Michał Wera

3-Hy-droxy-2-(4-hy-droxy-phen-yl)-4H-chromen-4-one.

In the title compound, C15H10O4, the benzene ring is twisted at an angle of 20.7 (1)° relative to the 4H-chromene skeleton. In the crystal, adjacent molecules are linked via a network of O—H⋯O and C—H⋯O hydrogen bonds. The mean planes of adjacent 4H-chromene moieties are parallel or oriented at an angle of 20.9 (1)° in the crystal structure.

2-(4-Hy-droxy-phen-yl)-3-meth-oxy-4H-chromen-4-one.

In the title compound, C16H12O4, the substituent benzene ring and methoxy group are twisted relative to the 4H-chromene skeleton by 24.1 (1) and 61.3 (1)°, respectively. In the crystal, molecules are connected by classical O—H⋯O and weak C—H⋯O hydrogen bonds, forming chains parallel to [201]. The 4H-chromene ring systems of adjacent molecules are either parallel or inclined at an angle of 28.9 (1)°.

2-(4-Fluoro-phen-yl)-3-hy-droxy-4H-chromen-4-one.

In the crystal structure of the title compound, C15H9FO3, inversely oriented molecules form inversion dimers through pairs of O—H⋯O hydrogen bonds. The benzene ring is twisted at an angle of 12.0 (1)° relative to the 4H-chromene skeleton of the molecule. Adjacent 4H-chromene units are parallel in a given column or oriented at an angle of 50.0 (1)° in neighboring, inversely oriented, columns, forming a herringbone pattern.

Structure, tautomerism, and features of 1-(5-acetyl-2,4-dihydroxyphenyl)-3-(furan-2-yl)prop-2-en-1-one (FC) and 1,1′-(4,6-dihydroxybenzene-1,3-diyl)bis[3-(furan-2-yl)prop-2-en-1-one] (FDC)

Quantum chemistry studies of various tautomeric/rotameric forms of the furanyl analogues of acetyl dihydroxychalcone (FC) and dihydroxydichalcone (FDC) have shown that the thermodynamically most stable molecules are planar. In the crystalline solid phase, both molecules are more (FDC) or less (FC) non-planar. Two relatively strong intramolecular H-bonds, whose existence is evidenced by X-ray, computational, and spectral investigations, stabilize the planar geometry and influence the features of the lowest energy tautomers/rotamers of both compounds. Extending to the visible region, the electronic absorption of FC and FDC is accompanied by an intramolecular electron density shift, a property that could have analytical implications.

3-Hy-droxy-2-(4-meth-oxy-phen-yl)-4H-chromen-4-one.

In the title compound, C16H12O4, the benzene ring is twisted at an angle of 12.3 (1)° relative to the 4H-chromene skeleton, and an intramolecular O—H⋯O hydrogen bond occurs. The methoxy group is almost coplanar with the benzene ring [1.5 (1)°]. In the crystal, inversely oriented molecules are arranged in double (A, A′) columns, along the b axis, and are linked by a network of intermolecular O—H⋯O hydrogen bonds (between A and A′) and C—H⋯π contacts (within A or A′). The 4H-chromene cores are parallel within A or A′, but make a dihedral angle of 88.6 (1)° between A and A′.

4-Meth-oxy-N-phenyl-aniline.

In the molecule of the title compound, C13H13NO, the two benzene rings are oriented at a dihedral angle of 59.9 (2)°. In the crystal structure, the benzene rings of neighbouring molecules are oriented nearly parallel or perpendicular, making dihedral angles of 2.8 (2) and 79.5 (2)°, respectively. The crystal structure is stabilized by a network of C—H⋯π and N—H⋯π interactions.

2-(4-Fluoro-phen-yl)-2H-chromen-4(3H)-one.

In the crystal structure of the title compound, C15H11FO2, molecules form inversion dimers through pairs of weak C—H⋯O hydrogen bonds. Dimers oriented in parallel, linked by C—H⋯π contacts, are arranged in columns along the b axis. The fluorophenyl ring and the benzene ring of the 2H-chromen-4(3H)-one unit are inclined to one another by 70.41 (16)°. They are respectively parallel in a given column or almost perpendicular [oriented at an angle of 87.8 (1)°] in neighbouring (inversely oriented) columns, forming a herringbone pattern.

{2-[1-(2-Amino-2-methyl­propyl­imino)eth­yl]phenolato-κ3N,N′,O}dioxidovanadium(V)

In the crystal structure of the title compound, [V(C12H17N2O)O2], the vanadium(V) centre is five-coordinate in a distorted square-pyramidal environment. The three atoms of the deprotonated Schiff base and a double-bonded O atom comprise the basal plane. N—H⋯O hydrogen bonds lead to a zigzag chain structure parallel to [001].

Structure, formation, thermodynamics and interactions in 9-carboxy-10-methylacridinium-based molecular systems

9-Carboxy-10-methylacridinium chloride and trifluoromethanesulfonate, the parent compounds for a wide range of chemiluminogenic salts of practical importance, were synthesized and thoroughly investigated to address problems concerning structural and thermodynamical issues of these cognitively interesting molecular systems. Under various conditions of crystallization, the title salts disclosed three types of crystals: one built from the monomeric form of cations and two containing homoconjugated cations. The title compounds made the first described derivatives of acridine, expressing homoconjugated cationic forms, both in crystalline solid and gaseous phases. The monocrystals were characterized, employing X-ray crystallography and spectroscopic methods such as MALDI-TOF MS, ESI-QTOF MS, NMR and UV-Vis. X-ray crystallography studies revealed the occurrence of the three different molecular architectures, in which not only the counter ions and stoichiometry are different, but also the space group and number of molecules in the unit cell. The energetics and intermolecular interactions occurring within the crystals were explored, applying crystal lattice energy calculations and Hirshfeld surface analysis. In order to elucidate the thermodynamics and origin of the experimentally revealed forms, computations based on the density functional theory were performed, assuming vapour and liquid phases.

Physicochemical characteristics of 2-, 3- and 4-methylpyridinium tetrachloroferrates(III)

AbstractThe crystal structure of 2-methylpyridinium tetrachloroferrate(III) was determined. The iron cation is tetracoordinated by chloride anions, and it adopts a slightly distorted tetrahedral coordination with three angles smaller, two almost equal and one larger than the tetrahedral. The compound is isostructural with its 3-, and 4-methylpyridinium analogues. The thermal properties of 2-, 3- and 4-methylpyridinium tetrachloroferrates(III) have been studied using TG and DSC techniques. The compounds exhibit a high stability in the melt.