Structure and properties of complex transition-metal (II) salts of ethylene-methacrylic acid copolymer with 1,3-bis (aminomethyl) cyclohexane

Thermal properties by differential scanning calorimetry, stiffness, and melt flow rate (MFR) were measured for the complex transition-metal (Zn(II), Cu(II), Mn(II), and Co(II)) salts of ethylene-methacrylic acid copolymer (EMAA) with 1,3-bis(aminomethyl)-cyclohexane (BAC). It was found that the strength of both ionic interactions of metal cations with carboxyl groups and coordination bonds of amino groups to metals differ among metal species. In particular, the complex Mn salts are weaker than the complex salts of the other transition metals, which corresponds with Irving-Williams series of stability constants of transition metal-ion complexes. Stiffness depends predominantly on the degree of crystallinity of ionic crystallites in ionic clusters, which depends on the ionic species.     

Dynamic and steady-shear melt rheology of and ethylene-methacrylic acid copolymer and its salts

Studies have been made on the dynamic and steady-shear melt rheology of an ethylene–methacrylic acid copolymer and two of its salts obtained by partial neutralization with sodium and with calcium bases. Measurements were made with a Weissenberg rheogoniometer over a broad range of shear rates and frequency in the temperature interval mainly from 100 to 160°C. The temperature coefficients of dynamic and steady shear viscosity are evaluated at both constant shear rate and constant stress. Likewise, complex dynamic viscosities and apparent high steady-flow viscosities and intercompared at equivalent frequencies and shear rates. The un-ionized acid copolymer shows good correlation between the frequency dependence of the complex viscosity and the shear rate dependence of the apparent viscosity. This is not true for either the sodium salt or the calcium salt. These results are consistent with the two-phase structural model for these materials, i.e., a matrix of hydrocarbon in which are embedded ionic domains.     

Further annealing studies of the calcium salt of an ethylene-methacrylic acid copolymer

Annealing studies of the calcium salt of an ethylene-methacrylic acid copolymer are reported. Fourier-transform infrared spectroscopy and differential scanning calorimetry were applied to the investigation of the effect of polyethylene crystallization on ionic structure as a function of annealing temperature and time. The spectroscopic changes observed in the spectra of the calcium salt annealed at 80°C differ from those seen in the spectra of the calcium salt annealed at room temperature. These changes are interpreted in terms of the multiplet-cluster model and the effect of the polyethylene-type crystallinity on the ionic microstructure.     

Characterization and biological properties of a copper(II) complex with pyruvic acid thiosemicarbazone

Summary A copper(II) complex with pyruvic acid thiosemicarbazone (PTSC) of composition Cu(PTSC) (PTSC-H)Cl was characterized by IR, UV/Vis, and EPR spectroscopy. The antifungo, herbicide, cytotoxic and antitumor activities of the complex andPTSC are reported.

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Charakterisierung und biologische Eigenschaften eines Kupfer(II)-Komplexes mit Brenztraubensäurethiosemicarbazon

Zusammenfassung Ein Kupfer(II)-Komplex mit Brenztraubensäurethiosemicarbazon (PTSC) der Zusammensetzung Cu(PTSC)(PTSC-H)Cl wurde mittels IR-, UV/Vis- und EPR-Spektroskopie charakterisiert. Es wird über die antifungalen, herbiziden, cytotoxischen und antitumoralen Aktivitäten des Komplexes und vonPTSC berichtet.

     

Synthesis and properties of new tetrachlorocobaltate (II) and tetrachloromanganate (II) anion salts with dicationic counterions

New tetrachlorocobaltate (II) and tetrachloromanganate (II) ionic compounds containing various counterdications were synthesized and characterized. These salts are soluble in polar solvents such as methanol and water. Physical properties such as thermal stability, melting point, and magnetic susceptibility of these salts depend on the cation or anion structure. The thermal stability of the phosphinium or imidazolium based salts is higher than that of the pyridinium or triethylaminonium analogues. The melting point of these compounds is following the order of triphenylphosphinium > pyridinium > imidazolium dications, and symmetrical dicationic salts > unsymmetrical ones. The magnetic susceptibility (χ_MT values) of tetrachloromanganate (II) anions-based salts is higher than that of tetrachlorocobaltate (II) anions-based salts. These dicationic salts exhibit weak antiferromagnetic interactions and have higher magnetic susceptibility than that of the previously reported tetrachloromanganate (II) and tetrachlorocobaltate(II) salts with monocationic counterion.     

Cavitand zn(II)-porphyrin capsules with high affinities for pyridines and N-methylimidazole

Covalent cavitand Zn(II)-porphyrins 17-20 were prepared via multistep syntheses. These host molecules show moderate to excellent binding affinities to N-methylimidazole and pyridine guests. The complexing behavior strongly depends on the spacer's length, number, and rigidity, in addition to the guest size. Cavitand capping and strapping of porphyrins strongly influence the complex formation and result in a 10-700-fold enhancement of the binding strength compared to tetraphenyl Zn(II)-porphyrin.     

Structure and thermal reactivity of Zn(II) salts of isocinchomeronic acid (2,5-pyridinedicarboxylic acid)

The synthesis, an improved refined crystal and molecular structure re-determination, and the thermal decomposition behavior of two Zn(II) derivatives of isocinchomeronic acid (2,5-pyridinedicarboxylic acid or H₂2,5-pydc) are presented. [Zn(2,5-pydc)(H₂O)₃Zn(2,5-pydc)(H₂O)₂]₂ (1) crystallizes in the triclinic P-1 space group with a = 7.106(2), b = 11.450(2), c = 11.869(1) Å, α = 107.29(1), β = 104.08(1), γ = 90.32(2)°, and Z = 2. [Zn(2,5-pydc)(H₂O)₂] · H₂O (2) is orthorhombic (P2₁2₁2₁ space group), with a = 7.342(1), b = 9.430(1), c = 13.834(2) Å, and Z = 4. The structures were refined to agreement R ₁-factors of 0.0315 (1) and 0.0336 (2). Complex (1) is arranged as molecular Zn₄(2,5-pydc)₄(H₂O)₁₀ tetramers, the cages of which define channels that remain unblocked by anions. Compound (2) is polymeric with Zn(2,5-pydc)(H₂O)₂ and Zn(2,5-pydc)(H₂O)₃ units linked through bridging ligands. Both compounds were synthesized under mild conditions in aqueous media, without need to resort to hydrothermal media. Changing the pH from 4.51 to 5.75 suffices to direct the chemical processes toward the orthorhombic compound rather than to the triclinic one.     

Enantiomeric pairs of copper(II) polypyridyl-alanine complex salts: anticancer studies

The anticancer properties of two previously characterized pairs of optically pure chiral complex salts [Cu(phen)(ala)(H₂O)]X·xH₂O (phen?=?1.10-phenanthroline; X?=?NO₃^?; ala: l-alanine (l-ala) 1 and d-alanine (d-ala) 2; and (X?=?Cl^?; ala: l-ala, 3 and d-ala, 4; x?=?number of lattice water molecules) are reported herein, together with the crystal structure of the d-enantiomer 4. Unlike cisplatin which is ineffective against MCF-7 cancer cells with the absence of caspase-3 protein expression, these two pairs of complex salts were effective against this cell line and they were able to induce an increase in intracellular ROS, loss in mitochondrial membrane potential, cell cycle arrest mainly at SubG1 phase , caspase-9 activation, and caspase-3/caspase-7-independent apoptosis. Screening of 1 on the NCI-60 panel of human cancer cell lines showed that it was effective against most of the cell lines. MTT-NCI modified assay screening was also done on other cancer cell lines, viz. A549, CNE1, and HepG2, and two normal cell lines, viz. MCF-10A and CHANG. The effects of chirality of these Cu(II) compounds, especially the greater selectivity of d-enantiomers over the l-counterparts, on their anticancer properties are also reported herein.     

Crystal structure and magnetic properties of a new heterometallic complex of Pd(II)-Cu(II) with 1-aminoethylidene-1,1-diphosphonic acid

A heterometallic complex of Pd(II)-Cu(II) with 1-aminoethylidene-1,1-diphosphonic (AEDP) acid (C₄H₂₂CuN₂O₁₆P₄Pd) _n (I) is synthesized. Single crystals of compound I are obtained; its crystal structure is determined by X-ray crystallography. The crystals are orthorhombic, space group Pbcn, a = 18.366(3) Å, b = 9.7661(17) Å, c = 20.198(4) Å, V = 3622.8(11) ų, Z = 8, d _x = 2.376 g/cm³. The compound crystallizes as a coordination polymer; the square environment of Pd(II) is formed by nitrogen atoms of amino groups and oxygen atoms of phosphonic groups, while at two non-equivalent copper atoms the octahedral environment is formed by oxygen atoms of phosphonic groups and water molecules. The crystal structure of compound I is characterized by the formation of a branched network of hydrogen bonds. Based on the analysis of the temperature dependence of the magnetic susceptibility it is found that for the heterometallic complex of Pd(II)-Cu(II) with AEDP antiferromagnetic interactions between the paramagnetic centers are dominant.     

Supramolecular architecture and magnetic properties of copper(II) and nickel(II) porphyrinogen-TCNQ electron-transfer salts

The compounds [Cu(Tz)-(MeOH)2](TCNQ)2 (1), [Ni(Tz)-(MeOH)2](TCNQ)2 (2), [Cu(Tz)2]-(TCNQ)7 (3) and [Ni(Tz)2](TCNQ)7 (4) (Tz = 2,7,12,17-tetramethyl-1,6,11,16-tetraazaporphyrinogen) were obtained by metathesis reaction of [M(Tz)](ClO4)2 with LiTCNQ and Et3NH(TCNQ)2, respectively. They were characterized by a combination of spectroscopic and physical methods. Compound 1 crystallizes in the monoclinic space group P2(1)/n with a = 8.310(2), b = 25.180(4), c = 20.727(4) A, beta = 93.58(2) degrees; Z = 4. Compound 3 crystallizes in the triclinic space group P1 with a = 11.244(1), b = 16.700(1), c = 17.321(1) A, a = 113.47(1), beta = 108.52(1), gamma = 96.12(1) degrees; Z = 2. The asymmetric unit of the compound 1 is formed by cationic [Cu(Tz)(MeOH)2]2+ and by two crystallographically non equivalent TCNQ.- anions; these anions form dimeric units by overlap of the pi clouds. The dimers form hydrogen bonds with the metal-lomacrocyclic cation through the methanol ligands. According to this structure the compound is paramagnetic and behaves as an insulator in the temperature range studied. The paramagnetism arises only from the metal-complex moieties. Compound 3 shows an unprecedented structure due to the steric requirements of the macrocycle that favors the stacking of the TCNQ groups. The structure consists of infinite stacks of TCNQ units separated by the metal-macrocyclic units; there are seven TCNQ molecules per formula unit, one of which is formally mono-anionic, while the other six bear one half of an electron per molecule. The copper is six-coordinate in a very distorted octahedral environment. The Tz ligand is located in the equatorial plane and the apical nitrogens of the nitrile groups of two TCNQ molecules complete the coordination around the copper. The compound is a semiconductor and its magnetic behavior can be explained by the sum of the Curie contribution of the metal complex and the contribution arising from the magnetic-exchange interactions of the spins located on the TCNQ units. The latter is found to be typical of one-dimensional antiferromagnetic distorted chains of S = 1/2 spins and can be fitted according to a one-dimensional Heisenberg antiferromagnetic model.     

An ytterbium(II) complex with dimethyl ester of oxydiacetic acid

An Yb(II) complex with dimethyl ester of oxydiacetic acid, [Yb(CH(3)OOCCH(2)OCH(2)COOCH(3))3](ClO4)2, has been obtained by electrochemical reduction and its crystal structure has been determined. The complex cations have the D3 (32) crystallographic symmetry. The compound shows a very broad absorption band, starting from 500 nm towards the UV region, and traces of luminescence with a maximum at 545 nm. The performed density functional theory (DFT) calculations have shown that the absorption band results from mixed f-d and charge transfer transitions, and the empty antibonding pi* orbitals of the ester groups quench the luminescence.     

Thermal behaviour of thallium(I) fatty acid salts,II

The electrical conductivity (EC) changes of thallium(I) salts of fatty acids, which possess liquid crystalline phases, were investigated as a function of temperature. It was found that sharp EC jumps are associated with the phase transitions. The EC of the liquid crystalline phases depended not only on the temperature, the molecular weight and the geometry of the measuring cell, but also very sensitively on the heat treatment conditions which affect the relative magnitude of the EC in the mesophases.Study of these dependences revealed a memory effect. An explanation is given for this phenomenon.

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Zusammenfassung Die Änderungen der elektrischen Leitfähigkeit (EC) von Fettsäure-Thalium(I)-Salzen mit flüssig-kristallinen Phasen wurden als Funktion der Temperatur untersucht. Es wurde festgestellt, daß den Phasenübergängen scharfe EC-Sprünge entsprechen. Die EC der flüssig-kristallinen Phase hängt nicht nur von der Temperatur, dem Molekulargewicht und der Geometrie der Meßzelle ab, sondern auch — in sehr empfindlicher Weise — Phasen bestimmen.Die Untersuchung dieser Zusammenhänge führte zur Beobachtung eines »Memorieeffektes« Eine Erklärung dieser Erscheinung wird gegeben.

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Résumé On a étudié les variations de la conductibilité électrique (EC) des sels de thallium(I) des acides gras possédant des phases cristallines liquides, en fonction de la température. On a établi que les variations brusques d'EC correspondent aux transitions de phases. L'EC des phases cristallines liquides dépend non seulement de la température, de la masse molaire et de la géométrie de la cellule de mesure, mais aussi, et d'une manière très sensible, des conditions du traitement thermique qui affectent l'amplitude relative de l'EC dans les mésophases.Un «effet de mémoire» a été observé lors de l'étude de ces phénomènes, dont on donne une explication.

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Synthesis and structure of copper(II) complex with comenic acid

Russian Journal of General Chemistry -