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EN
Photoacoustic spectra of the d-d transitions for three different series of copper(II) complexes of spermidines Spn (Spn323, Spn333, Spn343), Spm (Spm323, Spm333, Spm343) and Spc (Spc323, Spc333) have been investigated. Replacements of distant atoms, the presence or absence of water molecule in the structure, the kind of ligands surrounding the metal(II) ions have a strong influence on the crystal field splitting and the intensities of the non-radiative transitions. Non-radiative processes are involved in important mechanisms of the dynamic interactions between the electrons and the lattice. Studies of the intensities of the non-radiative transitions provide a very important data for the thermodynamic states of these systems. Photoacoustic absorption band of the d-d transitions could be decomposed into three lines (due to the crystal field splitting) with different intensities, positions and linewidths. The integrated intensities may yield information about the number of non-radiative processes, while the linewidths about the mechanisms of the relaxation processes.
EN
[M+CuCl+H]2+ ions were generated using electrospray ionization (ESI); where M is a molecule of 3,5-bis(2,2’-bipyridin-4-ylethynyl)benzoic acid or its methyl ester (1 and 2, respectively). The ions were subjected to CID-MS/MS analysis. It was found that their gas phase decomposition lead to the formation of rare di-cations [M]2+, namely [1]2+ and [2]2+ ions. The formation of [1]2+ ion from [3+H+CuCl]2+ ion in the second fragmentation, where 3 is ethyl ester of 3,5-bis(2,2-bipyridin-4-ylethynyl)benzoic acid, was also observed since in the first fragmentation step the loss of ethylene molecule from [3+H+CuCl]2+ ion took place. To the best of our knowledge, it is the first time that [M]2+ ions formation from respective metal complexes has been reported. It is also unusual that formation of [M]2+ ions is not accompanied by formation of [M]+∙ ions. Furthermore, as expected, theoretical calculation and electron ionization mass spectra show that 1 and 2 are not especially prone to form [M]2+ ions. Thus formation of [M]2+ ions under CID conditions is very surprising.
EN
This brief review discusses the coordination behaviour of π-coordinated copper(I) in the structures of [Cu2(μ-dapp)(NH2SO3)4]·2H2O (1), [C4H12N2][Cu2(μ-dapp)(NH2SO3)6]·2H2O (2), [Cu2(μ-dapp)(H2O)6] (SiF6)2·2H2O (3), [Cu2(μ-dapp)(NO3)4(H2O)2]·2H2O (4), [Cu(μ-ahmta)(NO3)(H2O)](NO3)·H2O (5), and [Cu(μ-ahmta)(H2O)2](BF4)2·H2O (6) complexes (dapp = N,N′-diallylpiperazinium(2+), ahmta = N-allylhexamethylenetetraminium), obtained as single crystals by means of an alternating current electrochemical technique. The above π-complexes are formed respectively by CuSO3NH2, Cu2SiF6, CuNO3, and CuBF4 salts, unknown in a free state.
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Content available remote Synthesis and ESR study of (TbxY1 - x)2Cu2O5 solid solutions
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EN
Polycrystalline samples of (TbxY1 - x)2Cu2O5, where x = 1.0, 0.75, 0.50, 0.38, 0.25, 0.125 and 0, were synthesized by the solid-state reaction technique. XRD measurements showed that the obtained samples are single-phase and belong to the orthorhombic space group Pna21. The observed linear change of the lattice parameters and unit cell volume with terbium concentration is in agreement with Vegard's law. A thermogravimetric study of the decomposition process of the obtained samples revealed small sampledependent mass losses in the temperature range 1030-1050 °C, and a larger, intrinsic mass loss in the range 1100-1150 °C. The former are probably due to the 4 CuO › 2 Cu2O + O2 transformation, while the latter is related to the reaction 2Y2Cu2O5 › 4YCuO2 + O2. The peak temperature of the main decomposition stage varies linearly with terbium concentration, which could be explained by an increasing distortion of coordination polyhedra around the copper ion, caused by the substitution of the larger Tb3+ cation. The ESR spectra of (TbxY1 - x)2Cu2O5 solid solutions showed a complicated structure due to the presence of various copper clusters (tetramers, trimers). Moreover, the ESR spectra were anisotropic in an external magnetic field, despite originating from powder samples.
EN
Spectroscopic and magnetic data of the compound Cu(2-qic)2 .H2O (1), where 2-qic is quinoline-2-carboxylate in the light of the known X-ray structure were studied. The geometry of CuN2O3 chromophore shows a very distorted five-coordinate stereochemistry intermediate between tetragonal pyramid and trigonal bipyramid resulting from the didentate N,O-bonded two chelate ligands and one water molecule. The crystal structure is stabilized by extended hydrogen-bonding network. Magnetic data reflect the molecular character of the compound with very weak exchange interaction (zJ' = - 0.23 cm-1), transmitted through H-bonds. The physico-chemical properties of 1 are compared with a recently reported forms 2 and 3 of identical stoichiometries Cu(quinoline-2-carboxylate)2.H2O obtained in an unusual oxidative P-dealkylation reaction. The compound 1 was prepared directly from quinaldinic acid.
EN
New chromogenic azocrown ethers possessing sulfur atoms and two azo- groups in the macrocycle are described. The synthesized macrocycles have been applied as ion carriers in ion-selective membrane electrodes. Their selectivity and sensitivity were studied towards alkali and transition metal cations. Complexation of the compounds was studied by UV-Vis spectrophotometry in water-dioxane (1:1; v/v) solvent system. Stability constants of copper and silver complexes were determined. Contrary to oxygen analogues, the azothiacrowns do not form complexes with alkali or alkaline earth metal cations.
EN
The structure of diaquobis(m-trans hydrogen pyrazine-2,3-dicarboxylato N,O,O')copper(II) dihydrate crystals is polymeric. The coordination polyhedron around the Cu(II) ion is an elongated octahedron. The Cu(II) ion and two symmetry related pyrazine-2,3-dicarboxylate (2,3-PZDC) ligands are coplanar and form the basic unit of this structure. Each ligand coordinates the metal with one carboxylate oxygen atom [Cu-O(1) 1.957(3) A] and the nearest heteroring nitrogen atom [Cu-N(1) 2.000(3) A]. The second carboxylic group contributes one carbonyl oxygen atom that coordinates the Cu(II) ion in an adjacent unit [Cu-O(3) 2.414(4) A], giving rise to molecular ribbons composed of Cu(2,3-PZDC)2 units interconnected by oxygen atoms. The water molecules are involved in a system of hydrogen bonds operating between the ribbons.
EN
Molecular complex formation between guanosine (Guo) and biogenic amines: putrescine (Put), spermidine (Spd) and spermine (Spm) as well as coordination of these ligands with the copper(II) ions have been studied. It has been found that the positive centres of noncovalent ion-dipole interactions are the protonated amine groups of the polyamines, while the negative centres are the endocyclic nitrogen atoms N(7) or N(1) of guanosine. In the binary systems at low pH, the main site of noncovalent interaction and a metallation centre in guanosine is the nitrogen atom N(7). With deprotonation of N(1), the reaction centre shifts from N(7) to N(1). At high pH the nitrogen atom N(1) becomes the main centre of interactions between the nucleoside and polyamines (PA) and it also becomes an effective site of Cu(II) ions bonding. The addition of spermine to the Cu(II)/guanosine system leads to a disappearance of the coordination dichotomy observed in binary systems, whereas the introduction of putrescine and spermidine extends the range of the dichotomy to high pH values.
EN
It has been demonstrated that phenylcopper(I)-containing clusters are generated in the gas phase from bis(dibenzoylmethane) copper(II) (Cu(dbm)2) by laser desorption/ ionization (LDI) method. For example, the [Cu5dbm2(C6H5)2]+ ion can be considered as consisting of two Cudbm molecules, two CuC6H5 molecules and a Cu+ cation. The [Cu5(C6H5)4]+ ion can be considered as phenylcopper(I) cluster (consisting of four phenylcopper molecules) ionized by additional Cu+ cation. Results from MS/MS (tandem mass spectrometry) experiments have confirmed the presence of phenylcopper molecules in the analyzed clusters. Ease of preparation of dibenzoylmethane-metal complexes and straightforward method to obtain LDI mass spectra offer a wide range of possibilities to study similar organometallic clusters in the gas phase. [...]
EN
Several guanidinopyrimidine copper(II) complexes have been prepared in dimethylformamide (DMF) and characterized by elemental analysis, electronic, EPR and vibrational spectra and also by magnetic susceptibility measurements. The structure of the nearest environment of the central ion has been determined.
EN
Four new mixed complexes of Cu(II) with tpmc and bridge bound N,S or N,O ligands of the general formula. Elemental and thermal analyses, conductometric and magnetic measurements, electronic, IR and mass spectrscopy have been emplyed.
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Content available remote Electron spin resonance study of copper(II) hydrogenmalonate dihydrate complex
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EN
Copper(II) hydrogenmalonate dihydrate complex has been studied by using the electron spin resonance (ESR) method. Numerically deconvoluted ESR spectra of Cu(II) ions have been investigated at 4.2-295 K temperature range. The powder ESR spectrum has been described by three g-factors and additionally 1.5% of the existing spurious phases of a copper(II) complex has been revealed. The temperature dependence of the integrated ESR intensity has shown a Curic-Weiss type behaviour, consisting of two terms with different Curie-Weiss temperatures. The observed ferromagnetic interactions suggest the presence of two different paramagnetic species. It is proposed that the [Cu(H2O) 4][Cu(mal)2(H2O)2] copper(II) dimer complex is responsible for the low-temperature (T less than or equal 50 K) behaviour of the investigated sample.
EN
Joint spectroscopic (ESR, electronic absorption and FT IR) and voltammetric (squarewave and cyclic voltammetry) techniques were employed to investigate the properties of copper adducts with cysteine, N-acetylcysteine and methionine under aerobic and anaerobic conditions. The metal oxidation state in the solid and solvated adducts adheres to the presence of oxygen, whereas ESR results (g__ = 2.245, g_ = 2.059,A__= 170 Gauss) reveal tetragonally distorted octahedral copper(II) environment under aerobic circumstances. In presence of the thiol and thioether ligands under nitrogen voltammetric measurements evidence formation of copper(I) species.
EN
New complexes (PPh3)2M(S2COR) [R = sec.-butyl,M= copper (1), silver (2)] were synthesized by the reaction of excessive triphenylphosphine and copper(II) or silver(I) xanthate, and characterized using IR, EA, 1H NMR and TG. Their crystal structures have been determined by X-ray diffraction. The light yellow crystal of the complex (1) is triclinic of space group P1, with parameters a = 10.300(2) A, b = 13.120(3) A, c = 14.570(3)A, _= 89.53(3), _ = 72.81(3), _ = 78.61(3)_, and Z = 2. The yellow crystal of the complex (2) is triclinic of space group P1, with parameters a = 10.330(2) A, b = 13.410(3) A, c = 14.420(3) A, _ = 88.61(3), _ = 73.60(3), _ = 78.93(3)_, and Z = 2. In the two complexes, the central Cu or Ag atom is in a distorted tetrahedral environment and chelated by two phosphorus atoms from the triphenylphosphine groups and two sulfur atoms from the O-alkyldithiocarbonate. IR and 1H NMR results supported the structures. The thermal analytical data indicate that the complex (1) began to decompose at 122.3_ and decomposition was complete at 370.9_, leaving Cu2S, while the complex (2) began to decompose at 133.3_ and decomposed completely at 290.3_ to Ag2S.
EN
Disturbances in the balance between the rates of reactive oxygen species formation and the ability of cells to neutralize them are often cause dysfunction in the human body. Therefore the research on natural antioxidant systems protecting cells against destruction is very important. One of such system acting in human organism is superoxide dismutase (SOD), which is responsible for degradation of the superoxide radical anion into molecular oxygen and hydrogen peroxide. The SOD was discovered in the 40s of the twentieth century, and since then there has been a lot of research on it. Currently, these studies mainly concern searching compounds that may mimic the enzymatic activity of this protein. Groups of these compounds include, for example, peptides, salens, metalloporphyrins or vitamin derivatives. For the proper functioning of the CuZnSOD enzyme necessary is the active center containing metal ions (Rys.2). They mainly coordinate to the nitrogens of the imidazole histidine residues. Due to the fact that peptides may have many histidyl residues in their structure, they could rather than others coordinate with metal ions and they are promising compounds in studies on CuZnSOD mimetics. Therefore we will consider peptide complexes with copper(II) and zinc(II) ions as potential mimetics of superoxide dismutase. In presented review article we have focused on the differences in the coordination manner of divalent copper ions by linear, cyclic and branched peptides. As well as the possibility of creating hetero- and homo-dinuclear complexes are discussed. Moreover we have compared the ability of these complexes to decomposition the superoxide radical with activity of native enzyme.
EN
New Cu(II) complexes with triphenyl phosphite and aliphatic perfluorinated carboxylates [Cu{P(OC6H5)3}(u-OH)(u-RCOO)]n (where R=CF3, C2F5, C3F7, C6F13, C7F15, C8F17, C9F19) were obtainedf and their spectroscopic and thermal properties studied. EPR spectra and magnetic susceptibility measurments indicate the formation of polymeric complexes. Examination of COO absorption bands suggests bridging carboxylates as well as a hydro group, whereas triphenyl phosphite is monodentately bonded. Thermal decomposition is a multistage process, which in nitrogen yields a mixture of Cu, Cu2O and Cu2p2O7 but in air - pure u2P2O7.
17
Content available remote ESR study of spin dynamics in (Er0.5Y0.5)2Cu2O5 solid solution
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EN
Powder samples of (Er0.5Y0.5)2Cu 2O5 have been synthesized by a solid state reaction method. Electron spin resonance (ESR) measurements have been carried out on a Broker E 500 X-band spectrometer in the 4-300 K temperature range. A single, almost Lorentzian-shaped resonance line has been recorded for the whole investigated temperature range and its ESR parameters (integrated intensity, linewidth and resonance field) displayed a strong temperature dependence. The integrated intensity of the resonance line showed a pronounced maximum in low-temperature range and vanished at the transition to the antiferromagnetic ordering at TN = 11 K. The temperature at which the ESR integrated intensity reaches its maximum is different for the heating and cooling runs. Below 40 K, on approach to TN, the linewidth exhibited a divergent behaviour due to the onset of three-dimensional magnetic order. At higher temperatures (about 220 K), variations in ESR magnetic susceptibility suggest the presence of dynamical processes in copper-oxygen chains leading to the formation of copper dirners. The observed changes of the ESR parameters are interpreted in terms of 2D magnetism of the copper-oxygen system in the (Er 0.5Y0.5)2Cu2O5 solid solution.
EN
INTRODUCTION: The main limitation of the use of amphotericin B (AmB) – effective in the treatment of systemic fungal infections – is its high toxicity to human cells. The mechanism of AmB toxicity is not clear. Caspase-related and BCL-2 proteins participate in the regulation of apoptosis. Thus, they may be involved in drug toxicity. In this study we evaluated the influence of AmB on the transcriptional activity of genes related to caspases and the BCL-2 family. We also tested the influence of modified forms of AmB: AmB-Cu2+ (the complex with copper(II) ions) and the AmB-ox (oxidized form). MATERIAL AND METHODS: Human RPTECs (Renal Proximal Tubule Epithelial Cells) were treated with AmB, AmB-Cu2+ and AmB-ox. Total RNA was extracted using the phenol-chloroform method. The expression profiles of genes related to caspase activity and BCL-2 were determined using oligonucleotide microarrays (HG-U133A 2.0, Affymetrix). Analysis included 67 ID related to caspases and 32 ID associated with BCL-2, according to the Affymetrix database. RESULTS: The analysis revealed upregulation of the BCL-2 and BCL2L1genes in the cells treated with AmB-Cu2+, in comparison to the control. In both the AmB and AmB-Cu2+ -treated cells, differentiating genes were associated with inflammation and mitophagy activated by intrinsic signals. In the cells treated with AmB-ox, the BCL-2 genes were downregulated. CONCLUSIONS: The results suggest that AmB and AmB-Cu2+ activate genes involved in the regulation of inflam-mation and autophagy induced by intrinsic signals, but overexpression of BCL-2 and BCL2L1 may protect AmB-Cu2+--treated cells from death. In the cells treated with AmB-ox extrinsic signals prevail, indicating the distinct molecular mechanism of its cytotoxicity.
PL
WSTĘP: Głównym ograniczeniem stosowania amfoterycyny B (AmB) – skutecznej w leczeniu grzybic układowych – jest jej wysoka toksyczność wobec komórek ludzkich. Mechanizm cytotoksyczności nie został wyjaśniony. Białka związane z aktywnością kaspaz oraz białka należące do rodziny BCL-2 uczestniczą w regulacji apoptozy, mogą być zatem zaangażowane w procesy odpowiedzialne za toksyczność leku. W pracy oceniono wpływ AmB na aktywność transkrypcyjną genów kodujących białka związane z aktywnością kaspaz oraz białka z rodziny BCL-2. Zbadano również wpływ modyfikowanych form AmB: AmB-Cu2+ (kompleks z jonami miedzi (II)) i AmB-ox (formy utlenione). MATERIAŁ I METODY: Ludzkie komórki RPTECs (Human Renal Proximal Tubule Epithelial Cells) inkubowano z AmB, AmB-Cu2+ i AmB-ox. Całkowity RNA wyekstrahowano metodą fenolowo-chloroformową. Profil ekspresji genów wyznaczono techniką mikromacierzy oligonukleotydowych (HG-U133A 2.0, Affymetrix). Analiza obejmowała 67 ID genów związanych z aktywnością kaspaz i 32 ID geny kodujące białka z rodziny BCL-2, zaproponowane przez bazę Affymetrix. WYNIKI: Analiza wykazała nadekspresję genów BCL-2 i BCL2L1 w komórkach traktowanych AmB-Cu2+, w porównaniu z kontrolą. Zarówno w komórkach traktowanych AmB, jak i AmB-Cu2+ geny różnicujące związane były z za-paleniem i mitofagią aktywowanymi w odpowiedzi na sygnały wewnątrzkomórkowe. W komórkach traktowanych AmB-ox geny z rodziny BCL-2 były wyciszone. WNIOSKI: Wyniki sugerują, że AmB i AmB-Cu2+ aktywują geny zaangażowane w regulację zapalenia i mitofagii aktywowanych sygnałami wewnątrzkomórkowymi, jednak nadekspresja genów BCL-2 i BCL2L1 może chronić komórki traktowane AmB-Cu2+ przed śmiercią. W komórkach traktowanych AmB-ox przeważa sygnał zewnątrzkomórkowy, co wskazuje na odrębny mechanizm cytotoksyczności tej formy antybiotyku.
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Content available remote Związki kompleksowe jonów miedzi(II) z peptydami
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PL
W organizmach żywych jony różnych metali odgrywają ważną rolę w wiązaniu i transporcie molekuł organicznych oraz są katalizatorami różnych procesów (między innymi w reakcjach redoks i kwas-zasada). Białka są jedną z głównych grup substancji organicznych, z którymi łączą się jony metali. Dowodem na to jest istnienie i rola metaloenzymów. Prawdopodobieństwo silnego wzajemnego oddziaływania pomiędzy jonami metali a białkami ujawniono dzięki reakcji biuretowej. Jednak nadal mato jest dostępnych informacji na temat struktury i sposobu ich połączenia. Badania kompleksów metali z różnymi oligopeptydami miały znaczący udział w zrozumieniu interakcji między jonami metali a białkami. Miedź odgrywa bardzo ważną rolę w prawidłowym funkcjonowaniu organizmów żywych, w których występuje zarówno w postaci kationów jak i kompleksów. Dlatego też niniejszy artykuł będący przeglądem literaturowym dotyczy interakcji jonów miedzi(II) z peptydami.
EN
Metal ions play significant role in living organism. They are involved in binding, transportation of biological molecules and different catalytic processes. Proteins are one of the main organic substances bonding metal ions called metalloproteins. They have many different functions in cells, such as enzymes, transport and storage proteins, and signal transduction. Studies of metal complexes with oligopeptides have critical impact on understanding interactions between metal ions and proteins. Copper is virtually required by all organisms both as cations and complexes for biological processes such as respiration, iron transport, oxidative stress protection, peptide hormone production, pigmentation, blood clotting and normal cell growth and development. Therefore this review concerns interactions of Cu(II) with peptides and their analogues.
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