Ruthenium(IV) complexes as potential inhibitors of bacterial biofilm formation

With increasing antimicrobial resistance there is an urgent need for new strategies to control harmful biofilms. In this study, we have investigated the possibility of utilizing ruthenium(IV) complexes (H3O)2(HL1)2[RuCl6]·2Cl·2EtOH (1) and [RuCl4(CH3CN)2](L32)·H2O (2) (where L1-2-hydroxymethylbenzimadazole, L32-1,4-dihydroquinoxaline-2,3-dione) as effective inhibitors for biofilms formation. The biological activities of the compounds were explored using E. coli, S. aureus, P. aeruginosa PAO1, and P. aeruginosa LES B58. The new chloride ruthenium complexes were characterized by single-crystal X-ray diffraction analysis, Hirshfeld surface analysis, FT-IR, UV-Vis, magnetic and electrochemical (CV, DPV) measurements, and solution conductivity. In the obtained complexes, the ruthenium(IV) ions possess an octahedral environment. The intermolecular classical and rare weak hydrogen bonds, and π···π stacking interactions significantly contribute to structure stabilization, leading to the formation of a supramolecular assembly. The microbiological tests have shown complex 1 exhibited a slightly higher anti-biofilm activity than that of compound 2. Interestingly, electrochemical studies have allowed us to determine the relationship between the oxidizing properties of complexes and their biological activity. Probably the mechanism of action of 1 and 2 is associated with generating a cellular response similar to oxidative stress in bacterial cells

Zarządzanie przedsiębiorstwem górniczym w warunkach dynamicznych zmian na przykładzie Polskiej Grupy Górniczej SA

In Polish mining enterprises, mining exploitation processes are often carried out in much more difficult geological and mining conditions. At the same time, underground operation must be carried out in accordance with the legal requirements concerning work safety and public safety. In these circumstances, taking into account the fact that hard coal mining is by nature a less competitive industry, it should be stated that in Poland managing a mining enterprise is a real challenge. Additionally, in the situation of the functioning of mining enterprises in the conditions of the market economy and constant changes in the economic situation for coal, both on the domestic and foreign markets, the degree of management difficulties, including planning and decision making, is constantly increasing. This is a result of not only the specificity of mining production processes, but also the need to conduct effective economic activity in a constantly and dynamically changing environment. During the implementation of changes in a mining enterprise, the variety of conditions often increases difficulties in the change forecasting system and generates a high risk of implementing adaptive measures. The changes may have a different scope – from gradual, aimed at improving the activities carried out or slowly adapting to changes in the environment, through changes in implemented processes, to radical changes in functioning, often associated with organizational changes. This article aims to present the method of managing a mining enterprise, Poland Grupa Górnicza SA, established during the period of significant changes that took place at that time, both in the company itself and in the hard coal mining industry.W polskich przedsiębiorstwach górniczych procesy eksploatacji górniczej często są realizowane w trudnych warunkach geologiczno-górniczych. Równocześnie eksploatacja podziemna musi być prowadzona zgodnie z wymogami prawnymi, dotyczącymi zasad bezpieczeństwa pracy oraz bezpieczeństwa powszechnego. W tych okolicznościach, biorąc jednocześnie pod uwagę fakt, że górnictwo węgla kamiennego z natury rzeczy jest branżą mało konkurencyjną, należy stwierdzić, że w Polsce zarządzanie przedsiębiorstwem górniczym jest prawdziwym wyzwaniem. Dodatkowo, w sytuacji funkcjonowania przedsiębiorstw górniczych w warunkach gospodarki rynkowej oraz ciągłych zmian koniunktury na węgiel zarówno na rynku krajowym, jak i zagranicznym, stopień trudności zarządzania, w tym planowania i podejmowania decyzji, stale wzrasta. Jest to wynikiem nie tylko specyfiki prowadzenia procesów produkcji górniczej, ale także konieczności prowadzenia efektywnej działalności gospodarczej w ciągle i dynamicznie zmieniającym się otoczeniu. W trakcie wdrażania zmian w przedsiębiorstwie górniczym różnorodność uwarunkowań często piętrzy trudności w systemie przewidywania zmian oraz generuje wysokie ryzyko realizacji działań dostosowawczych. Zmiany mogą mieć różny zakres – od stopniowych, mających na celu udoskonalenie prowadzonych działań lub powolne dostosowywanie się do zmian otoczenia, poprzez zmiany realizowanych procesów, do radykalnych zmian funkcjonowania, często połączonych ze zmianami organizacyjnymi. Niniejszy artykuł ma na celu przedstawienie sposobu zarządzania przedsiębiorstwem górniczym, Polską Grupą Górniczą SA, powstałą w okresie znaczących zmian, jakie miały miejsce, zarówno w samej spółce, jak i w branży górnictwa węgla kamiennego

Purification of model biogas from toluene using deep eutectic solvents

Biogas from landfills and wastewater treatment facilities typically contain a wide range of volatile organic compounds (VOCs), that can cause severe operational problems when biogas is used as fuel. Among the contaminants commonly occur aromatic compounds, i.e. benzene, ethylbenzene, toluene and xylenes (BTEX). In order to remove BTEX from biogas, different processes can be used. A promising process for VOCs removal is their absorption in deep eutectic solvents (DES). In this work, three DES: ([ChCl] U TEG [choline chloride]:urea:tetraethylene glycol (1:2:2), [ChCl] U [choline chloride]:urea (1:2), [ChCl] DEG [choline chloride]:diethylene glycol (1:2)) and water were tested to toluene absorption in concentration of 2000 ppm v/v in nitrogen stream. The results demonstrated the high absorption capacity of toluene using DES based on glycols

Thermal behavior of manganese(II) complexes with pyridine-2,3-dicarboxylic acid

In this study, we analyzed influence of the type of the syntheses used: hydrothermal and non-hydrothermal on pyridine-2,3-dicarboxylic acid (2,3pydcH 2 ) coordina- tion fashion. Two manganese(II) complexes: [Mn(H 2 O) 3 (2,3pydc)] n ( 1 ) and [Mn(H 2 O) 6 ][Mn(2,3pydcH) 3 ] 2 ( 2 ) were successfully synthesized from the non-hydrothermal reac- tion system containing organic ligand and different Mn(II) salts. The received complexes have been prepared and characterized by spectroscopic (IR, Raman), structural (X-ray single crystal), and thermogravimetric methods. The results of the crystal study give some evidence that ligand exhibits various topological structures and interest- ing properties. Pyridine-2,3-dicarboxylic acid acts as monodicarboxylate N,O-chelating anion (complex 2 )ora doubly deprotonated three-dentate- N , O , O 0 dicarboxylate ion (complex 1 ). In the [Mn(H 2 O) 6 ][Mn(2,3pydcH) 3 ] 2 the coordination geometry around Mn(1) ion can be considered as being distorted octahedron {MnN 3 O 3 }. The Mn(2) cat- ion possesses the same coordination polyhedron (octahe- dral). We have also analyzed influence of furnace atmosphere on the thermal behavior and the kind of final product. The sample of ( 1 ) decomposes in four stages in N 2 (368–1073 K) and the final residue is MnO 2 . The ther- mogram of ( 2 ) exhibits three main distinct decomposition steps (383–973 K). A residue of MnO is remained. In both air and nitrogen atmosphere, Mn(II) complexes ( 1 ) and ( 2 ) keep unchanged over all steps of decomposition. Only the final residues are different (Mn 2 O 3 are formed). The course of pyrolysis and molecular structure of the complexes lead to the same conclusion about the strength of metal–ligand bonds. On the basis of the above results, it is concluded that the thermal stability of the manganese(II) compounds is slightly different

Ruthenium complexes in different oxidation states : synthesis, crystal structure, spectra and redox properties

The reactions of a mother solution of RuCl 3 with benzimidazole derivatives 2-(2 ’ -pyridyl)benzimidazole (2,2 ’ -PyBIm, L 1 ) and 2-hydroxymethylbenzimidazole (2-CH 2 OHBIm, L 2 ) yielded three novel ruthenium complexes: (H 2 L 1 ) 2 [Ru III Cl 4 (CH 3 CN) 2 ] 2 [Ru IV Cl 4 (CH 3 CN) 2 ]·2Cl·6H 2 O( 1 ), mer -[Ru III Cl 3 L 1 (CH 3 CN)]·L 1 ·3H 2 O( 2 ), and (HL 2 ) 4 [Ru IV Cl 6 ]·2Cl·4H 2 O( 3 ). The isolated compounds were characterised by elemental analyses, UV-Vis and IR spectroscopy, and magnetic measurements. The nature of the ligands bound to the metal ions of these compounds and the experimental conditions signi fi cantly in fl uenced the ruthenium com- plexes in di ff erent oxidation states. The N,N-donor ligand bound to the metal centre is a recognised stabiliser of the +III state of ruthenium, whereas the lack of ligand coordination promotes the formation of a mixed (Ru III /Ru IV ) complex. In the case of complex 3 , the absence of a N,O-donor ligand in the co- ordinate sphere facilitates the formation of the compound in a higher oxidation state. X-ray single crystal analyses revealed an octahedral geometry in each of the complexes. The crystal structure of ruthenium complexes is formed by a network of intermolecular classical and unconventional (C – H ⋯ π ) hydrogen bonds. The most interesting feature of the supramolecular architecture of complexes is the existence of a very rare Cl − ⋯ π interaction and π ⋯ π stacking, which also contribute to structural stabilisation. Ruthenium compounds 2 and 3 behave as paramagnets with an octahedral geometry, corresponding to the pres- ence of one or two unpaired electrons, respectively. The cyclic voltammetric data of complex 2 show three one-electron redox processes. The fi rst redox couple is reversible, whereas the two other couples have a quasi-reversible nature. In the case of complex 3 , two redox couples are reversible and the elec- trode processes are connected with exchange of one electron

Dimethyl ether (DME) as potential environmental friendly fuel

In recent years, there has been a growing interest in replacing petroleum fuels with so-called second generation environmental friendly fuels. Compared to traditional petroleum fuels dimethyl ether (DME) could be used as a clean high-efficiency compression ignition fuel with reduced particulate matter (PM), sulfur oxides (SOx), hydrocarbons (HC), carbon monoxide (CO) as well as combustion noise. Compared to some of the other leading alternative fuel candidates i.e., methane, methanol, ethanol, compressed natural gas, DME appears to have the largest potential impact on society including well-to-wheel greenhouse gas emissions, non-petroleum feedstocks, well-to-wheel efficiencies, fuel versatility, infrastructure, availability, economics, and safety and should be considered as the fuel of choice for eliminating the dependency on petroleum. This paper reviews the properties and the DME combustion effects on environmental and they were compared to diesel characteristic as well as the effect of blending DME with liquefied petroleum gas (LPG), conventional diesel fuel and biodiesel were discussed