2‐[6‐(1H‐Benzimidazol‐2‐yl)‐2‐pyridyl]‐1H‐benzimidazol‐3‐ium perchlorate monohydrate

The title compound, C₁₉H₁₄N₅⁺·ClO₄^?·H₂O, contains planar C₁₉H₁₄N₅⁺ cations, perchlorate anions and water mol­ecules. The two closest parallel cations (plane‐to‐plane distance of 3.41 Å), together with two neighbouring perchlorate anions and two water mol­ecules, form an electrically neutral quasi‐dimeric unit. Two acidic H atoms of the cation, both H atoms of the water mol­ecule, the N atoms of the imidazole rings and three of the four O atoms of the perchlorate anion are involved in the hydrogen‐bonding network within the dimeric unit. The remaining third acidic H atom of the imidazole rings and the water mol­ecules complete a two‐dimensional network of hydrogen bonds, thus forming puckered layers of dimers. The angle between the planes of two neighbouring dimeric units in the same layer is 33.25 (3)°.     

Ethyl N‐[2‐(hydroxy­acetyl)­phenyl]­carbamate,ethyl N‐[2‐(hydroxy­acetyl)‐4‐iodo­phenyl]­carbamate and ethyl N‐[2‐(hydroxy­acetyl)‐4‐methyl­phenyl]­carbamate

In ethyl N‐[2‐(hydroxy­acetyl)phenyl]carbamate, C₁₁H₁₃NO₄, all of the non‐H atoms lie on a mirror plane in the space group Pnma; the mol­ecules are linked into simple chains by a single C—H⋯O hydrogen bond. The mol­ecules of ethyl N‐[2‐(hydroxy­acetyl)‐4‐iodo­phenyl]carbamate, C₁₁H₁₂INO₄, are linked into sheets by a combination of O—H⋯I and C—H⋯O hydrogen bonds and a dipolar I⋯O contact. Ethyl N‐­[2‐(hydroxy­acetyl)‐4‐methyl­phenyl]carbamate, C₁₂H₁₅NO₄, crystallizes with Z′ = 2 in the space group P; pairs of mol­ecules are weakly linked by an O—H⋯O hydrogen bond and these aggregates are linked into chains by two independent aromatic π–π stacking inter­actions.     

2‐(4‐Chloro­phenyl)‐1,3‐di­cyano‐6,7‐di­hydro‐4‐imino‐9,10‐di­methoxy­benzo­[a]­quinolizine–water (2/5)

Crystals of the title compound, C₂₃H₁₇ClN₄O₂·2.5H₂O, contain channels filled with highly disordered water mol­ecules. The best structure refinement was obtained by removing the solvent contribution from the intensity data and refining against a solvent‐free model. The central six‐membered ring of the quinolizine mol­ecule has a slightly distorted screw‐boat conformation.     

1‐[2‐(1‐Hydroxy­cyclo­hexyl)‐2‐(4‐methoxy­phenyl)­ethyl]­di­methyl­ammon­ium chloride (venlafaxine hydro­chloride)

The crystal structure of racemic Venlafaxine hydro­chloride, C₁₇H₂₈NO₂⁺·Cl^?, consists of two types of parallel chains formed by translated Venlafaxine⁺ cations, hydrogen bonded by Cl^? anions, and characterized by the opposite chirality of their constituent mol­ecules. These chains organize in two different types of broad layers of opposite handedness, related by a glide plane.     

3,5‐Di­amino‐6‐(2‐fluoro­phenyl)‐1,2,4‐triazine–di­methyl­form­amide (1/1)

The title compound, C₉H₈FN₅·C₃H₇NO, contains two independent complexes in the asymmetric unit, each consisting of one 3,5‐di­amino‐6‐(2‐fluoro­phenyl)‐1,2,4‐triazine mol­ecule and one di­methyl­form­amide solvent mol­ecule. One triazine mol­ecule is disordered over two conformations within the crystal, the occupancies being 62 (1) and 38 (1)%. The phenyl ring of this mol­ecule resolves into two conformations rotated by almost 180° about the bridging bond between the two rings, while the triazine rings approximately superimpose on each other. The triazine mol­ecules of the asymmetric unit differ in the dihedral angles between their respective phenyl and triazine ring planes, these being 57.6 (2)° for the fully occupied, and 76.9 (6) and 106.8 (8)° for the partially occupied mol­ecules. An extensive network of hydrogen bonds maintains the crystal structure.     

7‐Carboxyl­ato‐8‐hydroxy‐2‐methyl­quinolinium monohydrate and 7‐carboxy‐8‐hydroxy‐2‐methyl­quinolinium chloride monohydrate at 100 K

Both 7‐carboxyl­ato‐8‐hydroxy‐2‐methyl­quinolinium monohydrate, C₁₁H₉NO₃·H₂O, (I), and 7‐carboxy‐8‐hydroxy‐2‐methyl­quinolinium chloride monohydrate, C₁₁H₁₀NO₃⁺·Cl⁻·H₂O, (II), crystallize in the centrosymmetric P space group. Both compounds display an intramolecular O—H⋯O hydrogen bond involving the hydroxy group; this hydrogen bond is stronger in (I) due to its zwitterionic character [O⋯O = 2.4449 (11) Å in (I) and 2.5881 (12) Å in (II)]. In both crystal structures, the HN⁺ group participates in the stabilization of the structure via intermolecular hydrogen bonds with water mol­ecules [N⋯O = 2.7450 (12) Å in (I) and 2.8025 (14) Å in (II)]. In compound (II), a hydrogen‐bond network connects the Cl⁻ anion to the carboxylic acid group [Cl⋯O = 2.9641 (11) Å] and to two water mol­ecules [Cl⋯O = 3.1485 (10) and 3.2744 (10) Å].     

A synchrotron‐radiation study of the lactone form of rhodamine B at 120 K

The structure of the lactone form of rhod­amine B, 3,6‐bis­(diethyl­amino)‐1′,3′‐di­hydro­spiro­[xanthene‐9,3′‐isobenzo­furan]‐1′‐one, C₂₈H₃₀N₂O₃, has been determined at 120 K using synchrotron radiation at a wavelength of 0.496 Å. The structure contains two independent rhod­amine B mol­ecules with virtually identical geometry. The xanthene main planes of the mol­ecules are inclined at an angle of 41.6 (2)° to one another. Molecule 2 has a statistically disordered ethyl group, with 71% in one orientation and 29% in a second orientation. The lactone C—O bonds are 1.497 (1) and 1.495 (1) Å. There are no classical hydrogen bonds, but the structure is stabilized by two short C?O interactions. The crystals of the lactone form were produced by a novel hydro­thermal reaction.     

Two hydrates of 2,6‐bis­(1H‐benzimidazol‐2‐yl)­pyridine

The structures of the mono‐ and sesquihydrates of 2,6‐bis(1H‐benz­imi­da­zol‐2‐yl)­pyridine (bbip) are reported. Phase (I), C₁₉H₁₃N₅·H₂O, has one water and one bbip mol­ecule in the asymmetric unit, while phase (II), C₁₉H₁₃N₅·1.5H₂O, has three water mol­ecules and two bbip mol­ecules in the asymmetric unit. The compounds exhibit very similar molecular geom­etries but different packing organizations, which result from intricate hydrogen‐bonding schemes.     

N‐(3H‐Thia­zol‐2‐yl­idene)­nitr­amine and N‐methyl‐N‐(thia­zol‐2‐yl)­nitr­amine

The geometries of the thia­zole ring and the nitr­amino groups in N‐(3H‐thia­zol‐2‐yl­idene)­nitr­amine, C₃H₃N₃O₂S, (I), and N‐­methyl‐N‐(thia­zol‐2‐yl)­nitr­amine, C₄H₅N₃O₂S, (II), are very similar. The nitr­amine group in (II) is planar and twisted along the C—N bond with respect to the thia­zole ring. In both structures, the asymmetric unit includes two practically equal mol­ecules. In (I), the mol­ecules are arranged in layers connected to each other by N—H⋯N and much weaker C—H⋯O hydrogen bonds. In the crystal structure of (II), the mol­ecules are arranged in layers bound to each other by both weak C—H⋯O hydrogen bonds and S⋯O dipolar interactions.     

Hierarchy of hydrogen bonding in bis­(1,4,7‐trioxa‐10‐azoniacyclo­dodecane) bis­(4‐amino­benzoate) trihydrate

In the title compound, 2C₈H₁₈NO₃⁺·2C₇H₆NO₂⁻·3H₂O, proton transfer occurs from the carboxylic acid group of the 4‐amino­benzoic acid (PABA) mol­ecule to the amine group of the macrocycle, resulting in the formation of a salt‐like adduct. The anions are combined into helical chains which are further bound by the water mol­ecules into sheets. The macrocyclic cations are situated between these layers and are bound to the anions both directly and via bridging water mol­ecules. The structure exhibits a diverse system of hydrogen bonding.     

Chloro­bis­(thio­urea‐κS)copper(I) bis(4,5‐di­aza­fluoren‐9‐one) mono­hydrate

The title compound, [CuCl(CH₄N₂S)₂]·2C₁₁H₆N₂O·H₂O, consists of mol­ecules of a Cu^I–thio­urea complex, free 4,5‐di­aza­fluoren‐9‐one (dafone) and crystalline water. The planar complex mol­ecule has trigonal coordination geometry around the Cu^I atom. The dafone and water mol­ecules, which are hydrogen bonded to the Cu^I complex, are approximately coplanar with this complex. The crystal displays a sheet structure and π–π stacking is observed between neighbouring sheets.     

The antiestrogen [2‐(4‐benzyl­phenoxy)­ethyl]­diethyl­ammonium chloride

The crystal structure of the title compound, C₁₉H₂₆NO⁺·Cl^? (common name: N,N‐diethyl‐2‐[(4‐phenyl­methyl)phenoxy]‐ethan­amine hydro­chloride), contains one mol­ecule in the asymmetric unit. The planes through the two phenyl rings are roughly perpendicular. Protonation occurs at the N atom, to which the Cl^? ion is linked via an N—H?Cl hydrogen bond. The mol­ecule adopts an eclipsed rather than extended conformation.     

Dichloro­{2‐[2‐(dimethyl­ammonio)­ethyl­imino­meth­yl]‐4‐nitro­phenolato}­zinc(II) in unsolvated and hemihydrate forms

The two title complexes, [ZnCl₂(C₁₁H₁₅N₃O₃)], (I), and [ZnCl₂(C₁₁H₁₅N₃O₃)]·0.5H₂O, (II), are mononuclear zinc(II) compounds. In both structures, the Zn^II atom is four‐coordinated in a tetra­hedral configuration by one imine N atom and one phenolate O atom of a Schiff base, and by two Cl atoms. The structure of each of the two zinc(II) complex molecules of (II) is similar to that of (I). In (I), the mol­ecules are linked through inter­molecular hydrogen bonds, forming a three‐dimensional framework. In (II), the solvent water mol­ecules are linked to the zinc(II) moieties through inter­molecular O—H⋯O and O—H⋯Cl hydrogen bonds. The mol­ecules in (II) are further linked via other inter­molecular hydrogen bonds, forming a three‐dimensional framework.     

The perchlorate salt of the novel diprotonated dinucleating ligand 1,3‐bis­{[2‐(2‐pyridinio)eth­yl][2‐(2‐pyrid­yl)eth­yl]amino}benzene

In the title salt, 1,3‐bis­{[2‐(2‐pyridinio)eth­yl][2‐(2‐pyrid­yl)ethyl]amino}benzene diperchlorate dihydrate, C₃₄H₃₈N₆²⁺·2ClO₄⁻·2H₂O, the cation contains two ethyl­pyrid­yl and two ethyl­pyridinium pendant pairs anchored to the two N atoms of 1,3‐phenyl­enediamine. The pyrid­yl and pyridinium N atoms are flanked by a mol­ecule of water through strong hydrogen‐bonding inter­actions [N—H⋯O = 2.762 (6) and 2.758 (6) Å, and O—H⋯N = 2.834 (6) and 2.839 (6) Å]. The water mol­ecules have weak hydrogen‐bonding inter­actions with the perchlorate anions as well. One of the perchlorate anions is severely disordered.     

Cinnamolid‐3β‐ol hemihydrate and 3β‐hydroxycinnamolide acetate,two drimanolide‐class sesquiterpene lactones from Warburgia ugandensis

3β‐Hydr­oxy‐7‐drimen‐12,11‐olide hemihydrate, C₁₅H₂₂O₃·0.5H₂O, (I), has two sesquiterpene mol­ecules and one water mol­ecule in the asymmetric unit. The OH groups of both mol­ecules and both H atoms of the water mol­ecule are involved in near‐linear inter­molecular hydrogen bonds, having O⋯O distances in the range 2.632 (3)–2.791 (2) Å. 3β‐Acet­oxy‐7‐drimen‐12,11‐olide, C₁₇H₂₄O₄, (II), has its ring system in very nearly the same conformation as the two mol­ecules of (I).     

Aqua­(di‐2‐pyridylamine)oxalato­copper(II) monohydrate

In the structure of the title complex, [Cu(C₂O₄)(C₁₀H₉N₃)(H₂O)]·H₂O, the Cu^II atom displays a square‐pyramidal geometry, being coordinated by two N atoms from the di‐2‐pyridylamine ligand, two O atoms from the oxalate group and one O atom of a water mol­ecule. The complex mol­ecules are linked to form a three‐dimensional supra­molecular array by hydrogen‐bonding inter­actions between coordinated/uncoordinated water mol­ecules and the uncoordinated oxalate O atoms of neighboring mol­ecules.     

(μ‐2,6‐Bis{[(2‐hydroxy­phenyl)­(2‐pyri­dyl­methyl)­amino]­methyl}‐4‐methyl­phenolato)­bis­[di­aqua­nickel(II)] ace­tate dimethyl­formamide 0.75‐hy­drate

The binuclear cation of the title compound, [Ni₂(C₃₃H₂₉­N₄O₃)(H₂O)₄]C₂H₃O₂·C₃H₇NO·0.75H₂O, was synthesized as a model for the active site of urease. Two tridentate halves of the symmetrical 2,6‐bis{[(2‐hydroxy­phenyl)(2‐pyridyl­methyl)­amino]­methyl}‐4‐methyl­phenolate (BPPMP^3?) ligand are arranged in a meridional fashion around the two Ni^II ions, with the phenoxo O atom bridging the Ni^II ions. The cation has an approximate twofold rotation axis running through the C—O bond of the bridging phenolate group. Four water mol­ecules complete the octahedral environment of each Ni^II ion.     

1‐(2‐Hydroxy‐4,6‐di­methyl­phenyl)­ethanone

In the crystal of the title compound, C₁₀H₁₂O₂, there are two symmetry‐independent mol­ecules, which are essentially superimposable. Each mol­ecule exhibits an intramolecular O—H?O hydrogen bond, with O?O separations of 2.483 (4) and 2.468 (4) Å.     

N‐(4‐Cyano­phenyl)‐α‐(4‐methoxy­phenyl)­nitro­ne

In the crystal structure of the title compound, 4‐cyano‐N‐(4‐methoxy­benzyl­idene)­phenyl­amine N‐oxide, C₁₅H₁₂N₂O₂, the 4‐methoxy­phenyl is approximately coplanar with the nitrone moiety but significantly rotated with respect to the 4‐cyano­phenyl moiety. The extent of this rotation is significantly different for the two crystallographically independent mol­ecules of the asymmetric unit [dihedral angles of 19.4 (1) and 26.5 (1)°]. The geometry about the C=N bond is Z. The two mol­ecules are related to one another by a pseudo inversion centre.     

Redetermination of fac‐tris­(benzo­hydrox­am­ato)­iron(III) tri­hydrate

Due to its importance as a model for naturally occurring iron(III) siderophores such as desferriox­amine B, the crystal structure of the title compound, [Fe(C₇H₆NO₂)₃]·3H₂O, which was reported previously (R = 0.12, one of water mol­ecules disordered), has been redetermined (R = 0.041 without disorder). The complex has pseudo‐octahedral geometry around the Fe^III atom, with Fe—O bond lengths ranging from 1.9689 (18) to 2.0585 (17) Å and O—Fe—O bond angles in the chelate rings of 78.01 (7), 78.83 (7) and 78.95 (7)°. There is extensive hydrogen bonding involving the water mol­ecules and the hydro­xamate ligands.