Dichlorido[2-(3,5-dimethyl-1H-pyrazol-1-yl-κN 2)ethanamine-κN]zinc(II)

The amine title complex, [ZnCl2(C7H13N3)], resulted from imine hydrolysis in a Schiff base compound. The Zn metal atom has a distorted tetra­hedral geometry with the most significant deviation identified in the magnitude of the N—Zn—N angle. This deviation stems from the participation of the Zn and N atoms in a six-membered metallocyclic ring. The latter is in an approximate screw-boat conformation. Two strong N—H⋯Cl hydrogen bonds link the mol­ecules into ribbons propagating along the b-axis direction. The ribbons contain two second-order hydrogen-bonded motifs: a chain and a ring. The chain described by the graph set notation C 2 2(6) is formed by one hydrogen bond going in the forward direction (donor to acceptor) and the other in the backward direction (acceptor to donor). In the ring motif R 2 2(8), both hydrogen bonds propagate in the forward direction

Bis(2-hy­droxy­ethanaminium) tetra­chloridopalladate(II)

In the title compound, (C2H8NO)2[PdCl4], 2-hy­droxy­ethanaminium cations and tetra­chloridopalladate(II) dianions crystallize in a 2:1 ratio with the anion residing on a crystallographic inversion center. The cations and anions are linked in a complex three-dimensional framework by three types of strong hydrogen bonds (N—H⋯O, N—H⋯Cl, and O—H⋯Cl), which form various ring and chain patterns of up to the ternary graph-set level

Fémkomplexek mint enzimmodellek és biológiailag aktív vegyületek = Metal Complexes as Enzyme Models and Biologically Active Materials

A szerves vegyületek reakciói dioxigénnel mind biológiai mind pedig ipari szempotból fontos területe a kémiának. A biológiai rendszerek enyhe reakciókörülmények mellett működnek és működésük részletes megismerése és esetleges ipari alkalmazása állandó érdeklődésre tart számot. Kutatási projektünk metalloenzimek működési és szerkezeti modelljeinek a tanulmányozására irányult. Meg kívántuk ismerni, ki akartuk deríteni, hogy a triplet dioxigén milyen módokon aktiválható, és oxidázok, monooxigenázok, dioxigenázok, katalázok és szuperoxid dizmutázok hogyan működnek és mi az enzimreakciók feltételezett mechanizmusa. Nagy kihívás volt a C?H és C?C kötések aktiválása enyhe reakciókörülmények mellett, ahol jó részeredményeket értünk el. Megállapítottuk továbbá, hogy az u.n. reaktív oxigén molekulák (ROS) hogyan eliminálhatók a kémiai sztressz redukálása céljából, és tisztáztuk alapvető kémiájukat. Eredményeket értünk el un. ?bioinspirált? reakciók megvalósításában is és néhány mesterséges metalloenzim mint pl. kataláz és szuperoxid dizmutáz kidlgozásában. Eredményeinkről eddig 32 közlemény jelent meg nemzetközi szakfolyóiratokban. | The reaction of organic molecules with triplet dioxygen is very important both in biological and in industrial area. Biological systems work at much milder condition and there is a permanent interest to know how biological catalysts (enzymes) really work and how we can use them in chemistry. Our project focused on metalloenzyme models having either structural or functional similarities to the enzymes in order to find out the ways dioxygen can be activated, how oxidases, monooxygenases, dioxygenases, catalases, and superoxide dismutases really work and what is their possible mechanisms. Real challenges are the activation of C?H and C?C bonds under mild condition where we could find some progress. We obtained knowledge how ROS (Reactive Oxygen Species) formed during these processes can be eliminated to avoid oxidative stress and what is their basic chemistry. On the other hand we also had some progress in terms of ?bioinspired reactions? and also to find some artificial metalloenzymes such as catalase and superoxide dismutase. We published our results in 32 peer-reviewed international journals

Minimal Non-C-Perfect Hypergraphs with Circular Symmetry

In this research paper, we study 3-uniform hypergraphs H=(X,E) with circular symmetry. Two parameters are considered: the largest size α(H) of a set S⊂X not containing any edge E∈E, and the maximum number χ¯(H) of colors in a vertex coloring of H such that each E∈E contains two vertices of the same color. The problem considered here is to characterize those H in which the equality χ¯(H′)=α(H′) holds for every induced subhypergraph H′=(X′,E′) of H. A well-known objection against χ¯(H′)=α(H′) is where ∩E∈E′E=1, termed “monostar”. Steps toward a solution to this approach is to investigate the properties of monostar-free structures. All such H are completely identified up to 16 vertices, with the aid of a computer. Most of them can be shown to satisfy χ¯(H)=α(H), and the few exceptions contain one or both of two specific induced subhypergraphs H5⥁, H6⥁ on five and six vertices, respectively, both with χ¯=2 and α=3. Furthermore, a general conjecture is raised for hypergraphs of prime orders