Magdalena Małecka

Experimental and theoretical electron-density study of three isoindole derivatives: topological and Hirshfeld surface analysis of weak intermolecular interactions

A combined experimental and theoretical study of three isoindole derivatives was made on the basis of a topological analysis of their electron-density distributions. Experimental electron densities were determined from high-resolution X-ray diffraction data sets measured with synchrotron radiation at 100 K, whereas theoretical calculations were performed using DFT methods at the B3LYP\6-311++G(3df,3pd) level of approximation. Both experimental and theoretical models are in good agreement with each other. Since the analysed structures possess a variety of hydrogen-bonding interactions, weak intermolecular contacts of C-H···C(π), C,N(π)···C,N(π) and H···H types were subject to our special interest and are discussed in detail. They were characterized quantitatively and qualitatively by topological properties using Baders Atoms in Molecules theory and by mapping the electron-density distribution, electrostatic potential and a geometric function on the Hirshfeld surface. This way the forces and directions of intermolecular interactions as present on the molecular surfaces were depicted and described. These interactions not only guide crystal packing, but are likewise important for recognition processes involving (aza)isoindole fragments in a biological environment.

Electron density studies on hydrogen bonding in two chromone derivatives

The experimental electron densities of two chromone derivatives have been determined from X-ray synchrotron diffraction data at low temperature (100 K). Topological analysis of the electron density has been used to analyze the formation of resonance-assisted hydrogen bonds (RAHBs). Geometrical and topological parameters confirm π-electron delocalization within the hydrogen-bonded ring. In addition, weak C-H···O interactions were identified in both structures. Hydrogen-bond energies allowed medium and weak hydrogen bonds to be distinguished.

A structural framework of biologically active coumarin derivatives: crystal structure and Hirshfeld surface analysis

A series of three biologically active coumarin derivatives were synthesised and their crystal structures were determined by single X-ray analysis. The interactions between molecules were characterised using different synthons and via Hirshfeld surface analysis. The characteristic features of all structures are 2D sheets of molecules formed by C–H⋯O hydrogen bonds, which are enhanced by π⋯π interactions or C–H⋯O interactions. Additionally, the lipophilicity parameter (log P) which describes the compounds ability to go through membranes was compared with respect to different intermolecular interactions. It was found that higher lipophilicity is associated with a larger contribution of C–H⋯π interactions in the crystal packing.

Structure–cytotoxic activity relationship of 3-arylideneflavanone and chromanone (E,Z isomers) and 3-arylflavones

The E,Z-isomers of 3-arylidene substituted flavanone, chromanone and 3-aryl substituted flavone derivatives were tested in vitro for their cytotoxic activity against three cancer cell lines (HL-60, NALM-6, WM-115) and normal cell line (HUVEC). It was observed that substitution at C3 position led to significant enhance in cytotoxicity. Isomeric configuration of 3-arylideneflavanones had an influence on the cytotoxic potential. Multiple regression analysis combined with variable selection by genetic algorithm was used to model relationships between molecular descriptors and the cytotoxic activity. The most accurate QSAR models were based on a combination between energy of LUMO, experimental value of logP and partial charge on carbonyl oxygen (δO2).

Influence of selected inorganic counter-ions on the structure and antimicrobial properties of silver(I) complexes with imidazole-containing ligands

Water-soluble silver(I) complexes containing the 4(5)-(hydroxymethyl)imidazole ligand with the formula [Ag(4-CH2OHimH)2]X (where X = NO3−, ClO4−, CF3COO−, BF4− and SO3CH3−) were synthesized. The complexes were characterized by NMR (1H and 13C) and IR spectroscopy, ESI-MS spectrometry and EA. The molecular structures of three complexes were confirmed by X-ray crystallography. The antimicrobial activity of the silver(I) complexes were evaluated against six strains of microorganisms: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Proteus hauseri and Candida albicans. All tested silver complexes displayed excellent antibacterial properties against Gram-positive bacteria. Among them, the complex containing the trifluoroacetate counter-ion exhibited the highest antibacterial activity, with MIC values 2 to 3-fold lower than that required by silver sulfadiazine.

X-ray investigations of benzopyran derivatives substituted at position 3

The structures of two isomeric compounds, (E)-3-{[2-(dimethoxythiophosphoryl)-2-methylhydrazino]-methylidene}-3,4-dihydro-2H-1-benzopyran-2,4-dione, C 13 H 15 N 2 O 5 PS, and 3-{[2-(dimethoxythiophosphoryl)-2-methylhydrazino]carbonyl}-3,4-dihydro-4H-1-benzopyran-4-one, C 13 H 15 N 2 O 5 PS, have been determined from X-ray data and compared. The benzopyran moieties of both molecules are planar. Extra six-membered rings are formed by N-H...O hydrogen bonds. The geometry around the P atoms is tetrahedral, slightly deformed to trigonal pyramidal.

A benzopyran derivative substituted at position 3

In (E)-3-[[(diphenoxyphosphoryl)methylhydrazono]methyl]-4H-1-benzopyran-4-one, C(23)H(19)N(2)O(5)P, the benzopyran-methylhydrazone moiety is planar and the two phenoxy phenyl rings are inclined at angles of 21.29 (6) and 89.33 (5) degrees. Weak C[bond]H...O and C[bond]H...N intramolecular interactions exert some influence on the planarity and orientation of that moiety.

Investigations on benz­[1,2]­oxaphos­phinane derivatives

The structures of two compounds, 3-[1-(2-hydroxyethylamino)ethylidene]-2-methoxy-3,4-dihydro-1,2lambda(5)-benzoxaphosphinane-2,4-dione, C(13)H(16)NO(5)P, and 3-[1-(2-hydroxy-ethylamino)ethylidene]-2-methoxy-6-methyl-3,4-dihydro-1,2lambda(5)-benzoxaphosphinane-2,4-dione, C(14)H(18)NO(5)P, have been studied and compared. The oxophosphinane rings have a half-chair conformation and extra six- and five-membered rings are formed by intramolecular N-H...O hydrogen bonds. An intermolecular O-H...O hydrogen bond is also observed.

Single and double crown macrocyclic derivatives of cyclotriphosphazene as receptors of silver(I) ions

We report the preparation of new single and double PNP-lariat ether derivatives. L1 was synthesized from a MONO-ANSA precursor and L2 was synthesized from a BIS-ANSA precursor by subsequent substitution of the chlorine atoms. The reactive chlorine atoms were substituted by piperidinyl groups. Their structures were established by elemental analysis, MS, 1H NMR, 31P NMR and 13C NMR spectroscopy. Furthermore, this work includes an investigation of the complexation of silver(I) ions by the two new ligands in methanol and acetonitrile solutions. 1H NMR, 31P NMR and 13C NMR spectra were recorded to investigate how the complexation of silver(I) ions by the investigated macrocyclic ligands occurs.

Charge density distribution of 3‐(1‐aminoethylidene)‐2‐methoxy‐2‐oxo‐2,3‐dihydro‐2λ5‐benzo[e][1,2]oxaphosphinin‐4‐one

A combined experimental and theoretical study of one oxaphosphinane derivative was made on the basis of a topological analysis of its electron density distributions. The electron density was determined from a high-resolution X-ray diffraction data set measured with synchrotron radiation at 100 K, whereas theoretical calculations were performed using density functional theory (DFT) methods at the B3LYP\6-311++G(3df,3pd) level of approximation. The charge-density distribution and analysis of topological properties revealed that the P-O bond is of the transit closed-shell type. The crystal structure possesses one intra- and several intermolecular hydrogen bonds. They were characterized quantitatively by topological properties using Baders Atoms in Molecules theory. All hydrogen bonds were classified as weak. Further analysis of the experimental electron density by the source function allowed the intramolecular hydrogen bond to be characterized as an isolated hydrogen bond, in contrast to the resonance-assisted hydrogen bond in related molecules, such as chromone derivatives.