Bonyolult komplex vegyületek előállítása, szerkezetük, tulajdonságaik vizsgálata spektroszkópiai, diffrakciós és elméleti módszerekkel = Multicomponent coordination compounds: synthesis and studies of structure and properties by using spectroscopic, diffraction and theoretical methods

Geokémiai és bio-szervetlen kémia fontosságú Al3+-ligandum (F?, oxalát, citrát, glifozát, edta) rendszerekben multinukleáris NMR és kvantumkémiai módszerrel (DFT) jellemeztük a komplexek egyensúlyi és szerkezeti viszonyait, az inter- és intra-molekuláris cserefolyamatokat. B. Előállítottunk új, csupasz fém-fém kötést tartalmazó vegyületeket: {(CN)5Pt-Tl(CN)x}x? (x=0-3),{(CN)5Pt-Tl-Pt(CN)5}3?, {(CN)5Pt-Tl(APK}x? (APK = aminopolikarboxilát, pl. edta, nta, mimda) és M(I)2M(II)Hg(CN)6?2H2O (M(I)= Na vagy K, M(II)=Ni, Pd, Pt). NMR, Raman, IR, UV-VIS, XPS spektroszkópia és röntgen diffrakció segítségével meghatároztuk a vegyületek szerkezetét, a komplexek egyensúlyi állandóit, a fém-fém kötés képződésének sebességi egyenletét. C. Leírtuk néhány a Mo(VI)-H+-H2O2-ligandum rendszerben képződő - izopoliperoxo anion egyensúlyi és szerkezeti viszonyait, értelmeztük a Mo(VI) katalitikus hatását a környezetbarát peroxiddal való oxidáció során. | Equilibria, structure and inter- and intra-molecular exchange reactions of Al3+-ligand (F?, oxalate, citrate, glyphosate, edta) systems having geochemical and bio inorganic importance were studied by multiNMR and quantum chemical calculations (DFT). B. New platinum-thallium cyano compounds with a ""naked"" metal-metal bond has been prepared: {(CN)5Pt-Tl(CN)x}x? (x=0-3), {(CN)5Pt-Tl-Pt(CN)5}3?, {(CN)5Pt-Tl(APK}x? (APK = aminopolycarboxylate, i.e. edta, nta, mimda) and M(I)2M(II)Hg(CN)6?2H2O (M(I)= Na or K, M(II)=Ni, Pd, Pt). Structure, equilibrium, formation kinetics of the compounds were studied by NMR, Raman, IR, UV-VIS and XPS spectroscopy, EXAFS and X-ray. C. Equilibria and structure of some isopoly-peroxo species in Mo(VI)-H+-H2O2-ligand system were determined. Catalytic effect of Mo(VI) in the environmentally friendly oxidation reactions with H2O2 could be explained

Új többmagvú főcsoportbeli- és átmenetifém-komplexek előállítása, szerkezetük, fizikai tulajdonságaik és reaktivitásuk vizsgálata. = Novel metal complexes of some main group and transition elements: preparation and study of structure, physical and chemical properties

Összetett fémion– ligandum rendszerek koordinációs kémiai leírását végeztük el, ami kiterjedt a komplexek egyensúlyi állandói, a szerkezet és kötés, az izomerizáció mechanizmusának meghatározására. Multinukleáris NMR, UV-VIS spektroszkópia, ESI-MS, pH-potenciometria, EXAFS jelentették a kísérleti módszereket, amihez részletes elméleti számolások, a DFT alkalmazása kapcsolódott. Legfontosabb eredményeknek az Al(edta)- komplex enantiomerizációja mechanizmusának leírását, az Al(III)- etiléndiamin-N,N?-bis(3-hidroxi-2-propionát) dimer komplex, az Al(III)-N-foszfonometil-glicin monomer, dimer és trimer komplexeinek és az extrém stabilis Tl(III)DOTA komplex egyensúlyi állandóinak és szerkezetüknek a meghatározását, új Pt-Tl fém-fém kötést tartalmazó (CN)5Pt-Tl(aminopolikarboxilát) és (CN)4Pt-Tl(dmso)5+ komplexeknek vizes ill. dmso oldószerben való előállítását és karakterizálását, a (CN)5Pt-Tl-Pt(CN)53- komplex fotokémiai bomlásának, valamint a V(V)-peroxid rendszer ionos folyadékban való viselkedésének jellemzését tekintjük. | Characterisation of complicated metal ion-ligand systems including determination of stability constants, structure and bonding, mechanisms of isomerisation have been done by using of multinuclear NMR, UV-VIS spectroscopy, ESI-MS, pH-potentiometry, EXAFS and DFT calculations. Highlights of the scientific results are the followings: mechanisms suggestion for the chemical exchange between the Al(edta)- enantiomers; determination of the stability constants and structure of a dimer complex in Al(III)-ethylenediamine-N,N?-bis(3-hydroxy-2-propionate) (EDBHP), and the mononuclear AlH(2)L(2+), Al(H(2)L)(HL), Al(HL)(2)(-) and Al(HL)L(2-), dimeric Al(2)(HL)L(+) and trinuclear Al(3)H(5)L(4)(2+) complexes in Al(III)-N-phosponomethyl glycine (PMG/H(3)L) system; measuring the extreme stability of Tl(III)DOTA; preparation and characterisation of new Pt-Tl bonded complexes, (CN)5Pt-Tl(amine-polycarboxylate) and (CN)4Pt-Tl(dmso)5+, in water and dmso, respectively; photochemical study of (CN)5Pt-Tl-Pt(CN)53-; description of V(V)-peroxide system in ionic liquid

Interaction of anticancer reduced Schiff base coumarin derivatives with human serum albumin investigated by fluorescence quenching and molecular modeling

The specific binding of five reduced Schiff base derived 7-amino-coumarin compounds with antitumor activity to human serum albumin, the principal binding protein of blood, was studied by fluorescence spectroscopy. Their conditional binding constants were computed and the reversible binding at the Sudlow’s site I was found to be strong (KD ~ 0.03-2.09 M). Based on the data albumin can provide a depot for the compounds and is responsible for their biodistribution and transport processes. The experimental data is complemented by protein– ligand docking calculations for two representatives which support the observations. The proton dissociation constants of the compounds were also determined by UV-Vis spectrophotometric and fluorometric titrations to obtain the actual charges and distribution of the species in the various protonation states at physiological pH

A minimalist chemical model of matrix metalloproteinases- Can small peptides mimic the more rigid metal binding sites of proteins?

In order to develop a minimalist chemical model of matrix metalloproteinases (MMPs), we synthesized a pentadecapeptide (Ac-KAHEFGHSLGLDHSK-NH2) corresponding to the catalytic zinc(II) binding site of human MMP-13. The multi-domain structural organization of MMPs fundamentally determines their metal binding affinity, catalytic activity and selectivity. Our potentiometric, UV-VIS, CD, EPR, NMR, ESI-MS and kinetic study are aimed to explore the usefulness of flexible peptides to mimic the more rigid metal binding sites of proteins, to examine the intrinsic metal binding properties of this naked sequence, as well as to contribute the development of a minimalist, peptide-based chemical model of MMPs, including the catalytic properties. Since multiimidazole environment is also characteristic for copper(II), and recently copper(II) containing variants of MMPs have been identified, we also studied the copper(II) complexes of the above peptide. Around pH 6-7 the peptide, similarly to MMPs, offers {3Nim} coordinated binding site for both zinc(II) and copper(II). In the case of copper(II), the formation of amide coordinated species at higher pH ceased the analogy with the copper(II) containing MMP variant. On the other hand, the zinc(II)-peptide system mimics some basic features of the MMP active sites: the main species around pH 7 (ZnH2L) possesses {3Nim,H2O} coordination environment, the deprotonation of the zinc-bound water takes place near to the physiological pH, it forms relatively stable ternary complexes with hydroxamic acids, and the species ZnH2L(OH) and ZnH2L(OH)2 have notable hydrolytic activity between pH 7-9

Solution Equilibria of Anticancer Ruthenium(II)-(η6-p-Cymene)-Hydroxy(thio)pyr(id)one Complexes: Impact of Sulfur vs. Oxygen Donor Systems on the Speciation and Bioactivity

Stoichiometry and stability of antitumor ruthenium(II)-eta(6)-p-cymene complexes of bidentate (0,0) hydroxypyrone and (O,S) hydroxythiopyr(id)one type ligands were determined by pH-potentiometry, H-1 NMR spectroscopy and UV-Vis spectrophotometry in aqueous solution and in dependence of chloride ion concentration. Formation of mono-ligand complexes with moderate stability was found in the case of the hydroxypyrone ligands (ethyl maltol and allomaltol) predominating at the physiological pH range. These complexes decompose to the dinuclear tri-hydroxido bridged species [(Ru-II(eta(6)-p-cymene)h(OH)(3)](+) and to the metal-free ligand at basic pH values. In addition, formation of a hydroxido [Ru-II(eta(6)-p-cymene)(L)(OH)] species was found. The hydroxythiopyr(id)one ligands (thiomaltol, thioallomaltol, 3-hydroxy-1,2-dimethyl-thiopyridone) form complexes of significantly higher stability compared with the hydroxypyrones; their complexes are biologically more active, the simultaneous bi- and monodentate coordination of the ligands in the bis complexes (ML2 and ML2H) was also demonstrated. In the case of thiomaltol, formation of tris complexes is also likely at high pH. The replacement of the chlorido by the aqua ligand in the [Ru-II(eta(6)-p-cymene)(L)(CI)] species was monitored, which is an important activation step in the course of the mode of action of the complexes, facilitating binding to biological targets