Impact of copper and iron binding properties on the anticancer activity of 8-hydroxyquinoline derived Mannich bases

Veronika F. S. Pape, Nóra V. May, G. Tamás Gál, István Szatmári, Flóra Szeri, Ferenc Fülöp, Gergely Szakács* and Éva A. Enyedy* Dalton Trans., 2018, 47, 17032–17045 Abstract The anticancer activity of 8-hydroxyquinolines relies on complex formation with redox active copper and iron ions. Here we employ UV-visible spectrophotometry and EPR spectroscopy to compare proton dissociation and complex formation processes of the reference compound 8-hydroxyquinoline (Q-1) and three related Mannich bases to reveal possible correlations with biological activity. The studied Read More …

Polymorphism of a porous hydrogen bond assisted ionic organic framework

Dániel Vajk Horváth, Tamás Holczbauer,* Laura Bereczki, Roberta Palkó, Nóra Veronika May, Tibor Soós and Petra Bombicz  CrystEngComm (2018), accepted for publication The polymorphism of a porous, non-covalently bonded ionic organic framework is reported. The framework is constructed by hydrogen bonding and anion⋯π interactions. In a solvatomorphic lattice, pyridine takes part in the framework formation. The role of molecular rigidity in framework construction is proven by analogous non-porous crystals, where polymorphism also appears. Full text

Expanding the Pillararene Chemistry: Synthesis and Application of a 10 + 1 Functionalized Pillar[5]arene

Márton Bojtár, András Simon, Petra Bombicz, and István Bitter Organic Letters (2017)  19 (17), 4528–4531 A novel functionality was introduced in the pillararene family by the Claisen rearrangement of monoallyl pillar[5]arene. This new key derivative can lead to the formation of a 10 + 1 functionalized derivative, a useful scaffold for further derivatization. Except for the previously known monodeprotection reaction, all steps proceed efficiently with high yields and easy separation. In addition, a solvent-responsive pseudo[1]rotaxane was synthesized based on this novel functionality. Read More …

The way from isostructurality to polymorphy. Where are the borders? The role of supramolecular interactions and crystal symmetries.

Petra Bombicz Crystallography Reviews, 23(2), 118-151, 2017. ABSTRACT To produce substances with required physico-chemical properties demands the recognition of structural features of materials. It includes polymorphism and isostructurality which are strongly related with intermolecular interactions and crystal symmetries. Fine tuning of structural properties can be achieved by the application of substituents or in the case of multi-component systems by the introduction of molecules of different sizes, shapes and chemical compositions. How far can a crystal structure tolerate small molecular changes? Read More …

Exploring the boundaries of direct detection and characterization of labile isomers – a case study of copper(II)–dipeptide systems

Eszter Tóth, Nóra V. May, Antal Rockenbauer, Gábor Peintler and Béla Gyurcsik Dalton Trans., 2017,46, 8157-8166 ABSTRACT The investigation of the linkage isomers of biologically essential and kinetically labile metal complexes in aqueous solutions poses a challenge, as these microspecies cannot be separately studied. Therefore, derivatives are commonly used to initially determine the stability or spectral characteristics of at least one of the isomers. Here we directly detect the isomers, describe the metal ion coordination sphere, speciation and thermodynamic parameters by Read More …

Structural, analytical and DSC references to resolution of 2-Methoxy-2-phenylacetic Acid with Chiral 1-Cyclohexylethylamines through Gas-Antisolvent Precipitation

Amit D. Zodge, Petra Bombicz, Edit Székely, György Pokol, János Madarász Thermochimica Acta, 648, 23-31, (2017) ABSTRACT The system of intermolecular interactions is very similar in the solid state of the chiral and racemic α-methoxyphenylacetic acids (α-MPAA) indicated by both Differential Scanning Calorimetry (DSC)and FTIR-spectroscopy, and even proved by single crystal structure determination. It makes the resolution of such a racemate compound challenging even by supercritical fluid  xtraction. The chiral(S)-α-methoxyphenylacetic acid (1) crystallizes in orthorhombic crystal system (space group P212121,a Read More …

A novel 1,3,5-triaminocyclohexane-based tripodal ligand forms a unique tetra(pyrazolate)-bridged tricopper(II) core: solution equilibrium, structure and catecholase activity

Attila Szorcsik, Ferenc Matyuska, Attila Bényei, Nóra V. Nagy, Róbert K. Szilágyi and Tamás Gajda* Dalton Trans., 2016, 45, 14998-15012   ABSTRACT Copper(II) complexes of a polydentate tripodal ligand L × 3HCl (L = N,N’,N’’-tris(5-pyrazolylmethyl)-cis, cis-1,3,5-triaminocyclohexane) were characterized in both solution and solid states. Combined evaluation of potentiometric, UV-VIS, and EPR data indicated the formation of two mononuclear (CuHL, CuL) and three trinuclear (Cu3H−xL2, x = 2, 3, 4) complexes. The high stability and spectroscopic properties of the CuL species indicate Read More …

Symmetry-controlled rearrangements in Piedfort Units (PU) of 2,4,6-triaryloxy-1,3,5-triazines

Petra Bombicz, Nikoletta B. Báthori, Alajos Kálmán Struct. Chem., 26, 1611-1619, 2015   Abstract 2,4,6-triaryloxy-1,3,5-triazines (POT) form in general molecular diads, termed as Piedfort Units (PU), in their crystals and their clathrates. Their bulky phenyl substituents (R = Me, F, Cl, Br, I, CN) in ortho, meta or para position substantially hinder internal rotations. Instead, non-crystallographic rotations (ncr) or translations (nct) are the bridges between the semirigid homologues or analogues, occasionally polymorphs. They occur in the space groups R3c (161), Read More …

Strain-Driven Direct Cross-Aldol and -Ketol Reactions of Four-Membered Heterocyclic Ketones

 Zoltán Dobi, Tamás Holczbauer, and Tibor Soós* Org. Lett., 2015, 17 (11), pp 2634–2637 Abstract Owing to the ring strain and α-heteroatom effect, the four-membered heterocyclic ketones can undergo direct cross-aldol and -ketol reactions without the need for preformed enol or “enolate-like” intermediates. Besides the organocatalyzed cross-ketol addition onto their highly active carbonyl group, their ability to act as a nucleophilic donor has also been explored. As a result, a number of discrete aldol adducts were synthesized and the distinct reactivities were successfully combined into Read More …

Supramolecular Interactions in the Solid State

Giuseppe Resnati, Elena Boldyreva, Petra Bombicz, Masaki Kawano IUCrJ, 2, 675-690 (2015) Abstract In the last few decades, supramolecular chemistry has been at the forefront of chemical research, with the aim of understanding chemistry beyond the covalent bond. Since the long-range periodicity in crystals is a product of the directionally specific short-range intermolecular interactions that are responsible for molecular assembly, analysis of crystalline solids provides a primary means to investigate intermolecular interactions and recognition phenomena. This article discusses some areas Read More …