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Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

January 2019 issue

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Cover illustration: The formation of a co-crystal involving 2,2'-dithiodibenzoic acid and benzoic acid is demonstrated through energy framework calculations, in which the interactions within the crystal packing are quantified in terms of energy. It is shown that the crystal is mainly directed by electrostatic forces owing to the presence of strong O-H...O hydrogen bonds that lead to a directional packing topology. The study is of importance in understanding the fundamental underlying principals of crystal packing and formation for the better design of physicochemical properties such as the mechanical strength of a crystal. See: Tan & Tiekink [Acta Cryst. (2019). E75, 1-7].

research communications


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The asymmetric unit of the title 1:2 co-crystal has a half mol­ecule of twofold symmetric di­thiodi­benzoic acid and a full mol­ecule of benzoic acid. These are connected into three-mol­ecule aggregates via hy­droxy-O—H⋯O(hy­droxy) hydrogen bonds.

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A second polymorph of 3-meth­oxy­benzoic acid with Z′ = 1 is reported and compared with first polymorph with Z′ = 2.


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In the crystal, the 1-decyl chains are in a `fully extended' conformation and inter­calate in the crystal packing to form hydro­phobic bands. The packing is further organized by π–π-stacking and C=O⋯π-ring inter­actions. The inter­molecular inter­actions were investigating by Hirshfeld surface analysis.

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The crystal structure of Ca2Te3O8 is isotypic with Pb2Te3O8.

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Sr2PdO3 adopts the Sr2CuO3 structure type. In comparison with previous determinations, the present redetermination results in improved precision of the structural parameters.

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In the title compound, the seven-membered diazepine ring adopts a boat-shaped conformation. In the crystal, mol­ecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers with an R_{2}^{2}(8) ring motif.

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The crystal structures of four di­meth­oxy­benzaldehyde (C9H10O3) isomers are reported and compared to the previously reported crystal structures of 3,4-di­meth­oxy­benzaldehyde and 2,6-di­meth­oxy­benzaldehyde. All di­meth­oxy­benzaldehyde mol­ecules in the crystal structure are nearly planar.

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The imidazo[4,5-b]pyridine unit is planar, while the phenyl and allyl substituents are rotated a little out of this plane. In the crystal, mol­ecules are linked via pairs of the weak inter­molecular C—H⋯N hydrogen bonds, forming inversion dimers with R_{2}^{2}(20) ring motifs. The dimers are further connected by π–π stacking inter­actions between the imidazo[4,5-b]pyridine ring systems.

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A new monoclinic polymorph of 2,2′-methyl­enebis(isoindoline-1,3-dione) with Z′ = 1 is reported.

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The mol­ecular structure of the title chalcone derivative is nearly planar and the mol­ecule adopts a trans-configuration with respect to the conjugated C=C double bond. In the crystal, the mol­ecules are connected by weak inter­molecular C—H⋯O and C—H⋯F hydrogen bonds into sheets parallel to (104). Weak inter­molecular π–π inter­actions also occur.

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The title halogenated organic chalcone was prepared by a Claisen–Schmidt condensation reaction. A Hirshfeld surface analysis was carried out to reveal the percentage contributions of the inter­molecular inter­actions. A theoretical study was performed using the density functional theory (DFT) at B3LYP with the 6–311 G++(d,p) basis set level to compare with the experimental results of the X-ray analysis and UV–vis absorption analysis in term of the geometrical parameters, HOMO-LUMO energy gap and charge distributions.

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The title lanthanide complex is isostructural with its La, Gd, Yb and Lu analogues. The Er3+ ion, located on a threefold rotation axis, is nine-coordinated in a distorted tricapped trigonal–prismatic geometry, which is completed by six oxygen atoms from three dhbq2− ligands and three oxygen atoms from coordinated water mol­ecules. Each dhbq2− ligand acts as a μ2-bis­(bidentate) bridging mode to connect two Er3+ ions to form honeycomb (6,3) two-dimensional sheets extending in the ab plane.

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Reaction of lomefloxacin [(RS)-4-(3-carb­oxy-1-ethyl-6,8-di­fluoro-4-oxo-1,4-di­hydro­quinolin-7-yl)-2-methyl­piperazine, Lf] with 5-fluoro­isophthalic acid leads to a charge-assistant hydrogen-bonding network between HLf+ cations and 3-carb­oxy-5-fluoro­benzoate anions.

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In the title compound the indazole portion is planar and the nitro group and the pendant phenyl ring are coplanar within 7°. Oblique stacks along the a-axis direction are formed by π–π-stacking inter­actions between the indazole unit and the pendant phenyl rings of adjacent mol­ecules. The stacks are linked into pairs through C—H⋯O hydrogen bonds.

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The syntheses and crystal structures of two PCN pincer iridium complexes, prepared from the reaction of their respective PCP pincer carbodi­phospho­rane iridium precursors with an organic azide, are reported. Crystal data for one of the precursors is also discussed.

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In the crystal, the mol­ecules are linked by N—H⋯O hydrogen bonds into supra­molecular chains propagating along the [101] direction.

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In the crystal structure, inter­molecular N—H⋯N hydrogen bonds link the mol­ecules into infinite ribbons extending along the [100] direction.

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In 2,3-di(thio­phen-2-yl)pyrido[2,3-b]pyrazine the thienyl rings are inclined to the mean plane of the pyrido­pyrazine moiety by 6.16 (7) and 86.66 (8)°, where as in the bromo derivative, 7-bromo-2,3-bis­(thio­phen-2-yl)pyrido[2,3-b] pyrazine, the corresponding dihedral angles are 33.29 (11) and 19.84 (9)°.

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In the title compound, the pendant di­hydro­pyran ring is rotationally disordered in a 90.899 (3):0.101 (3) ratio with the orientation of each component largely determined by intra­molecular N—H⋯O hydrogen bonds. In the crystal, inversion-related mol­ecules form dimers through inter­molecular N—H⋯O hydrogen bonds with the dimers associated along the b-axis direction by slipped π-stacking inter­actions between the pyridyl and di­hydro­pyran rings.

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The title compound, an example of a stable 1,2-naphtho­quinone, illustrates steric buttressing of the adamantanyl group.

Research communications

Research communications are designed to help authors bring out the science behind their structure determinations. Authors are encouraged to report more than one structure in the same communication and also to include the results of investigations with other techniques. The Research communications format makes Acta E the natural home for structure determinations with interesting science to report.

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Acta E is included in the Emerging Sources Citation Index.

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