Category: Selected publications

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

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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

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 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

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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 …

Vanadium(IV/V) complexes of Triapine and related thiosemicarbazones: Synthesis, solution equilibrium and bioactivity

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Kowol CR, Nagy NV, Jakusch T, Roller A, Heffeter P, Keppler BK, Enyedy ÉA Journal of Inorganic Biochemistry 152 (2015) 62–73 Abstract The stoichiometry and thermodynamic stability of vanadium(IV/V) complexes of Triapine and two related α(N)-heterocyclic thiosemicarbazones (TSCs) with potential antitumor activity have been determined by pH-potentiometry, EPR and 51V NMR spectroscopy in 30% (w/w) dimethyl sulfoxide/water solvent mixtures. In all cases, mono-ligand complexes in different protonation states were identified. Dimethylation of the terminal amino group resulted in the formation of Read More …

Fine tuning of crystal architecture by intermolecular interactions: synthon engineering

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Petra Bombicz, Tobias Gruber, Conrad Fischer, Edwin Weber, Alajos Kálmán CrystEngComm, 16 (18), 3646 – 3654, 2014 Abstract There has been a long time effort to influence or favourably fine tune structural properties by introduction of substituents or guest molecules of different sizes, shapes and chemical composition to consequently alter physico-chemical properties of the respective crystals. These attempts require the recognition, understanding and application of intermolecular interactions, crystallographic and, in case of occurrence, non-crystallographic symmetries. It brings us to the Read More …