Publication in Polymers

25. August 2021

Publication entitled "Application of Furcellaran Nanocomposite Film as Packaging of Cheese" (authors: A. Pluta-Kubica, E. Jamróz, G. Khachatryan, A. Florkiewicz, P. Kopel) has been published in the journal Polymers.

There is a serious need to develop and test new biodegradable packaging which could at least partially replace petroleum-based materials. Therefore, the objective of this work was to examine the influence of the recently developed furcellaran nanocomposite film with silver nanoparticles (obtained by an in situ method) on the quality properties of two cheese varieties: a rennet-curd (gouda) and an acid-curd (quark) cheese. The water content, physicochemical properties, microbiological and organoleptic quality of cheese, and migration of silver nanoparticles were examined. The film improved the microbiological quality of cheeses during storage. Consequently, it is worth continuing research for the improvement of this film in order to enable its use in everyday life.


Publication in International Journal of Nanomedicine

 25. August 2021

Publication entitled "The Anti-Proliferative Activity of Coordination Compound-Based ZnO Nanoparticles as a Promising Agent Against Triple Negative Breast Cancer Cells" (authors: H. Stepankova, M. Swiatkowski, R. Kruszynski, P. Svec, H. Michalkova, V. Smolikova, A. Ridoskova, Z. Splichal, P. Michalek, L. Richtera, P. Kopel, V. Adam, Z. Heger, S. Rex) has been published in the medical journal International Journal of Nanomedicine.

The present study deals with the in vitro evaluation of the potential use of coordination compound-based zinc oxide (ZnO) nanoparticles (NPs) for the treatment of triple negative breast cancer cells (TNBrCa). Prepared by reacting zinc carboxylates and hexamethylenetetramine, 4 distinct coordination compounds were further subjected to two modes of conversion into ZnO NPs - ultrasonication with oleic acid or heating of pure precursors in an air atmosphere. The resulting ZnO NPs provide distinct morphological features, size, biocompatibility, and selective cytotoxicity toward TNBrCa cells. The crucial properties of ZnO NPs seem to be their morphology, size, and zinc content. The ZnO NPs with the most preferential values of all three properties show great promise for a future potential use in the therapy of TNBrCa.

Publication in Journal of Nanobiotechnology

 25. August 2021

Publication entitled " Mutual influence of selenium nanoparticles and FGF2-STAB® on biocompatible properties of collagen/chitosan 3D scaffolds: in vitro and ex ovo evaluation" (authors: J. Muchová, V. Hearnden, L. Michlovská, L. Vištejnová, A. Zavaďáková, K. Šmerková, S. Kočiová, V. Adam, P. Kopel, L. Vojtová) has been published in the biotechnology journal Journal of Nanobiotechnology .

In vitro and ex ovo biocompatibility of naturally based crosslinked freeze-dried 3D porous collagen/chitosan scaffolds, modified with thermostable fibroblast growth factor 2 (FGF2-STAB(R)), to enhance healing and selenium nanoparticles (SeNPs) to provide antibacterial activity, were evaluated.

The scaffolds were further subjected to antimicrobial tests, where an increase in selenium concentration in the collagen/chitosan scaffolds increased the antibacterial activity. This work highlights the antimicrobial ability and biocompatibility of newly developed crosslinked collagen/chitosan scaffolds involving FGF2-STAB(R) and SeNPs. Moreover, we suggest that these sponges could be used as scaffolds for growing cells in systems with low mechanical loading in tissue engineering, especially in dermis replacement, where neovascularization is a crucial parameter for successful skin regeneration. Due to their antimicrobial properties, these scaffolds are also highly promising for tissue replacement requiring the prevention of infection.

Publication in Chemistry A European Journal

Journal cover 24. August 2021

Publication entitled "Chiral Resolution of Spin-Crossover Active Iron(II) [2x2] Grid Complexes" (authors: N. Suryadevara, A. Pausch, E. Moreno-Pineda, A. Mizuno, J. Bürck, A. Baksi, T. Hochdörffer, I. Šalitroš, A. S. Ulrich, M. M. Kappes, V. Schünemann, W. Klopper, M. Ruben ) has been published in the chemistry journal Chemistry A European Journal.

The article describes the preparation, structural and magnetic properties of two tetranuclear ferrous complexes – optical isomers, which are both showing the spin crossover magnetic bistability. The oustdanding results of this work are based on the controlling of the spin crossover properties by the optical isomerism. A bis-tridentate N-donor ligand has been used for the preparation of both ferrous tetranuclear [2+2] grids, where the used ligand can coordinate in the Lambda or Delta configuration. The magnetic properties investigation revealed that both optical isomers are showing almost identical thermal spin crossover, but they show the differences in the photoinduced spin transition properties.

Publication in Dalton Transactions

Journal cover 23. August 2021

Publication entitled "A multifunctional magnetic material based on a solid solution of Fe(II)/Co(II) complexes with a macrocyclic cyclam-based ligand" (authors: B. Drahoš, I. Šalitroš, I. Císařová, R. Herchel) has been published in the chemistry journal Dalton Transactions.

In order to prepare a multifunctional magnetic material combining spin crossover together with single-molecular magnetism, co-crystallization of Fe(II) and Co(II) complexes of the pyridine derivative of cyclam (Py2-C = 1,8-bis(pyridin-2-ylmethyl)-1,4,8,11-tetraazacyclotetradecane) was performed. Complexes with the general formula [MII(Py2-C)](ClO4)2·H2O (MII = Fe (1), Co (2) or Fe0.4Co0.6 (3)) were prepared and thoroughly characterized. Based on X-ray molecular structures, they formed octahedral complexes with cis-arrangement of the coordinated pyridine moieties. Magnetic data revealed that the Fe(II) complex 1 shows complete SCO with the transition temperature T1/2 = 141 K, which is preserved also in the mixed Fe/Co system 3 (T1/2 = 128 K). Co(II) complex 2 behaves as a field-induced single-molecule magnet as well as the mixed system 3 with a direct and phonon bottleneck relaxation process, respectively.

Publication in Dalton Transactions

Journal cover 15. July 2021

Publication entitled " Solvent-induced structural transformation from heptanuclear to decanuclear [Co–Ln] coordination clusters: trapping of unique counteranion and understanding of aggregation pathways" (authors: D. Basak, E. R. Martí, M. Murrie, I. Nemec, D. Ray) has been published in the chemistry journal Dalton Transactions.

In this paper, we report on synthesis and crystal structure of three decanuclear CoII/III-LnIII complexes, which were prepared from heptanuclear precursors by solvent induced aggregation. It was revealed that the aggregation was induced by removal of the methoxido bridging ligands, which were substituted by hydroxido ligands.

Student publication in Dalton Transactions

Journal cover 15. June 2021

Publication entitled "Unexpected solution behaviour of ester-functionalized half-sandwich Ru(II) and Ir(III) complexes" (authors: L. Masaryk, I. Nemec, J. Kašpárková, V. Brabec, P. Štarha) has been published in the chemistry journal Dalton Transactions.

In this work, we studied the solution behaviour of two half-sandwich Ru(II) and Ir(III) complexes bearing the ester-functionalized 2,2′-bipyridine-based ligand. It was proved that the nature of ester substituent (acetate vs. dichloroacetate) affects the in-solution stability of the ester bond. The experiments performed in the presence of porcine liver esterase (PLE) indicated that although free ester-based ligand was readily metabolized by PLE (acetate release was observed), both complexes containing this ligand were not cleaved by PLE, meaning distinctly different affinity of the used enzyme to the substrate (ligand) when involved in the studied complexes.

Publication in Dalton Transactions

Journal cover09. June 2021

Publication entitled "Thermo- and photoinduced spin state switching in an iron(ii) 2D coordination network associated with large light-induced thermal hysteresis and tuning of dimensionality via ligand modulation" (authors: S. Ghosh, S. Kamilya, T. Pramanik, A. Mohanty, M. Rouzières, R. Herchel, S. Mehta, A. Mondal ) has been published in the chemistry journal Dalton Transactions.

In this work, three Fe(II) coordination compounds were investigated, while by examining the magnetic properties of [Fe(L2)2(NCS)2]n (3) (L2 = 2,5-diethynylpyridinyl-3,4- ethylenedioxythiophene) it was confirmed that the change in spin state is caused by the change in temperature, i.e. it is a spin crossover compound. Photomagnetic experiments confirmed the possibility of switching the spin state even by exposure to light. The study was also supported by theoretical calculations such as DFT, TD-DFT and CASSCF explaining the magnetic and spectroscopic properties of these substances.

Student publication in Polyhedron as cover

Journal cover31. May 2021

Publication entitled "Triple M as Manganese: Medicine, magnetism and macrocycles. Seven-coordinate Mn(II) complexes with pyridine-based macrocyclic ligands" (authors: E. Zahradníková, I. Císařová, B. Drahoš) has been published in the chemistry journal Polyhedron. Moreover, the picture describing this work was chosen as a cover artwork for the corresponding issue of the jurnal.

In this work, 3 structurally new ligands L1-L3 derived from a 17-membered macrocyclic ligand with pyridine and piperazine group and their manganese complexes were prepared. Based on the results of X-ray structural analysis, the prepared complexes were found as seven-coordinate with close to the pentagonal bipyramidal geometry. The Mn-Naliphatic bond distances in the equatorial plane were significantly lengthened up to 2.61Å.

Publication in Dalton Transactions

Journal cover12. May 2021

Publication entitled "An unexpected in-solution instability of diiodido analogue of picoplatin complicates its biological characterization" (authors: P. Štarha, B. Drahoš, R. Herchel) has been published in the chemistry journal Dalton Transactions.

In this work, we investigated the solution behaviour of biologically prospective complex cis-[PtI2(NH3)(pic)] (pic = 2-methylpyridine), a diiodido analogue of clinically studied Pt-based drug picoplatin (cis-[PtCl2(NH3)(pic)]). We proved both experimentally and theoretically that cis‑[PtI2(NH3)(pic)] is, in contrast to picoplatin, unstable in solution, where it undergoes several processes, including the release of its N-donor pic ligand. This observation complicates the cytotoxicity testing of this Pt(II) diiodido complex.

Publication in Dalton Transactions

Journal cover19. April 2021

Publication entitled "Hydroxido supported and differently networked octanuclear Ni6Ln2 [Ln = GdIII and DyIII] complexes: structural variation, magnetic properties and theoretical insights" (authors: A. Bhanja, L. Smythe, R. Herchel, I. Nemec, M. Murrie, D. Ray) has been published in the chemistry journal Dalton Transactions.

In this work, the magnetic properties of two hexanuclear coordination compounds [Gd2Ni6L43-OH)6(μ-OH)2(CH3CO2)2(μ-H2O)2(H2O)3(MeOH)]·8H2O (1) and [Dy2Ni6L43-OH)4(μ-Cl)2Cl4(H2O)2(MeOH)2]·2MeOH·4H2O (2) prepared with the same ligand - Schiff base H2L = 2 - {[(2-hydroxy-3-methoxybenzyl) imino] methyl} phenol, were investigated. Inspection of the magnetic properties revealed a dominant ferromagnetic exchange interaction in compound 1 and compound 2 was identified as a single molecule magnet. The study was supported by theoretical calculations such as DFT and CASSCF leading to the elucidation of exchange interactions and magnetic anisotropy in these complexes.

Publication in Coordination Chemistry Reviews

Journal cover10. February 2021

Publication entitled "Multinuclear biologically active Ru, Rh, Os and Ir arene complexes" (author: P. Štarha) has been published in the chemistry journal Coordination Chemistry Reviews.

In this review, multinuclear biologically active complexes derived from half-sandwich ruthenium(II), rhodium (III), osmium(II) and iridium(III) arene moieties have been reported. Besides homometallic Ru, Rh, Os and Ir complexes, heterometallic compounds containing the mentioned platinum metals in combination with other d-block elements are discussed as well. Special attention was paid to the comparison of structurally similar analogues differing in the number or type of metal centres.

Publication in Inorganic Chemistry

Journal cover15. December 2020

Publication entitled "Reversible Spin-State Switching and Tuning of Nuclearity and Dimensionality via Nonlinear Pseudohalides in Cobalt(II) Complexes" (authors: S. Ghosh, S. Kamilya, M. Rouzières, R. Herchel, S. Mehta, A. Mondal ) has been published in the chemistry journal Inorganic Chemistry.

Herein, we report on investigations of magnetic, spectroscopic and electrochemical properties of two Co(II) coordination compounds with N,N-di-tert-butyl-2,11-diaza[3,3](2,6)pyridinophane macrocyclic ligand. Complex 1 exhibits a high-spin (S = 3/2) state of cobalt(II) with a large magnetic anisotropy. Interestingly, complex 2 exhibits reversible spin-state switching (T1/2 = 321 K).

Publication in Dalton Transactions

Journal cover29. October 2020

Publication entitled "From solid state to in vitro anticancer activity of copper(II) compounds with electronically-modulated NNO Schiff base ligands" (authors: L. Rigamonti, F. Reginato, E. Ferrari, L. Pigani, L. Gigli, N. Demitri, P. Kopel, B. Tesarova, Z. Heger) has been published in the chemistry journal Dalton Transactions.

The copper(II) complexes of general formula [Cu(GL)(Cl)] (13, G = OMe, H and NO2, respectively), bearing tridentate Schiff base ligands (GL) and a chloride as a fourth labile one, are here reported. The Schiff bases derive from the monocondensation of ethylenediamine and substituted salicylaldehyde, where the electronic properties are modulated by the releasing or withdrawing power of the G group. The compounds were structurally characterized through single crystal Synchrotron X-ray diffraction experiments in the solid state. In vitro tests on cell viability were conducted on malignant cell lines. All compounds were capable of formation of intracellular reactive oxygen species and DNA intercalation. This is especially effective for 3 (NO2), which revealed the highest anticancer activity against malignant triple-negative breast cancer MDA-MB-231 cells.

Publication in Nanomaterials

29. October 2020

Publication entitled "Synergistic Effect of Chitosan and Selenium Nanoparticles on Biodegradation and Antibacterial Properties of Collagenous Scaffolds Designed for Infected Burn Wounds" (authors: J. Dorazilová, J. Muchová, K. Šmerková, S. Kočiová, P. Diviš, P. Kopel, R. Veselý, V. Pavliňáková, V. Adam, L. Vojtová) has been published in the journal Nanomaterials.

A highly porous scaffold is a desirable outcome in the field of tissue engineering. The porous structure mediates water-retaining properties that ensure good nutrient transportation as well as creates a suitable environment for cells. In this study, porous antibacterial collagenous scaffolds containing chitosan and selenium nanoparticles (SeNPs) as antibacterial agents were studied. The addition of antibacterial agents increased the application potential of the material for infected and chronic wounds. The morphology, swelling, biodegradation, and antibacterial activity of collagen-based scaffolds were characterized systematically to investigate the overall impact of the antibacterial additives. The additives visibly influenced the morphology, water-retaining properties as well as the stability of the materials in the presence of collagenase enzymes. Even at concentrations as low as 5 ppm of SeNPs, modified polymeric scaffolds showed considerable inhibition activity towards Gram-positive bacterial strains such as Staphylococcus aureus and methicillin-resistant S. aureus and S. epidermidis.

Publication in Dalton Transactions

10. September 2020

Publication entitled " Co(ii)-Based single-ion magnets with 1,1′-ferrocenediyl-bis(diphenylphosphine) metalloligands" (authors: J. Hrubý, D. Dvořák, L. Squillantini, M. Mannini, J. van Slageren, R. Herchel, I. Nemec, P. Neugebauer ) has been published in the chemistry journal Dalton Transactions.

Herein, we report on investigations of magnetic and spectroscopic properties of three heterobimetallic Fe(II)–Co(II) coordination compounds based on the tetracoordinate {CoP2X2} core encapsulated by dppf metalloligand, where X = Cl (1), Br (2), I (3), dppf = 1,1′-ferrocenediyl -bis(diphenylphosphine). The analysis of static magnetic data has revealed the presence of axial magnetic anisotropy in compounds (1) and (2) and this was further confirmed by high-frequency electron spin resonance (HF-ESR) spectroscopy. Dynamic magnetic data confirmed that (1) and (2) behave as field-induced Single-Ion Magnets (SIMs). Together with bulk studies, we have also tested the possibility of depositing (2) as thick films on Au(111), glass, and polymeric acetate by drop-casting as well as thermal sublimation, a key aspect for the development of future devices embedding these magnetic objects.

Endowment Fund of Palacký University supported our student

17. july 2020

Ph.D. student of Inorganic Chemie Mgr. Marie Pražáková received a finantial support from Endowment fung of Palacky University.

Mgr. Marie Pražáková, a first-year doctoral student in Inorganic Chemistry, succeeded and received a financial support from the UP Endowment Fund, which will be very beneficial for solving her research project called Research of Contrast Agents for MRI (Magnetic Resonance Imaging).

More details can be found on the webpage of the Faculty of Science or UP Endowment Fund.

Congratulations to Marie and we wish her much success in solving the project.

(Mgr. Pražáková second from the right)

Publication in Dalton Transactions

8. july 2020

Publication entitled "Late first-row transition metal complexes of a 17-membered piperazine-based macrocyclic ligand: structures and magnetism." (authors: E. Zahradníková, R. Herchel, I. Šalitroš, I. Císařová, B. Drahoš) has been published in the chemistry journal Dalton Transactions.

The 17-membered piperazine-based macrocyclic ligand LdiProp (1,5,13,17,22-pentaazatricyclo[,11]docosa-7,9,11(22)-triene) was resynthesized in high yield with help of linear pump. Its Mn(II), Fe(II), Co(II) and Ni(II) complexes of general formula [MnLdiProp(ClO4)2] (1), [FeLdiProp(CH3CN)](ClO4)2 (2), [CoLdiProp(CH3CN)](ClO4)2 (3), [NiLdiProp](ClO4)2 (4) were prepared and thoroughly characterized. X-ray diffraction analysis confirmed that Mn(II) complex 1 has capped trigonal prismatic geometry with coordination number seven, Fe(II) and Co(II) complexes 2 and 3 are trigonal prismatic with coordination number six and Ni(II) complex 4 has square pyramidal geometry with coordination number five. The decrease of coordination number is accompanied by a shortening of M–N distances and an increase of torsion of piperazine ring from the equatorial plane. Magnetic measurement reveal moderate for 4 and rather large magnetic anisotropy for 2 and 3 (axial zero-field splitting parameter D(Ni) = 9.0 cm–1, D(Fe) = –14.4 cm–1, D(Co) = –25.8 cm–1, together with rather high rhombicity). Co(II) complex 3 behaves as field-induced SMM with a combination of Raman and direct or Orbach and direct relaxation mechanisms. Obtained magnetic data were extensively supported by theoretical CASSCF calculations. The flexibility and rather large 17-membered macrocyclic cavity of ligand LdiProp could be responsible for the variation of coordination numbers and geometries for investigated late-first row transition metals.