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Mitochondria, as “power house of the cell”, are crucial players in cell pathophysiology. Beyond adenosine triphosphate (ATP) production, they take part in a generation of reactive oxygen species (ROS), regulation of cell signaling and cell death. Dysregulation of mitochondrial dynamics may lead to cancers and neurodegeneration; however, the fusion/fission cycle allows mitochondria to adapt to metabolic needs of the cell. There are multiple data suggesting that disturbed mitochondrial homeostasis can lead to Parkinson’s disease (PD) development. 2-methoxyestradiol (2-ME), metabolite of 17β-estradiol (E2) and potential anticancer agent, was demonstrated to inhibit cell growth of hippocampal HT22 cells by means of nitric oxide synthase (NOS) production and oxidative stress at both pharmacologically and also physiologically relevant concentrations. Moreover, 2-ME was suggested to inhibit mitochondrial biogenesis and to be a dynamic regulator. This review is a comprehensive discussion, from both scientific and clinical point of view, about the influence of 2-ME on mitochondria and its plausible role as a modulator of neuron survival., Ministry of Science and Higher Education, Poland

The thermal stability of the oligomers obtained by using 2-chloro-2-propen-1-ol as the monomer has been studied. The oligomers were synthesized using chromium(III) and oxovanadium(IV) complexes as the catalysts after activation by modified methylaluminoxane (MMAO-12). The complexes used as the catalysts were polycarboxylate complex compounds of oxovanadium(IV) and chromium(III). The studies have been conducted by two methods: thermal gravimetry and differential scanning calorimetry. The obtained results allow to determine the glass transition temperatures and thermal stability of the oligomers depending on the central catalyst cation Cr3+ and V4+.

Elevated levels of reactive nitrogen species, alteration in redox balance and deregulated redox signaling are common hallmarks of cancer progression and chemoresistance. However, depending on the cellular context, distinct reactive nitrogen species are also hypothesized to mediate cytotoxic activity and are thus used in anticancer therapies. We present here the dual face of nitric oxide and its derivatives in cancer biology. Main derivatives of nitric oxide, such as nitrogen dioxide and peroxynitrite cause cell death by inducing protein and lipid peroxidation and/or DNA damage. Moreover, they control the activity of important protein players within the pro- and anti-apoptotic signaling pathways. Thus, the control of intracellular reactive nitrogen species may become a sophisticated tool in anticancer strategies.

Oxidative stress plays an important role in the pathogenesis of many serious diseases, including cancer, atherosclerosis, coronary artery disease, Parkinson’s disease, Alzheimer’s disease, stroke and myocardial infarction. In the body’s natural biochemical processes, harmful free radicals are formed, which can be removed with the help of appropriate enzymes, a balanced diet or the supply of synthetic antioxidant substances such as flavonoids, vitamins or anthocyanins to the body. Due to the growing demand for antioxidant substances, new complex compounds of transition metal ions with potential antioxidant activity are constantly being sought. In this study, four oxovanadium(IV) and dioxovanadium(V) dipicolinate (dipic) complexes with 1,10-phenanthroline (phen), 2,2′-bipyridyl (bipy) and the protonated form of 2-phenylpyridine (2-phephyH): (1) [VO(dipic)(H2O)2]·2 H2O, (2) [VO(dipic)(phen)]·3 H2O, (3) [VO(dipic)(bipy)]·H2O and (4) [VOO(dipic)](2-phepyH)·H2O were synthesized including one new complex, so far unknown and not described in the literature, i.e., [VOO(dipic)](2-phepyH)·H2O. The oxovanadium(IV) dipicolinate complexes with 1,10-phenanthroline and 2,2′-bipyridyl have been characterized by several physicochemical methods: NMR, MALDI-TOF-MS, IR, but new complex [VOO(dipic)](2-phepyH)·H2O has been examined by XRD to confirm its structure. The antioxidant activities of four complexes have been examined by the nitrotetrazolium blue (NBT) method towards superoxide anion. All complexes exhibit high reactivity with superoxide anion and [VOO(dipic)](2-phepyH)·H2O has higher antioxidant activity than L-ascorbic acid. Our studies confirmed that high basicity of the auxiliary ligand increases the reactivity of the complex with the superoxide radical.

The contemporary search for new catalysts for olefin oligomerization and polymerization is based on the study of coordinating compounds and/or organometallic compounds as post-metallocene catalysts. However known catalysts are suffered by many flaws, among others unsatisfactory activity, requirement of high pressure or instability at high temperatures. In this paper, we present a new catalyst i.e. the crystalline complex compound possesing high catalytic activity in the oligomerization of olefins, such as 2-chloro-2-propen-1-ol and ethylene under very mild conditions (room temperature, 0.12 bar for ethylene oligomerization, atmospheric pressure for 2-chloro-2-propen-1-ol oligomerization). New material - Cat-CrNP ( [nitrilotriacetato - 1,10–phenanthroline]chromium(III) tetrahydrate) has been obtained as crystalline form of the nitrilotriacetate complex compound of chromium(III) with 1,10-phenanthroline and characterized in terms of its crystal structure by the XRD method and by multi-analytical investigations towards its physicochemical propeties The yield of catalytic oligomerization over Cat-CrNP reached to 213.92 g ∙ mmol-1 ∙ h-1∙ bar-1 and 3232 g ∙ mmol-1 ∙ h-1 ∙ bar-1 for the 2-chloro-2-propen-1-ol and ethylene, respectively. Furthemore, the synthesis of Cat-CrNP is cheap, easy to perform and solvents used during preparation are environmentally friendly.

Characterization of polymers at various structural levels is very important because it aims, inter alia, to improve the properties of materials used on an industrial scale. Research on the structure and morphology of polymers allows for dependence between their macroscopic properties, morphology, and conformations, and for the interactions of polymer chains to be determined. Mechanistic studies examining the creation and interactions of polymer chains are used to plan the synthesis of new polymeric materials. Several analytical methods such as Scanning Transmission Electron Microscopy (STEM) in Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), Fourier Transform Infrared Spectroscopy (FTIR), and Nuclear Magnetic Resonance Spectroscopy (NMR) have been developed to characterize fractography, micro-deformation, nanostructures and self-organization of polymers in detail. In this review, the current status of analytical methods determining details of the structure, morphology and the reorganization of polymeric chains has been summarized.

A new chromium(III) complex with dipicolinate anion i.e. [Cr(dipic)(H 2 O) 3 ]Cl ⋅ 2 H 2 O and its crystal structure, the physicochemical properties and catalytic activity for the oligomerization reaction of 2-chloro-2-propen-1-ol is presented in this report. The X-ray analysis of the new chromium(III) complex has been performed and based on the X-Ray analysis the crystallographic parameters have been determined. Conductivity titrations have been performed to determine the stoichiometry of the complex in aqueous solutions. The stability of the titled compound in aqueous solutions has been examined by potentiometric titrations. The nitro blue tetrazolium test has been carried out to check the antioxidant properties of [Cr(dipic)(H 2 O) 3 ]Cl ⋅ 2 H 2 O. The oligomerization reaction of 2-chloro-2-propen-1-ol alcohol catalyzed by the titled chromium(III) complex has been conducted. The catalytic activity of [Cr(dipic)(H 2 O) 3 ]Cl ⋅ 2 H 2 O has been calculated. The oligomerization products have been characterized using the nuclear magnetic resonance spectroscopy, the matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry and the infrared spectroscopy.

The development of new polymerization methods and, consequently, the generation of new polymeric materials, is associated with the development of methods for testing the properties of these materials. The matrix assisted laser desorption and ionization - mass spectrometry method (MALDI-MS) is the technique used to study various polymers. The most important advantages of this method include the ability to determine the distribution of the molecular mass of polymers, identify the components of the polymer chain, and examine the surfaces of the polymers. The investigations using MALDI-MS are conducted on different types of samples, e. g. environmental samples, synthetic polymers, colony-cultured and blood-cultured samples. In this review the main recent developments of the MALDI-MS method for studies of polymers have been summarized. The future prospects in field of MALDI-MS and its application to different types of polymeric materials have been described.

The kinetics of the aquation reaction of the [VO(ida)(bipy)]·2H2O (VO(ida)(bipy)) complex (where ida = iminodiacetate anion and bipy = 2,2’-bipyridine) promoted by [Fe(H2O)6]3+ ions were investigated in aqueous solutions. Spectrophotometric studies were carried out at different temperatures in the range of 293.15–313.15 K. The concentration of the [Fe(H2O)6]3+ (Fe3+) ions was kept within the range of 2 × 10–4 to 8 × 10–4 mol L–1, and the concentration of VO(ida)(bipy) was 1 × 10–3 mol L–1. The values of the observable reaction rate constants were calculated based on the Glint computer program. Furthermore, the mechanism for the aquation of VO(ida)(bipy), induced by Fe(III) ions, has been proposed.

Polymers have a wide range of applications, in the production of packaging, medical and the automotive industries. Due to the ample and large-scale usage of polymers in various industries, scientists are now looking for novel polymer materials with thermoplastic properties or with the high mechanical strength while, maintaining a lightweight. Differential Scanning Calorimetry (DSC) based techniques such as conventional DSC, Parallel-Nano DSC (PNDSC), MicroElectroMechanical Systems (MEMS)-DSC, Modulated-Temperature DSC (MTDSC), Infrared (IR)-heated DSC, Gas Flow-Modulated DSC (GFMDSC), High-Performance (HPer) DSC, Pressure Perturbation Calorimetry (PPC), Flash DSC and Self-Referencing DSC (SRDSC) are frequently used to study and analyze the thermal properties of polymer materials. These techniques allow researchers to determine melting temperatures, polymorphic transformations and decompositions. This review highlights the recent developments within the field of DSC applications, which show new possibilities in the applications of DSC for physicochemical analysis.

Environmental contaminants, such as heavy metals, nanomaterials, and pesticides, induce the formation of reactive oxygen and nitrogen species (RONS). Plants interact closely with the atmosphere, water, and soil, and consequently RONS intensely affect their biochemistry. For the past 30 years researchers have thoroughly examined the role of RONS in plant organisms and oxidative modifications to cellular components. Hydrogen peroxide, superoxide anion, nitrogen(II) oxide, and hydroxyl radicals have been found to take part in many metabolic pathways. In this review the various aspects of the oxidative stress induced by environmental contamination are described based on an analysis of literature. The review reinforces the contention that RONS play a dual role, that is, both a deleterious and a beneficial one, in plants. Environmental contamination affects human health, also, and so we have additionally described the impact of RONS on the coupled human – environment system.

The report focuses on the new precatalysts for ethylene oligomerization. The five chromium(III) complex compounds containing the following ligands: dipicolinate anion, oxalate anion, 5-aminopyridine-2-carboxylate anion, 2,2′-bipyridine and 4,4′-dimethoxy-2,2′-bipyridine have been examined towards catalytic activity for ethylene oligomerization. The chromium(III) complexes have been activated by modified methylaluminoxane. The obtained oligomers have been investigated by MALDI-TOF–MS, thermal analysis and infrared spectroscopy. The results revealed that the examined chromium(III) complexes are highly active catalysts for ethylene oligomerization. The values of catalytic activities of the examined complexes are in the range 1860 – 3798 g∙mmol-1∙h-1∙bar-1.

2-methoxyestradiol (2-ME) is a physiological anticancer compound, metabolite of 17β-estradiol. Previously, our group evidenced that from mechanistic point of view one of anticancer mechanisms of action of 2-ME is specific induction and nuclear hijacking of neuronal nitric oxide synthase (nNOS), resulting in local generation of nitro-oxidative stress and finally, cancer cell death. The current study aims to establish the substantial mechanism of generation of reactive nitrogen species by 2-ME. We further achieved to identify the specific reactive nitrogen species involved in DNA-damaging mechanism of 2-ME. The study was performed using metastatic osteosarcoma 143B cells. We detected the release of biologically active (free) nitric oxide (•NO) with concurrent measurements of peroxynitrite (ONOO−) in real time in a single cell of 143B cell line by using •NO/ONOO− sensitive microsensors after stimulation with calcium ionophore. Detection of nitrogen dioxide (•NO2) and determination of chemical rate constants were carried out by a stopped-flow technique. The affinity of reactive nitrogen species toward the guanine base of DNA was evaluated by density functional theory calculations. Expression and localization of nuclear factor NF-kB was determined using imaging cytometry, while cell viability assay was evaluated by MTT assay. Herein, we presented that 2-ME triggers pro-apoptotic signalling cascade by increasing cellular reactive nitrogen species overproduction – a result of enzymatic uncoupling of increased nNOS protein levels. In particular, we proved that ONOO− and •NO2 directly formed from peroxynitrous acid (ONOOH) and/or by auto-oxidation of •NO, are inducers of DNA damage in anticancer mechanism of 2-ME. Specifically, the affinity of reactive nitrogen species toward the guanine base of DNA, evaluated by density functional theory calculations, decreased in the order: ONOOH > ONOO− > •NO2 > •NO. Therefore, we propose to consider the specific inducers of nNOS as an effective tool in the field of chemotherapy.

The oxydiacetate complexes of copper(II) with 2,2′-bipyridine (bipy) and 1,10-phenanthroline (phen) have been investigated towards their kinetic and thermodynamic stability. The kinetics of the substitution reactions of the oxydiacetate complex of Cu2+ with bipy and phen have been studied in two types of surfactant solutions - anionic dodecyl sulfate sodium (SDS) and cationic hexadecyl trimethyl-ammonium bromide (CTAB). The values of the observable rate constants for the studied reactions have been determined using the “Glint” program. Moreover, the thermodynamic stability of the copper(II) complexes with oda, phen and bipy in aqueous solutions has been investigated using potentiometric titration method (PT). The concentration distributions of the studied complexes as a function of pH calculated based on the values of log βpqrs have been determined. Additionally, the antioxidant activities of the oxydiacetate complexes of copper(II) with bipy and phen have been studied by the nitro blue tetrazolium (NBT) test and the cyclic voltammetry (CV) technique.

Breast cancer is the most common cancer of women—it affects more than 2 million women worldwide. PTP1B phosphatase can be one of the possible targets for new drugs in breast cancer therapy. In this paper, we present new curcumin derivatives featuring a 4-piperidone ring as PTP1B inhibitors and ROS inducers. We performed cytotoxicity analysis for twelve curcumin derivatives against breast cancer MCF-7 and MDA-MB-231 cell lines and the human keratinocyte HaCaT cell line. Furthermore, because curcumin is a known antioxidant, we assessed antioxidant effects in its derivatives. For the most potent cytotoxic compounds, we determined intracellular ROS and PTP1B phosphatase levels. Moreover, for curcumin and its derivatives, we performed real-time microscopy to observe the photosensitizing effect. Finally, computational analysis was performed for the curcumin derivatives with an inhibitory effect against PTP1B phosphatase to assess the potential binding mode of new inhibitors within the allosteric site of the enzyme. We observed that two tested compounds are better anticancer agents than curcumin. Moreover, we suggest that blocking the -OH group in phenolic compounds causes an increase in the cytotoxicity effect, even at a low concentration. Furthermore, due to this modification, a higher level of ROS is induced, which correlates with a lower level of PTP1B.

The kinetics and thermodynamics have been studied for the reactions of the copper(II) complexes with iminodiacetate (ida), 2,2′-bipyridine (bipy) and 1,10-phenanthroline (phen) as ligands. The kinetics of substitution reactions of two aqua ligands for bipy and phen in the [Cu(ida)(H2O)2] coordination compound has been studied in water and three type of aqueous solutions of the following surfactants: anionic sodium dodecyl sulfate (SDS), cationic hexadecyl trimethyl-ammonium bromide (CTAB) and nonionic t-octylphenoxypolyetoxyethanol (Triton X-100). The progress of the substitution reactions in the studied solutions was monitored spectrophotometrically using the stopped-flow method. The studies have allowed the determination of the effect of the type of surfactant solutions on the rate of the substitution reaction. Moreover, the order of studied reactions has been determined. The research performed has also allowed us to propose the reaction mechanism of the [Cu(ida)(H2O)2] binary complex with chelate ligands (bipy or phen). In addition, the thermodynamic stability of complexes under study in aqueous solutions has been examined using the potentiometric titration method. Moreover, the potential scavenging activity of the copper(II) complexes has been investigated towards the superoxide radical.

The crystal and molecular structures of a new dinuclear oxidovanadium(IV) complex with the N-(phosphonomethyl)iminodiacetate (pmida) ligand and the 4-amino-2-methylquinolinium ([amqH]+) cation of the molecular formula [amqH]4[V2O2(pmida)2]6H2O have been determined. The phosphonate groups in the two pmida4− ligands form two bridges between adjacent V4+ atoms, resulting in the formation of a [V2O2(pmida)2]4− dimer with a V2O4P2 eight-membered ring. This is the first example of a quinoline derivative complex containing the [V2O2(pmida)2]4− ion. The susceptibility curve for the complex exhibits a maximum at approximately 10 K, indicating the presence of antiferromagnetic interactions transmitted in the crystal lattice. Furthermore, the biological properties of the complex in the concentration range 1–100 μM were investigated in relation to its cytoprotective activity against oxidative damage generated exogenously using hydrogen peroxide in the hippocampal neuronal HT22 cell line (MTT tests). The obtained results were subsequently referred to the [amqH][VO(nta)(H2O)]H2O analogue as well as trolox and ascorbic acid, used as known antioxidants. It has been established that the title compound effectively protects HT22 from oxidative damage and is a potentially good candidate for further evaluation of the mechanism of its action.

New oxidovanadium(IV) complexes with a modification of the ligand in the VO 2+ coordination sphere were synthesized. [VO(mIDA)(dmbipy)]∙1.5H 2 O and [VO(IDA)(dmbipy)]∙2H 2 O were obtained as dark green crystals and grey-green powder, respectively (mIDA = N-methyliminodiacetic anion, IDA = iminodiacetic anion, dmbipy = 4,4′-dimethoxy-2,2′-dipyridyl). The crystal structure of [VO(mIDA)(dmbipy)]·1.5H 2 O has been determined by the X-ray diffraction method. The studies of structure of [VO(mIDA)(dmbipy)]∙1.5H 2 O have shown that this compound occurs in the crystal as two rotational conformers. Furthermore, the stability constants of [VO(mIDA)(dmbipy)]∙1.5H 2 O and [VO(IDA)(dmbipy)]∙2H 2 O complexes in aqueous solutions were studied by using the potentiometric titration method and, consequently, determined using the Hyperquad2008 program. Moreover, the title complexes were investigated as antioxidant substances. The impact of the structure modification in the VO 2+ complexes on the radical scavenging activity has been studied. The ability to scavenge the superoxide radical by two complexes - [VO(mIDA)(dmbipy)]·1.5H 2 O and [VO(IDA)(dmbipy)]·2H 2 O was studied by cyclic voltammetry (CV) and nitrobluetetrazolium (NBT) methods. The title complexes were also examined by the spectrophotometric method as scavengers of neutral organic radical - 1,1-diphenyl-2-picrylhydrazyl (DPPH ∙ ) and radical cation - 2,2'-azinobis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS ∙+ ). Furthermore, the biological properties of two oxidovanadium(IV) complexes were investigated in relation to its cytoprotective properties by the MTT and LDH tests based on the hippocampal HT22 neuronal cell line during the oxidative damage induced by hydrogen peroxide. Finally, the results presented in this paper have shown that the both new oxidovanadium(IV) complexes with the 4,4′-dimethoxy-2,2′-dipyridyl ligand can be treated as the cytoprotective substances.

The crystal and molecular structure of the new copper(II) complex with nitrilotriacetate (nta) and 1,10-phenanthroline (phen) ligands of the [Cu(phen)2Cu(nta)(phen)]2[Cu(Hnta)2]·20H2O molecular formula has been determined. The compound comprises the dianionic mononuclear entity, [Cu(Hnta)2]2−, and two monocationic dinuclear units, [Cu(phen)2Cu(nta)(phen)]+, in which the Cu(II) ions are bridged by one oxygen atom of the nta ligand in the rarely found μ1,1–O bridging mode. The complex was characterized by spectroscopic (IR, FIR and EPR) methods and magnetic measurements as well as thermogravimetry (TG). The magnetic measurements revealed an antiferromagnetic coupling between the Cu(II) ions in the dinuclear unit. Based on the experimental data supported by density functional theory (DFT) calculations the correlation between the coordination mode of the Cu(II) ions and magnetic properties of the compound studied has been discussed.

1,3-Diphenylisobenzofuran (DPBF) has been developed as a selective probe for the detection and quantitative determination of hydrogen peroxide in samples containing different reactive nitrogen and oxygen species (RNOS). DPBF is a fluorescent probe which, for almost 20 years, was believed to react in a highly specific manner toward some reactive oxygen species (ROS) such as singlet oxygen and hydroxy, alkyloxy or alkylperoxy radicals. Under the action of these individuals DPBF has been rapidly transformed to 1,2-dibenzoylbenzene (DBB). In order to check if DPBF can act as a unique indicator of the total amount of different RNOS, as well as oxidative stress caused by an overproduction of these individuals, a series of experiments was carried out, in which DPBF reacted with peroxynitrite anion, superoxide anion, hydrogen peroxide, hypochlorite anion, and anions commonly present under biological conditions, namely nitrite and nitrate. In all cases, except for hydrogen peroxide, the product of the reaction is DBB. Only under the action of H

The kinetics of the aquation reaction of [Ni(ODA)(H2O)3] (where ODA = oxydiacetate) promoted by [Fe(H2O)6]3+ ions were investigated. Spectrophotometry studies were carried out at temperatures within the range 293.15–313.15 K. The concentration of [Ni(ODA)(H2O)3] was 8.67 × 10–4 mol L–1 and the concentration of the [Fe(H2O)6]3+ ions was kept within the range 0.75 × 10–4–7.50 × 10–4 mol L–1. The observable reaction rate constants increased with the increase of [Fe3+] according to the rate law: kobs = k + k1K{[Fe(H2O)6]3+}. Based on the kinetic data, the activation parameters were determined for the spontaneous step of the reaction and for the step dependent on the concentration of Fe3+ ions. A mechanism for the aquation reaction has been proposed. In the first step (the reversible part of the aquation reaction) a dinuclear intermediate product is produced and in the next step the products of the reaction, ([Ni(H2O)6]2+ and [Fe(ODA)(H2O)3]+), are formed. Nevertheless, it has turned out that the spontaneous path of the aquation reaction is also possible concurrently (independent of the presence of Fe3+ ions). However, this process is too slow to be accurately measurable.

The influence of the oxydiacetate (ODA) and thiodiacetate (TDA) ligands on the physicochemical and biological properties of the oxidovanadium(IV) ternary complexes of the VO(L)(B) type, where L denotes ODA or TDA and B denotes 2,2'-bipyridine (bipy) or 1,10-phenanthroline (phen), has been investigated. The stability of the complexes in aqueous solutions, assessed based on the potentiometric titration method, increases in the following direction: VO(TDA)(bipy)

The crystal structure of 2,2′-bipyridyl(iminodiacetato)oxidovanadium(IV) dihydrate of [VO(IDA)bipy]·2H2O molecular formula was redetermined. The vanadium atom has an octahedral coordination. The IDA ligand adopts the facial conformation in VO(IDA)bipy. The stability of title compound in aqueous solutions was investigated by using the potentiometric titration method. Furthermore, the kinetics of substitution reactions of the [VO(IDA)H2O]H2O binary complex with 2,2′-bipyridine was investigated in aqueous solutions. These reactions were monitored spectrophotometrically using the stopped-flow method at 260 nm. The kinetic measurements were performed in the 293–308 K temperature range, at different concentrations in the 0.1–0.5 mM range of the binary complex and at the constant concentration of bipy (0.05 mmol/L). The antioxidant properties of [VO(IDA)bipy]·2H2O and [VO(IDA)H2O]H2O complexes have been studied. The antioxidant activity of these complexes against the superoxide radical as well as stable organic radicals, namely 1,1-diphenyl-2-picrylhydrazyl radical (DPPH ) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical was investigated. The evaluation of [VO(IDA)bipy]·2H2O as a potential antioxidant agent shows that the titled complex exhibit the antioxidant activity against the superoxide anion and organic radicals.

The kinetics of substitution reactions of the CuODA and CuTDA binary complexes (ODA = oxydiacetate, TDA = thiodiacetate) with 1,10-phenanthroline (phen) and 2,2’-bipyridine (bipy) were studied in aqueous and DMSO solutions. These reactions were monitored spectrometrically using the stopped-flow method in the UV range. The studies were carried out at three temperatures - 298.15, 303.15 and 308.15 K. The concentrations of the binary complexes were kept within the range of 0.2–0.5 mmol L−1, whereas the concentration of phen or bipy was constant = 0.05 mmol L−1. The values of the reaction rate constants were calculated based on the A → B reaction model. A linear relationship of the rate of the substitution reaction versus the concentration of the binary complex as well as temperature was observed. The impact of the type of the primary (ODA and TDA) and auxiliary ligands (phen and bipy) as well as the effect of solvent on the rate of substitution reaction have been discussed.

This publication presents a new chromium(III) complex with 5-aminopyridine-2-carboxylate anions. The title compound was characterized by single-crystal X-ray diffraction analysis, potentiometric and conductometric titrations. The oligomerization reaction of the 2-chloro-2-propen-1-ol alcohol was carried out using the title complex as a catalyst for the reaction. The resulting product was examined by MALDI-TOF MS and infrared spectroscopy. The catalytic activity of the complex in the oligomerization reaction of 2-chloro-2-propen-1-ol was determined.

This publication presents the new trends and opportunities for further development of coordination compounds used in the chemical industry. The review describes the influence of various physicochemical factors regarding the coordination relationship (for example, steric hindrance, electron density, complex geometry, ligand), which condition technological processes. Coordination compounds are catalysts in technological processes used during organic synthesis, for example: Oxidation reactions, hydroformylation process, hydrogenation reaction, hydrocyanation process. In this article, we pointed out the possibilities of using complex compounds in catalysis, and we noticed what further research should be undertaken for this purpose.

The oxydiacetate (oda) and iminodiacetate (ida) complexes of oxidovanadium(IV) with 1,10-phenantroline (phen) and 2,2′-bipyridine (bipy) have been synthesized. The six following complexes: [VO(oda)(H2O)2], [VO(oda)(bipy)]·2H2O, [VO(oda)(phen)]·1.5H2O, [VO(ida)(H2O)]·H2O, [VO(ida)(bipy)]·2H2O and [VO(ida)(phen)]·2H2O have been used as the new catalysts for the oligomerization of 2-chloro-2-propen-1-ol. The oligomerization process undergoes very easy at room temperature and under atmospheric pressure. All products of the oligomerizations have been studied with the several analytical methods such as the matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry (MALDI-TOF-MS), the nuclear magnetic resonance spectroscopy (NMR) and the thermogravimetric analysis (TGA) coupled with the analyzer of the infrared (IR) spectroscopy. The catalytic activities of the synthesized oxidovanadium(IV) complexes have been calculated which show that these complexes are the active catalysts in the 2-chloro-2-propen-1-ol oligomerization.

A coordination complex, [Co(ida)(H2O)2] where ida denotes iminodiacetate, as a potential highly active catalyst was designed and obtained. To obtain a full structural characteristic, i.e. to determine the crystallographic details and the spatial structure of the crystals of the studied complex, X-ray analysis was carried out. [Co(ida)(H2O)2] was investigated also by elementary analysis, IR spectrophotometry and MALDI-TOF-MS to get a full physicochemical characteristics. The stoichiometry of [Co(ida)(H2O)2] in aqueous solutions was determined using the conductometric titrations. Consequently, the potentiometric titrations were performed to determine the thermodynamic stability of the title compound in aqueous solutions. Moreover, the antioxidant activity of [Co(ida)(H2O)2] against superoxide anion radical has been examined by NBT test. The catalytic properties of the cobalt(II) complex, [Co(ida)(H2O)2], were examined. It turned out that complex studied is a highly active catalyst for the 2-chloro-2-propen-1-ol oligomerization. It catalyzes the reaction of oligomerization in mild conditions: under normal pressure and at room temperature. The oligomerization reaction products were fully characterized by the following spectroscopic methods: IR, NMR, MALDI-TOF-MS. Furthermore, to investigate the thermal behavior of the obtained oligomer, the product of the oligomerization obtained using [Co(ida)(H2O)2] as the catalyst was studied with the use of thermal analysis methods, i.e. DSC and TG. The catalytic activity of the title complex has also been calculated.

The new 2-pyridinecarboxylate (2-pic) complex of chromium(III) has been designed and synthesized as a new highly active and selective oligomerization catalyst. The crystal structure of the new compound has been determined by X-ray diffraction. The composition and purity of [Cr(2-pic)2(OH2)2]NO3 have been confirmed by several spectroscopic methods and the elemental analysis. Furthermore, the new complex has been investigated towards its catalytic activity for the oligomerization of 2-chloro-2-propen-1-ol under the atmospheric pressure and at room temperature. It has turned out that the novel catalyst exhibits a very high catalytic activity. Consequently, [Cr(2-pic)2(OH2)2]NO3 belongs to a new generation of non-metallocene catalysts.

Pancreatic ductal adenocarcinoma is one of the most aggressive human malignancies, where the 5-year survival rate is less than 4% worldwide. Successful treatment of pancreatic cancer is a challenge for today’s oncology. Several studies showed that increased levels of oxidative stress may cause cancer cells damage and death. Therefore, we hypothesized that oxidative as well as nitro-oxidative stress is one of the mechanisms inducing pancreatic cancer programmed cell death. We decided to use silver nanoparticles (AgNPs) (2.6 and 18 nm) as a key factor triggering the reactive oxygen species (ROS) and reactive nitrogen species (RNS) in pancreatic ductal adenocarcinoma cells (PANC-1). Previously, we have found that AgNPs induced PANC-1 cells death. Furthermore, it is known that AgNPs may induce an accumulation of ROS and alteration of antioxidant systems in different type of tumors, and they are indicated as promising agents for cancer therapy. Then, the aim of our study was to evaluate the implication of oxidative and nitro-oxidative stress in this cytotoxic effect of AgNPs against PANC-1 cells. We determined AgNP-induced increase of ROS level in PANC-1 cells and pancreatic noncancer cell (hTERT-HPNE) for comparison purposes. We found that the increase was lower in noncancer cells. Reduction of mitochondrial membrane potential and changes in the cell cycle were also observed. Additionally, we determined the increase in RNS level: nitric oxide (NO) and nitric dioxide (NO2) in PANC-1 cells, together with increase in family of nitric oxide synthases (iNOS, eNOS, and nNOS) at protein and mRNA level. Disturbance of antioxidant enzymes: superoxide dismutase (SOD1, SOD2, and SOD3), glutathione peroxidase (GPX-4) and catalase (CAT) were proved at protein and mRNA level. Moreover, we showed cells ultrastructural changes, characteristic for oxidative damage. Summarizing, oxidative and nitro-oxidative stress and mitochondrial disruption are implicated in AgNPs-mediated death in human pancreatic ductal adenocarcinoma cells.

The new type of catalysts designed for the olefin derivatives polymerization has been synthetized. The novel catalysts are chromium(III) salt type complexes composed of both organic cation and anion, i.e. [Cr(dipic)2][Cr(bipy)(dipic)H2O]∙2H2O and [Cr(dipic)2]Hdmbipy∙2.5 H2O. The compositions of these complexes have been confirmed by a number of instrumental methods including NMR, IR, UV-Vis, MS and elemental analysis ones. Moreover, the crystal structures of these novel catalysts were determined and reported. Furthermore, the [Cr(dipic)2][Cr(bipy)(dipic)H2O]∙2H2O and [Cr(dipic)2]Hdmbipy∙2.5H2O complexes have been studied towards their catalytic activity, after the activation by MMAO (modified methylaluminoxane), in the case of 2-chloro-2-propen-1-ol polymerization at 21 °C and atmospheric pressure. It has been found that novel catalysts, [Cr(dipic)2][Cr(bipy)(dipic)H2O]∙2H2O and [Cr(dipic)2]Hdmbipy∙2.5 H2O, exhibit a very high catalytic activity in the process of the polymerization of the beta-olefin derivatives. The products of a such catalyzed polymerization are the poly(allyl alcohol) derivatives.

The antioxidant properties of oxydiacetate complexes of cobalt(II) and nickel(II) with 1,10-phenantroline and 2,2′-bipyridine have been investigated towards the superoxide radical using the nitro blue tetrazolium chloride (NBT) test and the cyclic voltammetry (CV). Moreover, the biological activity of the complexes under study has been investigated in the Human Dermal Fibroblasts adult (HDFa) cell line. In the first step, the cytotoxic and the antiproliferative activities of the complexes were examined. Subsequently, the cytoprotective properties of the complexes have been investigated in an oxidative stress conditions induced by H2O2.

A new oxidovanadium(IV) complex was prepared by the reaction of vanadyl acetylacetonate [VO(acac)2], iminodiacetic acid (H2IDA) and 1,10-phenanthroline (phen) in aqueous solutions. The crystal structure of [VO(IDA)phen]·2H2O was determined by X-ray diffraction crystallographic analysis. The stability of the title compound in aqueous solution was investigated by using potentiometric titration methods. Moreover, the kinetics of substitution reactions of the VO(IDA) binary complex with 1,10-phenanthroline were investigated in aqueous solutions. These reactions were monitored spectrophotometrically at 249 nm by using stopped-flow methods. Kinetic measurements were performed in the 293–308 K temperature range, at different concentrations (0.1–0.5 mM) of the binary complex and at a constant concentration of phen (0.05 mmol/L). Moreover, the antioxidant properties of this complex against superoxide radicals were studied by nitrobluetetrazolium (NBT) and cyclic voltammetry (CV) and the antioxidant properties were also investigated against two organic radicals: the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·) and the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS·+) by using spectrophotometric methods. The results of the antioxidant tests show that VO(IDA)phen scavenges superoxide free radicals as well as organic radicals (ABTS·+ and DPPH·).

Detection and quantitative determination in biological media of the hydroxyl radical are of great importance due to the role this radical plays in many physiological and pathological processes. This review focuses on the progress that has been made in recent years in the development of fluorescent and luminescent probes employed to monitor hydroxyl radical concentrations under biological conditions.

Due to the biological significance of 4-hydroxy-TEMPO, its detection in biological systems such as blood serum is of great importance in both research and clinical applications. The following paper reports a novel fluorimetric method for the detection and quantitative determination of 4-hydroxy-TEMPO radicals in an aqueous solution using dihydroxycoumarins as fluorescent probes. Among the 17 coumarin derivatives studied, only some dihydroxycoumarins show high sensitivity, specificity and selectivity for 4-hydroxy-TEMPO. Among them, 6,7-dihydroxycoumarin (esculetin) exhibits the strongest fluorescence enhancement under the action of 4-hydroxy-TEMPO. In this assay, esculetin reacts with 4-hydroxy-TEMPO to exclusively yield a dimer. 6,7-Dihydroxycoumarin responds to 4-hydroxy-TEMPO quickly and shows a 2.5-fold fluorescence enhancement with an estimated detection limit of 285 μM.

The fluorescence quenching of norfloxacin, danofloxacin, enrofloxacin and levofloxacin, belonging to a group of fluoroquinolone antibiotics, by 4-hydroxy-TEMPO was studied in aqueous solutions with the use of steady-state, time-resolved fluorescence spectroscopy as well as UV-VIS absorption spectroscopy methods. In order to understand the mechanism of quenching the absorption and fluorescence emission spectra of all fluoroquinolone antibiotics studied as well as decreases of their fluorescence were registered as a function of the 4-hydroxy-TEMPO concentration. No deviations from a linearity in the Stern-Volmer plots (determined from both, steady-state and time-resolved measurements) were observed. The fluorescence quenching mechanism was proved to be totally dynamic, what was additionally confirmed by the registration of Stern-Volmer plots at 5 temperatures ranging from 15 to 55°C. On the basis of theoretical calculations of fluoroquinolones' molecular radii and ionization potentials the mechanism of electron transfer was rejected. It seems that the fluorescence quenching is diffusion-limited and is caused by the increase of nonradiative processes, such as internal conversion or intersystem crossing. The Stern-Volmer quenching constants and bimolecular quenching constants were determined at the room temperature for all fluoroquinolone antibiotics studied.

The isothermal titration calorimetry (ITC) technique supported by potentiometric titration data was used to study the interaction of zinc ions with pH buffer substances, namely 2-(N-morpholino)ethanesulfonic acid (Mes), piperazine-N,N'-bis(2-ethanesulfonic acid) (Pipes), and dimethylarsenic acid (Caco). The displacement ITC titration method with nitrilotriacetic acid as a strong, competitive ligand was applied to determine conditional-independent thermodynamic parameters for the binding of Zn(II) to Mes, Pipes, and Caco. Furthermore, the relationship between the proposed coordination mode of the buffers and the binding enthalpy has been discussed.

We have proposed a new method which can be applied in assessing the intracellular production of hydrogen peroxide. Using this assay we have examined the hydrogen peroxide generation during the L-glutamate induced oxidative stress in the HT22 hippocampal cells. The detection of hydrogen peroxide is based on two crucial reagents cis-[Cr(C2O4)(pm)(OH2)2]+ (pm denotes pyridoxamine) and 2-ketobutyrate. The results obtained indicate that the presented method can be a promising tool to detect hydrogen peroxide in biological samples, particularly in cellular experimental models.

The purpose of this study was to examine the application of the coordinated cis-[Cr(C2O4)(pm)(OH)2]+ cation where pm denotes pyridoxamine, as a specific sensing ion for the detection of hydrogen peroxide (H2O2). The proposed method for H2O2 detection includes two key steps. The first step is based on the nonenzymatic decarboxylation of pyruvate upon reaction with H2O2, while the second step is based on the interaction of cis-[Cr(C2O4)(pm)(OH2)2]+ with the CO2 released in the previous step. Using this method H2O2 generated during glutamate-induced oxidative stress was detected in HT22 hippocampal cells. The coordination ion cis-[Cr(C2O4)(pm)(OH2)2]+ and the spectrophotometric stopped-flow technique were applied to determine the CO2 concentration in cell lysates, supernatants and cell-free culture medium. Prior to CO2 assessment pyruvate was added to all samples studied. Pyruvate reacts with H2O2 with 1:1 stoichiometry, and consequently the amount of CO2 released in this reaction is equivalent to the amount of H2O2.

Potentiometric (PT) and conductometric (CT) titration methods have been used to determine the stoichiometry and formation constants in water for a series of ternary complexes of Co(II) and Ni(II) involving the oxydiacetate anion (ODA) and 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) ligands, namely [Co(ODA)(phen)(H2O)], [Co(ODA)(bpy)(H2O)], [Ni(ODA)(phen)(H2O)] and [Ni(ODA)(bpy)(H2O)]. The ternary complex formation process was found to take place in a stepwise manner in which the oxydiacetate ligand acts as a primary ligand and the phen or bipy ligands act as auxiliary ones. The stability of the ternary complexes formed is discussed in the relation to the corresponding binary ones. Furthermore, the kinetics of the substitution reactions of the aqua ligands in the coordination sphere of the Ni-ODA and Co-ODA complexes to phen or bipy were studied by the stopped-flow method. The kinetic measurements were performed in the 288–303 K temperature range, at a constant concentration of phen or bipy and at seven different concentrations of the binary complexes (4–7 mM). The influence of experimental conditions and the kind of the auxiliary ligands (phen/bipy) on the substitution rate was discussed.

The impact of oxydiacetate oxidovanadium(IV) complexes on plants is currently unknown. This report demonstrates the influence of these complexes on Arabidopsis thaliana (L.) Heynh. In the presence of 10−6M vanadium(IV) complexes, plants proceeded through their entire life cycle, with the occurrence of proper morphological and cytological organisation of leaf and root tissues. The addition of 10−1M H2O2 caused root damage, leaf necrosis, and plant death at around the seventh day, due to the destruction of the root system. Pretreatment of the plants with 10−6M of vanadium(IV) compounds: VOSO4 and VO(oda), alleviated the effects of H2O2 to some extent. Plants pretreated with 10−6M vanadium(IV) complexes survived longer despite the presence of H2O2. Considering the higher rate of plant survival in the presence of VOSO4, and the relatively high photosynthetic parameters and anthocyanin contents in the cells, we conclude that this vanadium(IV) compound can have positive effects on plants that are grown under stress conditions.