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Wybrane właściwości fizykochemiczne polikarboksylanowych związków kompleksowych kobaltu(II), niklu(II), miedzi(II) i oksowanadu(IV)

Piotrowska-Kirschling A., Drzeżdżon J., Chmurzyński L., Jacewicz D.

Wiadomości Chemiczne

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2018

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[Z] 72, 11-12

797--814

EN

Cobalt(II), nickel(II), copper(II) and oxidovanadium(IV) cations are coordination centers in many polycarboxylate complexes [1‒16]. A number of coordination compounds of transition metal ions with such ligands as polycarboxylate anions and heterocyclic organic ligands, e.g. 1,10-phenanthroline (phen) or 2,2’-bipyridine (bipy) have been examined for their biological properties [3‒16]. Their selected structures and physicochemical properties have been described in the first chapter. The polycarboxylate coordination compounds of cobalt(II), nickel(II), copper(II) and oxidovanadium(IV) have interesting antioxidant, antibacterial and antifungal activities. The antioxidant properties of polycarboxylate complexes of Co(II), Ni(II), Cu(II) and VO(IV) with 4-picoline, 1,10-phenanhroline and 2,2’-bipyridine have been investigated towards the superoxide anion radical using the nitro blue tetrazolium chloride (NBT) test and the cyclic voltammetry (CV). Their antibacterial and antifungal activities have been tested against bacteria and fungus strains that are antagonistic to the human. The determined biological properties of the oxydiacetate Co(II), Ni(II), VO(IV) complexes with bipy/phen, the thiodiacetate VO(IV) and the iminodiacetate Cu(II) complexes have been compared with these of L-ascorbic acid, which is chemical compounds commonly used as the reference antioxidant substance. Consequently, the comparison of antioxidant properties of selected cobalt( II), nickel(II), copper(II) and oxidovanadium(IV) polycarboxylate compounds is described in this work (Section 3, Tab. 1‒4). The kinetics of substitution reactions of selected copper(II) polycarboxylate complex compounds were monitored using the stopped-flow method in various reaction conditions (concentration of complex, temperature, solvent) (Rys. 5‒6) [5, 6]. The obtained results of the kinetic studies of the substitution reactions of [Cu(tda)]n with 2,2’-bipyridine in aqueous surfactants solvents: sodium dodecyl sulfate (SDSaq) and hexadecyl trimethyl- ammonium bromide (CTABaq) at 298.15 K (25 °C) are presented.

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Krytyczne stężenie micelarne i metody jego wyznaczania

Piotrowska-Kirschling A., Drzeżdżon J., Chmurzyński L., Jacewicz D.

Wiadomości Chemiczne

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2018

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[Z] 72, 11-12

815--828

EN

Surfactants are substances, which have surface activity in aqueous solutions [1–3]. By adsorbing on the surface (boundary of phase separation) of the system, they change the surfactant properties of the liquid. Surfactants consist of a hydrophobic part (non-polar, called “tail”) and a hydrophilic part (polar, called “head”) [1–3]. The overall structure of the surfactant molecule is shown in Figure 1. In aqueous solution after exceeding one critical micellar concentration of the CMC surfatant (Critical Micelle Concentration), the surfactant molecules aggregate to form micelles [1–5]. Knowledge of CMC values and the micelle formation in solution, it determines the properties of surfactants and their subsequent use in the chemical industry. Surfactants are used in the chemical industry, inter alia, for the production of many detergents, cosmetics, paints, dyes, agrochemicals, pharmaceuticals, food or oil [2, 3].

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Właściwości antyoksydacyjne, antybakteryjne i przeciwgrzybicze związków kompleksowych miedzi(II)

Piotrowska A., Drzeżdżon J., Jacewicz D., Chmurzyński L.

Wiadomości Chemiczne

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2017

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[Z] 71, 3-4

219--240

EN

Since late 1930s copper has been recognized as an essential trace metal in living organisms. Copper(II) cation plays the role as a coordination center not only in the single-nuclear complexes, but also in the multinuclear coordination compounds with a particular emphasis on the polymers as ligands. The selected complex compounds of copper(II) with ligands which are organic and inorganic species have been characterized taking into account their physico-chemical properties. In addition, the complex compounds containing ligands such as Schiff ’s bases, hydrocarbons, organic bases, and also polycarboxylic anions: oxydiacetate, thiodiacetate, iminodiacetate and dipicolinate have been described considering their role in the biological systems. Nowadays tested coordination compounds of copper(II) have interesting antibacterial activities against bacteria strains that are antagonistic to the human. The antibacterial activity of copper(II) complex is stronger than some of the known antibacterial substances e.g. ciprofloxacin. In addition, copper(II) complex compounds exhibit a 64-fold greater antimicrobial properties than copper(II) chloride. Moreover, these compounds have antifungal and antioxidant properties. The activities of antibacterial, antifungal, and antioxidant complex compounds of copper( II) have been compared to the reactivities of these compounds with complexes used as reference substances, e.g. L-ascorbic acid, in the assay using nitrotetrazolium blue.

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Probing of Cu2+ ions binding to A β (5−16) peptide using ITC measurements and MD simulations

Makowska J., Żmudzińska W., Wyrzykowski D., Brzozowski K., Zblewska H., Chmurzyński L.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2016

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Vol. 20, No 4

409--416

EN

It is shown that probably three residues: His6, His14 and His16 in the original sequence A β (1−42) serve as metal-binding sites for Cu2+ions. On the other hand, there is a possibility that only one of them plays a crucial role in the formation of the{A β (1-42)-Cu2+} complex. The isothermal titration calorimetry (ITC) measurements supported by molecular dynamic simulation (MD) with the NMR-derived restrains were used to investigate the interactions of Cu2+ with A β(5-16), a fragment of the A β(1-42) protein, with the following sequence: Ac-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Lys-NH2, termed HZ1. The conditional thermodynamic parameters suggest that the formation of the Cu2+-HZ1 complex is both an enthalpy and entropy driven process under the experimental conditions. The studies presented here (after comparison with our previous results) show that the affinity of peptides to copper metal ions depends on two factors: the primary structure (amino acid composition) and the shape of the peptide conformation adopted.

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Conformational analysis of fragment of human Pin1 ww domain: influence of charged amino-acid residues on β-hairpin structure

Makowska J., Uber D., Żmudzińska W., Chmurzyński L.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2014

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Vol. 18, No 4

343--349

EN

We examined the effect of like-charged residues on the conformation of an original nine amino-acid-residue fragment of the human Pin1 WW domain (hPin1) with the f ollowing sequence: Ac-Arg-Met-Ser-Arg-Ser-Ser-Gly-Arg-Val-NH 2 (U9). This was facilitated by CD and NMR spectroscopic measurements, and molecular dynamics calculations. Our ear lier studies suggested that the presence of like-charged residues at the end of a shor t polypeptide chain composed of nonpolar residues could induce a chain reversal. For the U9 pep tide, canonical MD simulations with NMR -derived restraints demonstrated the presence of ensembles of stru ctures with a tendency to form a β -chain reversal. Additionally, thermal stabilities of the peptide und er study were measured using differential scanning calorimetry ( DSC ). The estimated well defined phase transition point showed that conformational equilibria in the U9 pe ptide were strongly dependent on temperature.

6

Investigation of Tetrahalogenoferrates(III) with Cations of Nitrogen-Containing Organic Bases. X-ray Crystal Structure of 2,6-Dimethylpyridinium Tetrabromoferrate(III)

Wyrzykowski D., Kruszyński R., Styczeń E., Chmurzyński L.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 8

1503--1511

EN

The crystal and molecular structure of a new 2,6-dimethylpyridinium tetra bromo -ferrate(III), [2,6-LutH][FeBr4] was determined. The iron(III) cation adopts a slightly distorted tetrahedral coordination with one angle smaller than tetrahedral, three almost equal to the tetrahedral ones and two larger. The bond valences were computed. The total valence of the iron atom is equal to 3.24. In the structure N(1)–H(1)×××Br(3) hydrogen bond can be found.

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Ab initio Study of the Energetics of Protonation and Cationic Homoconjugation of Trimethylamine

Makowski M., Makowska J., Chmurzyński L.

Polish Journal of Chemistry

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2003

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Vol. 77 / nr 11

1447-1459

EN

Ab initio methods at the RHF (Restricted Hartree Fock) and MP2 (Moller-Plesset) levels were used to study the energetics of protonation of trimethylamine and its derivative trimethylamine N-oxide, as well as the energetics of formation of hydrogen bonded (NźźźHźźźN)+ and (OźźźHźźźO)+ type, respectively, homocomplexed cations. The Gaussian functional basis sets 3-21G, 6-31G, 6-311G, 6-31G* and 6-31+G*were employed to calculate energy and Gibbs free energy of protonation and cationic homoconjugation in the gas phase and with the inclusion of solvation effects (usingPCMmethod). The calculated energetic parameters in the gas phase and in solution, as well as experimental values of equilibrium constants of the acid dissociation and cationic homoconjugation reaction for trimethylamine and trimethylamine N-oxide systems provided a basis for a comparison of the basicity and tendency towards cationic homoconjugation of both compounds under study. Consequently, the acid-base properties of aliphatic bases have been compared with those of heterocyclic bases containing both oxygen and nitrogen.

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A potentiometric Study of the Cationic Homoconjugation Equilibria in Substituted Pyridine N-Oxide Systems in Binary Polar Solvents, Acetonitrile-Nitromethane

Wróbel R., Makowski M., Chmurzyński L.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 4

619-622

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A Comparison of Basicities of Substituted Pyridines and Pyridine N-Oxides

Makowski M., Kozak A., Chmurzyński L.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 4

581-588

EN

The basicity of pyridine and its derivatives, as representatives of monocyclic heterocyclic N-bases, has been compared with that of pyridine N-oxide and its derivatives representing the class of heterocyclic monocyclic oxygen-containing bases. The basicities have been compared both in the gas phase and in solution. To do this, correlated were both calculated (at RHF, MP2 levels and using SCRF and PCM methods) energy parameters, _Eprot and _Gprot, with experimental pKa values for a particular class of the bases, as well as theoretical and experimental characteristics of the two classes of compounds studied. Results of the correlations paved the way to discussion of the effect of the medium on basicity of both classes of compounds, as well as enabled to compare the basicities of these very important classes of organic bases in a quantitative way.

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The Influence of Solvent in Binary Acetonitrile -Water Solvent Systems on Dissociation Constants of Protonated Pyridine and Its N-Oxide

Wróbel R., Makowski M., Czaja M., Chmurzyński L.

Polish Journal of Chemistry

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2001

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Vol. 75, nr 11

1767-1774

EN

Using a 2,6-dinitrophenol - tetra-n-butylammonium 2,6-dinitrophenolate standardizing system, the application of the previously proposed method for pKa determination of potentiometric standards in binary solvent systems consisting of an organic polar solvent (acetonitrile in this case) and water was checked. The reliability of the obtained pKa values of 2,6-dinitrophenol was checked in a system of protonated pyridine in acetonitrile - water mixtures over the range of 0 through 1 mole fraction of acetonitrile, for which literature data were available. The method checked in this way was subsequently used to determine pKa of protonated pyridine N-oxide in this binary solvent system. pKa values served for discussion of the variations of pKa's of cationic acids conjugated with pyridine and its N-oxide and of the influence of composition of the binary solvent.