@u-szeged.hu
Department of Inorganic, Organic and Analytical Chemistry
University of Szeged
Inorganic Chemistry, Physical and Theoretical Chemistry, Spectroscopy
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Rebeka Mészáros, Vivien Szabó, Bence Kutus, Kornélia Baán, Zoltán Kónya, Ákos Kukovecz, Pál Sipos, and Márton Szabados
Elsevier BV
Eszter Kása, Yvette Szabó, Márton Szabados, Ákos Kukovecz, Zoltán Kónya, Pál Sipos, and Bence Kutus
Elsevier BV
Adél Anna Ádám, Szilveszter Ziegenheim, László Janovák, Márton Szabados, Csaba Bús, Ákos Kukovecz, Zoltán Kónya, Imre Dékány, Pál Sipos, and Bence Kutus
MDPI AG
Anionic surfactants, such as sodium linear alkylbenzene sulfonates (NaLAS), are utilized in various fields, including industry, household, and agriculture. The efficiency of their use in aqueous environments is significantly affected by the presence of cations, Ca2+ and Mg2+ in particular, as they can decrease the concentration of the surfactant due to precipitation. To understand cation–sulfonate interactions better, we study both NaLAS colloidal solutions in the presence of CaCl2 and precipitates forming at higher salt concentrations. Upon addition of CaCl2, we find the surface tension and critical micelle concentration of NaLAS to decrease significantly, in line with earlier findings for alkylbenzylsulfonates in the presence of divalent cations. Strikingly, an increase in the surface tension is discernible above 0.6 g L–1 NaLAS, accompanied by the decrease of apparent micelle sizes, which in turn gives rise to transparent systems. Thus, there appears to be a second critical concentration indicating another micellar equilibrium. Furthermore, the maximum salt tolerance of the surfactant is 0.1 g L–1 Ca2+, above which rapid precipitation occurs yielding sparingly soluble CaLAS2∙2H2O.
Bence Kutus, Kenneth Wagner, Manfred Wagner, and Johannes Hunger
Elsevier BV
Éva Böszörményi, Orsolya Dömötör, Bence Kutus, Gábor Varga, Gábor Peintler, and Pál Sipos
Elsevier BV
Éva Böszörményi, Zsolt Kása, Gábor Varga, Zoltán Kele, Bence Kutus, Gábor Peintler, István Pálinkó, and Pál Sipos
Elsevier BV
Yang Yao, Sara Catalini, Bence Kutus, Johannes Hunger, Paolo Foggi, and Raffaele Mezzenga
Wiley
Abstract We investigate the static and dynamic states of water network during the phase transitions from double gyroid (Ia3‾d ) to double diamond (Pn3‾m ) bicontinuous cubic phases and from the latter to the reverse hexagonal (H II) phase in monolinolein based lipidic mesophases by combining FTIR and broadband dielectric spectroscopy (BDS). In both cubic(s) and H II phase, two dynamically different fractions of water are detected and attributed to bound and interstitial free water. The dynamics of the two water fractions are all slower than bulk water due to the hydrogen‐bonds between water molecules and the lipid's polar headgroups and to nanoconfinement. Both FTIR and BDS results suggest that a larger fraction of water is hydrogen‐bonded to the headgroup of lipids in the H II phase at higher temperature than in the cubic phase at lower temperature via H‐bonds, which is different from the common expectation that the number of H‐bonds should decrease with increase of temperature. These findings are rationalized by considering the topological ratio of interface/volume of the two mesophases.
Eszter Kása, Márton Szabados, Kornélia Baán, Zoltán Kónya, Ákos Kukovecz, Bence Kutus, István Pálinkó, and Pál Sipos
Elsevier BV
Bence Kutus, Andrey Shalit, Peter Hamm, and Johannes Hunger
Royal Society of Chemistry (RSC)
Dielectric relaxation experiments on light, heavy-, and heavy-oxygen water reveal that classical mass effects on the reorientational relaxation of water can be accounted for by a translational mass factor.
Bence Kutus, Csilla Dudás, Sergej Friesen, Gábor Peintler, István Pálinkó, Pál Sipos, and Richard Buchner
American Chemical Society (ACS)
Sodium citrate (Na3Cit) has a crucial role in many biological and industrial processes. Yet, quantitative information on its hydration and the ion association between Na+ and Cit3- ions in a broad range of salt concentrations is still lacking. In this work, we study both ion association equilibria and relaxation dynamics of sodium citrate solutions by combining potentiometry, spectrophotometry, and dielectric spectroscopy. From photometric and potentiometric measurements, we detect the formation of the NaCit2- ion-pair and the neutral Na3Cit0 ion aggregate in a wide range of ionic strengths (0.5-4 M). Due to its remarkable stability, the latter becomes the prevailing species at higher salt concentrations. In the dielectric spectra, we observe the dipolar relaxation of Cit3- and NaCit2- and two solvent-related processes, associated with the collective rearrangement of the H-bond network (cooperative water mode) and the H-bond flip of water molecules (fast water mode). Unlike numerous other salt solutions, the relaxation time of the cooperative mode scales with the viscosity indicating that the strongly hydrated anion fits well into the water network. That is, the stabilizing effect of anion-solvent interactions on the H-bond network outweighs the destructive impact of the cations as the latter are only present at low concentration, due to strong ion association. In conclusion, the affinity of citrate toward Na+ binding not only governs solution equilibria but also has a strong impact on water dynamics.
Ákos Buckó, Zsolt Kása, Márton Szabados, Bence Kutus, Ottó Berkesi, Zoltán Kónya, Ákos Kukovecz, Pál Sipos, and István Pálinkó
MDPI AG
In the present work, the structure and thermal stability of Ca–Al mixed-metal compounds, relevant in the Bayer process as intermediates, have been investigated. X-ray diffraction (XRD) measurements revealed the amorphous morphology of the compounds, which was corroborated by SEM-EDX measurements. The results of ICP-OES and UV-Vis experiments suggested the formation of three possible ternary calcium aluminum heptagluconate (Ca-Al-Hpgl) compounds, with the formulae of CaAlHpgl(OH)40, Ca2AlHpgl2(OH)50 and Ca3Al2Hpgl3(OH)90. Additional IR and Raman experiments revealed the centrally symmetric arrangement of heptagluconate around the metal ion. The increased thermal stability was demonstrated by thermal analysis of the solids and confirmed our findings.
Éva Böszörményi, Jorge Lado, Csilla Dudás, Bence Kutus, Márton Szabados, Gábor Varga, István Pálinkó, and Pál Sipos
Walter de Gruyter GmbH
Abstract Certain complexing agents (such as D-gluconate, D-isosaccharinate, etc.) as well as actinides and lanthanides are simultaneously present in cementitious radioactive waste repositories and (in the presence of water) are capable of forming complex compounds. Such processes may immobilize radionuclides and are of importance in the thermodynamic modelling of the aqueous chemistry of waste repositories. Nd(III) is considered to be a suitable model for trivalent lanthanides and actinides, due to the similarity of their ionic radii. In the current work, solid complexes isolated from aqueous solution containing Nd(III), Ca(II) and D-gluconate (Gluc−) were investigated. In an aqueous solution containing Nd(III) and Gluc−, the formation of a precipitate was observed at pH ≥ 8. This precipitate was found to redissolve around pH ~ 11, but reprecipitated when Ca(II) ions were added to the solution. In order to gain an insight in binary and ternary aqueous systems, in the present work we report the structure of these solid complexes obtained from XRD, FT-IR, Raman, SEM-EDAX and UV-DRS measurements. The structure of these solids, where possible, was compared with those identified in solution. The compositions of these complexes are suggested to be NdGlucH−1(OH) · 2H2O and CaNdGlucH−1(OH)3 · 2H2O, respectively. In these, the chemical environment of the Nd(III) was found to be the same as that in the NdGlucH−1(OH)0(aq) solution species.
Ákos Buckó, Bence Kutus, Gábor Peintler, Zoltán Kele, István Pálinkó, and Pál Sipos
Elsevier BV
Bence Kutus, Jun Zhu, Jian Luo, Qi‐Qiang Wang, Alexandru Lupan, Amr A. A. Attia, De‐Xian Wang, and Johannes Hunger
Wiley
Abstract Tritopic ion‐pair receptors can bind bivalent salts in solution; yet, these salts have a tendency to form ion‐pairs even in the absence of receptors. The extent to which such receptors can enhance ion pairing has however remained elusive. Here, we study ion pairing of M2+ (Ba2+, Sr2+) and X− (I−, ClO4 −) in acetonitrile with and without a dichlorooxacalix[2]arene[2]triazine‐related receptor containing a pentaethylene‐glycol moiety. We find marked ion association already in receptor‐free solutions. When present, most of the MX+ ion‐pairs are bound to the receptor and the overall degree of ion association is enhanced due to coordinative, hydrogen‐bonding, and anion‐π interactions. The receptor shows higher selectivity for iodides but also stabilizes perchlorates, despite the latter are often considered as weakly coordinating anions. Our results show that ion‐pair binding is strongly correlated to ion pairing in these solutions, thereby highlighting the importance of taking ion association in organic solvents into account.
Bence Kutus, Xavier Gaona, Attila Pallagi, István Pálinkó, Marcus Altmaier, and Pál Sipos
Elsevier BV
Bence Kutus, Csilla Dudás, Eszter Orbán, Alexandru Lupan, Amr A. A. Attia, István Pálinkó, Pál Sipos, and Gábor Peintler
American Chemical Society (ACS)
The complexation equilibria between Mg2+ and d-gluconate (Gluc–) ions are of particular importance in modeling the chemical speciation in low- and intermediate-level radioactive waste repositories. NMR measurements and potentiometric titrations conducted at 25 °C and 4 M ionic strength revealed the formation of the MgGluc+, MgGlucOH0, MgGluc(OH)2–, and Mg3Gluc2(OH)40 complexes. The trinuclear species provides indirect evidence for the existence of multinuclear magnesium(II) hydroxido complexes, whose formation was proposed earlier but has not been confirmed yet. Additionally, speciation calculations demonstrated that MgCl2 can markedly decrease the solubility of thorium(IV) at low ligand concentrations. Regarding the structure of MgGluc+, both IR spectra and density functional theory (DFT) calculations indicate the monodentate coordination of Gluc–. By the potentiometric data, the acidity of the water molecules is higher in the MgGluc+ and MgGlucOH0 species than in the Mg(H2O)62+ aqua ion. On the basis of DFT calculations, this ligand-promoted hydrolysis is caused by strong hydrogen bonds forming between Gluc– and Mg(H2O)62+. Conversely, metal-ion-induced ligand deprotonation takes place in the case of calcium(II) complexes, giving rise to salient variations on the NMR spectra in a strongly alkaline medium.
Csilla Dudás, Bence Kutus, Éva Böszörményi, Gábor Peintler, Amr A.A. Attia, Alexandru Lupan, Zoltán Kele, Pál Sipos, and István Pálinkó
Elsevier BV
Ákos Buckó, Bence Kutus, Gábor Peintler, István Pálinkó, and Pál Sipos
Elsevier BV
V. Bugris, Cs. Dudás, B. Kutus, V. Harmat, K. Csankó, S. Brockhauser, I. Pálinkó, Peter Turner, and P. Sipos
International Union of Crystallography (IUCr)
The single-crystal structures of calcium D-gluconate and calcium α-D-isosaccharinate have been determined using X-ray diffraction at 100 K. Surprisingly, given its significance in industrial and medical applications, the structure of calcium D-gluconate has not previously been reported. Unexpectedly, the gluconate crystal structure comprises coordination polymers. Unusually, the calcium coordination number is nine. Adjacent metal centres are linked by three μ-oxo bridges, with a metal–metal separation of 3.7312 (2) Å. One of the gluconate ligands contradicts a suggestion from 1974 that a straight chain conformation is associated with an intramolecular hydrogen bond. This ligand binds to three adjacent metal centres. The use of synchrotron radiation provided an improved crystal structure with respect to that previously reported for the isosaccharinate complex, allowing the location of the hydroxy hydrogen sites to be elucidated. In contrast to the gluconate structure, there are no μ-oxo bridges in the isosaccharinate coordination polymer and the isosaccharinate bridging coordination is such that the distance between adjacent metal centres, each of which is eight-coordinate, is 6.7573 (4) Å. Complementing the crystal structure determinations, modelling studies of the geometries and coordination modes for the aqueous [CaGluc]+ and [CaIsa]+ complexes are presented and discussed.
Csilla Dudás, Bence Kutus, Gábor Peintler, István Pálinkó, and Pál Sipos
Elsevier BV
Bence Kutus, Gábor Peintler, Ákos Buckó, Zsolt Balla, Alexandru Lupan, Amr A.A. Attia, István Pálinkó, and Pál Sipos
Elsevier BV
Bence Kutus, Csilla Dudás, Gábor Peintler, István Pálinkó, and Pál Sipos
Elsevier BV
C. Dudás, B. Kutus, É. Böszörményi, G. Peintler, Z. Kele, I. Pálinkó, and P. Sipos
Royal Society of Chemistry (RSC)
During the interactions of α-d-isosaccharinate andd-gluconate with Ca2+in aqueous solution, differences rather than similarities prevail.
Bence Kutus, Norbert Varga, Gábor Peintler, Alexandru Lupan, Amr A. A. Attia, István Pálinkó, and Pál Sipos
Royal Society of Chemistry (RSC)
The structure and stability constants of four mononuclear and two, so far unknown and highly stable binuclear complexes have been determined.
Bence Kutus, Dániel Ozsvár, Norbert Varga, István Pálinkó, and Pál Sipos
Royal Society of Chemistry (RSC)
Besides the well-known ML species, Ca(ii) forms ML2 complexes with carbohydrates having at least one carboxylate group and conformational flexibility.