussed in view of known metal diphosphinate compounds. [ABSTRACT FROM AUTHOR]