Two ammonium tetra­chlorido­aluminate salts: how a twinned ortho­rhom­bic structure emulates a trigonal crystal system

Tetra­butyl­ammonium tetra­chlorido­aluminate benzene hemisolvate crystallizes with discrete cations, anions and solvent mol­ecules, and the benzene mol­ecule is located on a centre of inversion. Tetra­ethyl­ammonium tetra­chlorido­aluminate also crystallizes with discrete cations and anions, and forms crystals which appear trigonal but are actually ortho­rhom­bic. With the additional reflections of the second and third domains of this nonmerohedral twin, a trigonal lattice is emulated, although the correct crystal system is ortho­rhom­bic.

Comparative structural analysis of 2,7-dieth­oxy-1,8-bis­(4-phen­oxy­benz­oyl)naphthalene and its homologues: orientation of the 4-phen­oxy­benzoyl groups at the 1- and 8-positions of the naphthalene ring

The title compound is analysed for comparison with the crystal structures of two homologues which have varying alk­oxy groups at the 2- and 7-positions of the naphthalene ring. Naphthalene analogues bearing 4-phen­oxy­benzoyl groups at the 1- and 8-positions of the naphthalene ring normally show C₂ symmetry affording anti conformers, but the formation of effective C—H⋯π inter­actions between 4-phen­oxy­benzoyl groups induces adoption of the syn conformer.

Two Zn^II mononuclear coordination compounds with pyridine­dicarboxyl­ate and auxiliary N-(pyridin-4-yl­methyl­idene)hydroxylamine ligands

In two new mononuclear mixed-ligand Zn^II complexes, the Zn^II cation of one is octa­hedrally coordinated by two chelating pyridine-2,5-di­carboxyl­ate ligands and by two water mol­ecules in a distorted octa­hedral geometry, while that of the second is coordinated by a tridentate pyridine-2,6-di­carboxyl­ate dianion and by two N-(pyridin-4-ylmethylidene)hydroxylamine mol­ecules in a distorted C₂-symmetric trigonal bipyramidal coordination geometry. [OK?]

A two-dimensional coordination polymer: poly[di­aqua­(μ₄-4,4′-oxy­dibenzo­ato)(μ₂-4,4′-oxy­dibenzo­ato)dilead(II)]

A lead(II) compound, prepared by the reaction of Pb(NO₃)₂ with 4,4′-oxybis(benzoic acid) in H₂O, possesses a 3,4-connected two-dimensional network with the point symbol {5³}₂{5⁴.8²}. The compound exhibits a fluorescence emission in the solid state at room temperature.

The effects of σ_C—Se–π hyper­conjugation in 1-meth­oxy- and 1-nitro-4-[(phenyl­selan­yl)meth­yl]benzene

The structures of 1-meth­oxy-4-[(phenyl­selan­yl)meth­yl]benzene and 1-nitro-4-[(phenyl­selan­yl)meth­yl]benzene differ in that the former contains an electron-rich aromatic ring and the latter contains an electron-deficient aromatic ring. Both adopt conformations which allow for σ_C—Se–π hyperconjugation, though the effects of this are not strong enough to be manifested in measurable differences in the structural parameters.

Two drimane lactones, valdiviolide and 11-epivaldiviolide, in the form of a 1:1 cocrystal obtained from Drimys winteri extracts

A cocrystal, obtained from Drimys winteri, is composed of two isomeric drimane sesquiterpene lactones, namely valdiviolide and 11-epivaldiviolide, neither of which has been reported in the crystal form. Both diastereoisomers present three chiral centres at sites 5, 10 and 11, with an SSR sequence in (Ia) and an SSS sequence in (Ib).

7-Cyclo­propyl-2′-de­oxy­tubercidin: a carbocyclic side-chain derivative of 7-de­aza-2′-de­oxy­adenosine

7-Cyclo­propyl-2′-de­oxy­tubercidin, a carbocyclic side-chain derivative of 7-de­aza-2′-de­oxy­adenosine, exhibits an anti glycosylic bond conformation.The furan­ose group shows a twisted C1′-exo sugar pucker (S-type), the orientation of the exocyclic C4′—C5′ bond is -ap (trans) and the cyclo­propyl substituent points away from the nucleobase (anti orientation). Within the three-dimensional extended crystal structure, the individual mol­ecules are stacked and arranged into layers, which are highly ordered and stabilized by hydrogen bonding.

4-(3-Aza­niumylprop­yl)morpholin-4-ium chloride hydrogen oxalate: an unusual example of a dication with different counter-anions

The mixed organic–inorganic salt 4-(3-aza­niumylprop­yl)morpholin-4-ium hydrogen oxalate forms an assembly of ionic components which are stabilized through a series of hydrogen bonds and charge-assisted inter­molecular inter­actions.

Structure determination of three furan-substituted benzimidazoles and calculation of π–π and C—H⋯π inter­action energies

The structures of 2-(furan-2-yl)-1-(furan-2-ylmeth­yl)-1H-benzimidazole, its hydro­chloride monohydrate, and the hydro­bromide salt of 5,6-dimethyl-2-(furan-2-yl)-1-(furan-2-ylmeth­yl)-1H-benzimidazole exhibit a combination of π–π and C—H⋯π inter­molecular inter­actions. DFT calculations were used to estimate the strength of these inter­actions.

Two complexes of Pt^IV and Au^III with 2,2′-di­pyridylamine and 2,2′-di­pyridyl­aminide ligands

The synthesis of two new Pt^IV and Au^III structures with 2,2′-dipyridylamine (Hdpa) and its anionic deprotonated derivative (dpa) are reported and compared. In the synthesis of the Au^III complex, an excess of Hdpa acts as a base, deprotonating the coordinating dipyridylamine.

A twofold inter­penetrating three-dimensional Cd^II coordination framework: poly[[μ₂-1,3-bis­(2-methyl-1H-imidazol-1-yl)benzene](μ₃-5-nitro­benzene-1,3-di­carboxyl­ato)cadmium(II)]

A cadmium(II) complex, prepared by reaction of Cd(NO₃)₂·6H₂O with 5-nitro­benzene-1,3-di­carb­oxy­lic acid and 1,3-bis­(2-methyl-1H-imidazol-1-yl)benzene in H₂O, possesses a twofold inter­penetrating 3,5-connected network with the {4².6⁵.8³}{4².6} topology. The compound exhibits fluorescence emissions in the solid state at room temperature.

Structural investigation of 5,10-A₂B₂-type porphyrins: palladium(II) and zinc(II) complexes of 5,10-di­bromo-15,20-bis­(4-methyl­phen­yl)porphyrin

A comparison of 5,10- and 5,15-di­bromo­porphyrins indicates differences in the contributions of individual macrocycle distortion modes.

Two new thio­phospho­ramide structures: N,N′,N′′-tri­cyclo­hexyl­phosphoro­thioic tri­amide and O,O′-di­ethyl (2-phenyl­hydrazin-1-yl)thio­phospho­nate

The P=S bond lengths, and the N⋯S distances in N—H⋯S=P hydrogen bonds are studied considering two new thio­phospho­ramide structures with P(S)[N]₃ and P(S)[O]₂[N] skeletons and their analogous compounds deposited in the Cambridge Structural Database.

High- and low-temperature phases in isostructural 4-chloro-3-nitro­aniline and 4-iodo-3-nitro­aniline

The second-order phase transition in 4-chloro-3-nitro­aniline and 4-iodo-3-nitro­aniline is characterized by the single-crystal X-ray structure determination of the respective isostructural phases as well as by Raman spectroscopy and differential scanning calorimetry.

Preparation and structural analysis of (±)-cis-ethyl 2-sulfanylidenedeca­hydro-1,6-naphthyridine-6-carboxyl­ate and (±)-trans-ethyl 2-oxo­octa­hydro-1H-pyrrolo­[3,2-c]pyridine-5-carboxyl­ate

Two new bicyclic mol­ecular scaffolds have been synthesized that represent privileged structural motifs for the design of bioactive ligands with potential for targeting, for example, G protein-coupled receptors. The important structural features of the two compounds are that one structure has two mol­ecules per asymmetric unit and the second structure is disordered over two possible positions.

The synthesis, crystal structure and magnetic properties of a one-dimensional terbium(III)–octa­cyanido­molybdate(V) assembly

A one-dimensional cyanide-bridged coordination polymer has been synthesized by the reaction of Tb(NO₃)₃·6H₂O with 3,4,7,8-tetra­methyl-1,10-phenanthroline (tmphen) and Cs₃[Mo(CN)₈]·4H₂O at room temperature. X-ray diffraction analysis reveals that the compound consists of one-dimensional chains in which [Tb(tmphen)₂(DMF)(H₂O)]³⁺ and [Mo^V(CN)₈]³⁻ units are linked in an alternating fashion through bridging cyanide ligands. Magnetic investigations show that ferromagnetic inter­actions exist in the compound.

An enanti­omerically pure P-stereogenic bis­phosphine: (S,S)-ethyl­ene­bis­[(2-methyl­phen­yl)phenyl­phosphine] (o-tolyl-DiPAMP)

The crystal structure of a homochiral P-stereogenic bis­phosphine has been determined and compared with its previously reported bis­phosphine oxide analogue.

A helical zinc(II) coordination polymer assembled from 1,3-bis­[(pyridin-3-yl)meth­oxy]benzene and benzene-1,4-di­carb­oxy­lic acid

In a one-dimensional Zn^II coordination polymer incorporating benzene-1,4-di­carboxyl­ate, aqua and 1,3-bis­[(pyridin-3-yl)meth­oxy]benzene ligands, (aqua)O—H⋯N hydrogen-bonding inter­actions induce the formation of one-dimensional helical chains which are inter­linked through (aqua)O—H⋯O hydrogen-bonding inter­actions, producing two-dimensional corrugated sheets.