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Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296

September 2019 issue

Highlighted illustration

Cover illustration: The culprit is the [sigma]-hole: short I...N halogen bonds do not necessarily come with high electron density in their (3,-1) critical point. The I-C geometry and Raman spectroscopy complement information from electron density. See Wang, George, Potts, Kremer, Dronskowski & Englert [Acta Cryst. (2019), C75, 1190-1201].

scientific commentaries


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There is an urgent need to improve our charge–density modelling capabilities for heavy atoms. A recent article opens up new opportunities in the charge–density and crystal engineering fields and in the overlap region between these fields.

feature articles


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The culprit is the σ-hole: short I⋯N halogen bonds do not necessarily come with high electron density in their (3,−1) critical point. The I—C geometry and Raman spectroscopy complement information from electron density.

research papers


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The crystal structure of a new quantum memory-storage material, scandium yttrium oxyorthosilicate, was analyzed using single-crystal X-ray diffraction. A comparative analysis was made of the polyhedral distortion parameters and distribution features of the cations in the RE lattice sites in the mixed silicates RE12–xRE2xSiO5 (RE = Sc, Y, Lu or Tm).

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Tetra­hydro­tetra­zoles are rare five-membered ring heterocycles containing four contiguous saturated N atoms. We have confirmed the assigned structure of a previously reported tetra­hydro­tetra­zole via X-ray crystallography.

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Phenytoin sodium crystallizes as a threefold modulated crystal structure that consists of a supercell made up of three close-to-identical repeat units.

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A new mononuclear europium com­plex incorporating the (+)-di-p-toluoyl-D-tartaric acid (D-H2DTTA) ligand, [Eu(HDTTA)3(CH3OH)3]n, has been synthesized and characterized. Circular dichroism spectra confirmed the chirality. The complex exhibits the characteristic red emission bands associated with the Eu3+ ion (CIE 0.63, 0.32), with a reasonably long lifetime of 0.394 ms, indicating effective energy transfer from the ligand to the metal centre.

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A cyclic carb­oxy­lic acid dimer with disordered O—(1 \over 2H)⋯(1 \over 2H)—O hydrogen bonds is observed in the crystal structure of N-tosyl-L-proline benzene hemisolvate. An analysis of the Cambridge Structural Database revealed that only six crystal structures with a similarly disordered cyclic dimer have been recognized previously.

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A novel stibium phosphate, LiBa(SbO)2(PO4)3, featuring an [(SbO)2(PO4)3] three-dimensional open framework, can be used as a luminescent host lattice and emits green light after doping with Tb3+ ions.

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A sulfur coordination polymer constructed from Zn2+ ions and 5-methyl­sulfanyl-1,3,4-thia­diazole-2-thione possesses high thermal and chemical stability and a linear temperature dependence of the bandgap from room temperature to 270 °C. Further investigation revealed that the bandgap changes sharply in ammonia, but only fluctuates slightly in other solvents, indicating its promising application as a selective sensor.

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A drug–drug anhydrous salt containing tolbutamide and metformin was created based on drug combinations for type 2 diabetes. Pharmaceutical property alterations were associated with the crystal packing features and potential hydrogen-bonding sites through observed changes in the crystal structures.

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The crystal structures of low-valent niobium isocyanide com­plexes are reported. The reaction of Nb(mesitylene)2 with 2,6-di­methyl­phenyl isocyanide resulted in a coupling of four isocyanide ligands, two per Nb atom, to produce dimers of the general formula [Nb(CNR)n]2[μ-C4(NR)4] (n = 4, 5), where the bridging ligand is a nitro­gen (NR) analog of the squarate dianion, (C4O4)2−. The reaction with the bulkier isocyanide ligand 2,6-diiso­propyl­phenyl isocyanide resulted in Nb(CNR)6, a rare paramagnetic monomer of formally Nb0.

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The disordered crystal structure of tri­phenyl­methanol features tetra­hedral chiral clusters formed through weak hydrogen bonds, leading to the formation of three-dimensional supra­molecular motifs having left or right handedness.

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A new phenyl­borate derivative of a Schiff base bridged phenolic di­phenyl­amine anti­oxidant was prepared by a facile synthesis method and characterized by single-crystal X-ray diffraction. Thermogravimetric analysis and anti­oxidant activity in vegetable-based lubricant oil were studied.

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A new lanthanum coordination polymer was prepared by employing a semi-rigid multidentate carb­oxy­lic acid ligand. It possesses (3,6)-connected two-dimensional kgd topology sheets consistsing of secondary building units of La2 clusters and 4,4′,4′′-{[(2,4,6-tri­methyl­benzene-1,3,5-tri­yl)tris­(methyl­ene)]tris­(­oxy)}tribenzoate ligands, which further stack into three-dimensional supra­molecular networks through π–π inter­actions.

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Three new ZnII CPs from 1D→3D with unique highly connected topologies were obtained by regulation of the flexible –CH2–O– linker of the 5-(4-carb­oxy­benz­yloxy)isophthalic acid ligand and subtle changes of the solvent, pH and auxiliary ligands. One com­plex shows high selectivity and sensitivity for detecting hexa­valent chromate anions in aqueous solution, with a very low limit of detection of 0.434 µM for the Cr2O72− ion.

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The structures of a new hybrid terpyridine–pyrazine ligand, 4′-[4-(pyrazin-2-yl)phen­yl]-4,2′:6′,4′′-terpyridine (L2), and its one-dimensional coordination polymer, [Zn(acac)2(L2)]n (acac is acetyl­acetonate), are reported. A complete picture of the inter­molecular inter­action landscape revealed some subtle details, for example, that some weak (at first sight negligible) C—H⋯N inter­actions in the structure of free L2 play a relevant role in the crystal stabilization.

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The crystal structures of SeP(o-tol)R2, where R is phenyl or cyclo­hexyl and o-tol is ortho-tolyl, are discussed, and their electronic and steric properties evaluated using various methods.

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Through systematic variation of the heteroatom and position of the carboxyl group on 1,3-azole­carb­oxy­lic acids, their influence on supra­molecular assembly is presented through nonbonding inter­actions and Hirshfeld surface analysis.

Special and virtual issues

Acta Crystallographica Section C has recently published special issues on

NMR Crystallography (March 2017)

Scorpionates: a golden anniversary (November 2016)

Full details are available on the special issues page.

The latest virtual issue features Coordination polymers, with an introduction by Len Barbour.

What are the 'most read' articles from the recent special issues?

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