FeII2(PO4)(OH), a synthetic analogue of wolfeite

This paper reports the hydrothermal synthesis and crystal structure refinement of diiron(II) phosphate hydroxide, Fe^II₂(PO₄)(OH), obtained at 1063 K and 2.5 GPa. This phosphate is the synthetic analogue of the mineral wolfeite, and has a crystal structure topologically identical to those of minerals of the triplite–triploidite group. The complex framework contains edge‐ and corner‐sharing FeO₄(OH) and FeO₄(OH)₂ polyhedra, linked via corner‐sharing to the PO₄ tetrahedra (average P—O distances are between 1.537 and 1.544 Å). Four five‐coordinated Fe sites are at the centers of distorted trigonal bipyramids (average Fe—O distances are between 2.070 and 2.105 Å), whereas the coordination environments of the remaining Fe sites are distorted octahedra (average Fe—O distances are between 2.146 and 2.180 Å). The Fe—O distances are similar to those observed in natural Mg‐rich wolfeite, except for two Fe—O bond distances, which are significantly longer in synthetic Fe²⁺₂(PO₄)(OH).     

A high‐pressure single‐crystal synchrotron diffraction study of NH4RbTe4O9·2H2O: stability of three different TeOx coordination polyhedra

The crystal structure of ammonium rubidium nonaoxotetratellurate(IV) dihydrate has been studied as a function of pressure up to 7.40 GPa. The ambient‐pressure structure is characterized by the co‐existence of three different Te—O polyhedra (TeO₃, TeO₄ and TeO₅), which are connected to form layers. NH₄⁺, H₂O and Rb⁺ are incorporated between the layers. Both the Rb1 position, which is located on a twofold axis, and the Rb2 position are partially occupied. The three different types of coordination polyhedra around Te⁴⁺ are stable up to at least 5.05 GPa. No phase transition is observed. The fit of the unit‐cell volume as a function of pressure gives a zero‐pressure bulk modulus of 34 (1) GPa with a zero‐pressure volume of V₀ = 2620 (4) ų [B′ = 1.4 (2)].     

Redetermination of bis[μ3‐1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositolato(3–)]tribismuth(III) trichloride hexahydrate

The crystal structure of the title compound, [Bi₃(C₆H₁₂N₃O₃)₂]Cl₃·6H₂O, which was described in the space group R3 [Hegetschweiler, Ghisletta & Gramlich (1993). Inorg. Chem. 32 , 2699–2704], has been redetermined in the revised space group R32 as suggested by Marsh [Acta Cryst. (2002), B 58 , 893–899]. Accordingly, the significant difference in the Bi—N bond distances of 2.43 (2) and 2.71 (1) Å, as noted in the previous study, proved to be an artifact. As a consequence, the [Bi₃(H₋₃taci)₂]Cl_6/3 entity (taci is 1,3,5‐triamino‐1,3,5‐trideoxy‐cis‐inositol) adopts D₃ symmetry and the three Bi atoms lie on C₂ axes with equal Bi—N bond distances of 2.636 (3) Å.     

The weakly coordinating perchlorate group in bis(N,N′‐dimethylethylenediamine‐κ2N,N′)bis(perchlorato‐κO)copper(II) studied at 100, 250 and 400 K

The crystal structure of the title compound, [Cu(ClO₄)₂(C₄H₁₂N₂)₂], (I), is reported at 100, 250 and 400 K. The Cu^II cation in this complex is coordinated in a distorted octahedral mode characteristic of Jahn–Teller systems. The coordination of the perchlorate ligands via longer, and presumably weaker, axial Cu—O distances varies significantly as a function of temperature. One of the Cu—O distances increases between 100 and 250 K, and one of the Cu—O—Cl angles expands between 250 and 400 K. At all temperatures, the complex forms a two‐dimensional N—H...O hydrogen‐bond network in the (001) plane.     

Crystal Structure of the High Pressure Phase(II) in CuGeO3

Crystal structures of the ambient pressure and temperature phase (phase I) and high pressure phase (phase II) in CuGeO₃ were studied by means of the high pressure single‐crystal X‐ray diffraction method in a diamond anvil cell using high power X‐ray generator and imaging plate detector. The pressure dependence of the atomic displacements in the phase I was investigated under the hydrostatic pressure of 0.1 MPa and 2.9 and 3.9 GPa. The lattice is particularly compressive in the b direction. In phase I the rippled layers are formed by the corner‐shared chains of GeO₄ tetrahedra and edge‐linked planar CuO₄. Major effects of pressure, directly related to the shortening of the b‐axis, consist of an enhanced folding of the rippled layers towards the b‐direction and of a shortening of the weak Cu–O bond. The crystal structure of phase II is monoclinic, a = 4.935(57), b = 6.754(14), c = 6.208(11) Å, β = 92.67(3)°, space group; P2₁/c. The transition from phase I to II involves a corrugated arrangement of the both cation with some oxygens around the c‐axis. Ge ion at the transition point of 6.4 GPa changes its coordination number from four‐fold to five‐fold, and Cu ion occupies a position of seven‐fold site. The structure of phase II is explained as a slab structure having unique edge‐ and corner‐sharing arrangements of GeO₅ and CuO₇ polyhedra. The average Ge–O and Cu–O distances in phase II is 1.92 and 2.17 Å, respectively, at 6.5 GPa.     

Tl2CO3 at 3.56 GPa

The crystal structure of thallium carbonate, Tl₂CO₃ (C2/m, Z = 4), is stable at least up to 3.56 GPa, as demonstrated by hydrostatic single‐crystal X‐ray diffraction measurements in a diamond anvil cell at room temperature. Our results contradict earlier observations from the literature, which found a structural phase transition for this compound at about 2 GPa. Under atmospheric conditions, all atoms except for one O atom reside on the mirror plane in the high‐pressure structure. The compression mainly affects the part of the structure where the nonbonded electron lone pairs on the Tl⁺ cations are located.     

(2‐Methyl­quinolin‐8‐olato)­iron(III) and ‐copper(II) complexes

The crystal structures of tris(2‐methyl­quinolin‐8‐olato‐N,O)­iron(III), [Fe­(C₁₀­H₈­NO)₃], (I), and aqua­bis(2‐methyl­quinolin‐8‐olato‐N,O)­copper(II), [Cu­(C₁₀­H₈NO)₂­(H₂O)], (II), have been determined. Compound (I) has a distorted octahedral configuration, in which the central Fe atom is coordinated by three N atoms and three O atoms from three 2‐methylquinolin‐8‐olate ligands. The three Fe—O bond distances are in the range 1.934 (2)–1.947 (2) Å, while the three Fe—N bond distances range from 2.204 (2) to 2.405 (2) Å. In compound (II), the central Cu^II atom and H₂O group lie on the crystallographic twofold axis and the coordination geometry of the Cu^II atom is close to trigonal bipyramidal, with the three O atoms in the basal plane and the two N atoms in apical positions. The Cu—N bond length is 2.018 (5) Å. The Cu—O bond length in the basal positions is 1.991 (4) Å, while the Cu—O bond length in the apical position is 2.273 (6) Å. There is an intermolecular OW—H?O hydrogen bond which links the mol­ecules into a linear chain along the b axis.     

Cerium triiodate,Ce(IO3)3

The crystal structure of Ce(IO₃)₃ consists of one‐dimensional chains of edge‐sharing CeO₉ polyhedra which are crosslinked into two‐dimensional layers through bridging IO₃⁻ groups. The layers are held together via long I⋯O contacts, resulting in an extended three‐dimensional network. The I—O bond distances and O—I—O angles are normal, lying in the ranges 1.806 (4)–1.846 (4) Å and 89.9 (2)–100.9 (2)°, respectively. The three crystallographically independent iodate groups all show different coordination modes.     

Na10(Na,Mn)7Mn43(PO4)36: a new synthetic fillowite‐type phosphate

Na₁₀(Na,Mn)₇Mn₄₃(PO₄)₃₆ (sodium manganese phosphate) was synthesized hydrothermally at 873 K and 0.35 GPa. The complex crystal structure is almost identical to that of natural fillowite‐type phosphates and can be described as a hexagonal packing of three types of rods parallel to the c axis. The rods are constituted by an alternation of five‐ to seven‐coordinated Mn sites [average Mn—O = 2.243 (3) Å], of six‐ to nine‐coordinated Na sites [average Na—O = 2.590 (3) Å], of PO₄ tetrahedra [average P—O = 1.548 (3) Å] and of cation vacancies.     

An additional methylene group driving the conformation and assembly of two arylsulfonamide para‐alkoxychalcone hybrids

The structures of two arylsulfonamide para‐alkoxychalcones, namely, N‐{4‐[(E)‐3‐(4‐methoxyphenyl)prop‐2‐enoyl]phenyl}benzenesulfonamide, C₂₂H₁₉NO₄S, (I), and N‐{4‐[(E)‐3‐(4‐ethoxyphenyl)prop‐2‐enoyl]phenyl}benzenesulfonamide, C₂₃H₂₁NO₄S, (II), reveal the effect of the inclusion of one –CH₂– group between the CH₃ branch and the alkoxy O atom on the conformation and crystal structure. Although the molecular conformations and one‐dimensional chain motifs are the same in both structures, their crystallographic symmetry, number of independent molecules and crystal packing are different. The crystal packing of (I) is stabilized by weak C—H...π and π–π interactions, while only C—H...π contacts occur in the structure of (II). The role of the additional methylene group in the crystal packing can also be seen in the fact that the alkoxy O atom is an acceptor in nonclassical hydrogen bonds only in the para‐ethoxy analogue, (II). The remarkable similarity between the crystal packing features of (I) and (II) lies in the formation of N—H...O hydrogen‐bonded ribbons, a synthon commonly found in related compounds.     

Weak intermolecular interactions in isomorphous 5‐(2‐chloroethoxy)‐2,3‐dihydro‐1,4‐benzodioxine and 5‐(2‐bromoethoxy)‐2,3‐dihydro‐1,4‐benzodioxine: bonding or nonbonding interactions

The title compounds, C₁₀H₁₁ClO₃, (I), and C₁₀H₁₁BrO₃, (II), are isomorphous and effectively isostructural; all of the interatomic distances and angles are normal. The structures exhibit long intermolecular C—H...O and C—H...π contacts with attractive energies ranging from 1.17 to 2.30 kJ mol⁻¹. Weak C—H...O hydrogen bonds form C(3) and C(4) motifs, combining to form a two‐dimensional R₃⁴(12) net. No face‐to‐face stacking interactions are observed.     

rac‐3‐Benzoyl‐2‐methylpropionic acid and its organic salts: possibilities of Yang photocyclization in crystals

The analysis of the crystal structures of rac‐3‐benzoyl‐2‐methylpropionic acid, C₁₁H₁₂O₃, (I), morpholinium rac‐3‐benzoyl‐2‐methylpropionate monohydrate, C₄H₁₀NO⁺·C₁₁H₁₁O₃⁻·H₂O, (II), pyridinium [hydrogen bis(rac‐3‐benzoyl‐2‐methylpropionate)], C₅H₆N⁺·(H⁺·2C₁₁H₁₁O₃⁻), (III), and pyrrolidinium rac‐3‐benzoyl‐2‐methylpropionate rac‐3‐benzoyl‐2‐methylpropionic acid, C₄H₁₀N⁺·C₁₁H₁₁O₃⁻·C₁₁H₁₂O₃, (IV), has enabled us to predict and understand the behaviour of these compounds in Yang photocyclization. Molecules containing the Ar—CO—C—C—CH fragment can undergo Yang photocyclization in solvents but they can be photoinert in the crystalline state. In the case of the compounds studied here, the long distances between the O atom of the carbonyl group and the γ‐H atom, and between the C atom of the carbonyl group and the γ‐C atom preclude Yang photocyclization in the crystals. Molecules of (I) are deprotonated in a different manner depending on the kind of organic base used. In the crystal structure of (III), strong centrosymmetric O...H...O hydrogen bonds are observed.     

Two different modes of halogen bonding in two 4‐nitroimidazole derivatives

In the crystal structures of the two imidazole derivatives 5‐chloro‐1,2‐dimethyl‐4‐nitro‐1H‐imidazole, C₅H₆ClN₃O₂, (I), and 2‐chloro‐1‐methyl‐4‐nitro‐1H‐imidazole, C₄H₄ClN₃O₂, (II), C—Cl...O halogen bonds are the principal specific interactions responsible for the crystal packing. Two different halogen‐bond modes are observed: in (I), there is one very short and directional C—Cl...O contact [Cl...O = 2.899 (1) Å], while in (II), the C—Cl group approaches two different O atoms from two different molecules, and the contacts are longer [3.285 (2) and 3.498 (2) Å] and less directional. In (I), relatively short C—H...O hydrogen bonds provide the secondary interactions for building the crystal structure; in (II), the C—H...O contacts are longer but there is a relatively short π–π contact between molecules related by a centre of symmetry. The molecule of (I) is almost planar, the plane of the nitro group making a dihedral angle of 6.97 (7)° with the mean plane of the imidazole ring. The molecule of (II) has crystallographically imposed mirror symmetry and the nitro group lies in the mirror plane.     

The effect of hydrogen bonding on the conformations of 2‐(1H‐indol‐3‐yl)‐2‐oxoacetamide and 2‐(1H‐indol‐3‐yl)‐N,N‐dimethyl‐2‐oxoacetamide

In the title compounds, C₁₀H₈N₂O₂, (I), and C₁₂H₁₂N₂O₂, (II), the two carbonyl groups are oriented with torsion angles of −149.3 (3) and −88.55 (15)°, respectively. The single‐bond distances linking the two carbonyl groups are 1.528 (4) and 1.5298 (17) Å, respectively. In (I), the molecules are linked by an elaborate system of N—H...O hydrogen bonds, which form adjacent R²₂(8) and R⁴₂(8) ring motifs to generate a ladder‐like construct. Adjacent ladders are further linked by N—H...O hydrogen bonds to build a three‐dimensional network. The hydrogen bonding in (II) is far simpler, consisting of helical chains of N—H...O‐linked molecules that follow the 2₁ screw of the b axis. It is the presence of an elaborate hydrogen‐bonding system in the crystal structure of (I) that leads to the different torsion angle for the orientation of the two adjacent carbonyl groups from that in (II).     

Substituent position effect on the crystal structures of N‐phenyl‐2‐phthalimidoethanesulfonamide derivatives

In order to determine the impact of different substituents and their positions on intermolecular interactions and ultimately on the crystal packing, unsubstituted N‐phenyl‐2‐phthalimidoethanesulfonamide, C₁₆H₁₄N₂O₄S, (I), and the N‐(4‐nitrophenyl)‐, C₁₆H₁₃N₃O₆S, (II), N‐(4‐methoxyphenyl)‐, C₁₆H₁₆N₃O₆S, (III), and N‐(2‐ethylphenyl)‐, as the monohydrate, C₁₈H₁₈N₂O₄S·H₂O, (IV), derivatives have been characterized by single‐crystal X‐ray crystallography. Sulfonamides (I) and (II) have triclinic crystal systems, while (III) and (IV) are monoclinic. Although the molecules differ from each other only with respect to small substituents and their positions, they crystallized in different space groups as a result of differing intra‐ and intermolecular hydrogen‐bond interactions. The structures of (I), (II) and (III) are stabilized by intermolecular N—H…O and C—H…O hydrogen bonds, while that of (IV) is stabilized by intermolecular O—H…O and C—H…O hydrogen bonds. All four structures are of interest with respect to their biological activities and have been studied as part of a program to develop anticonvulsant drugs for the treatment of epilepsy.     

A new linear bismuth coordination polymer based on 1,10‐phenanthroline‐2,9‐dicarboxylic acid: ionothermal synthesis,crystal structure and fluorescence properties

A new linear bismuth(III) coordination polymer, catena‐poly[[chloridobismuth(III)]‐μ₃‐1,10‐phenanthroline‐2,9‐dicarboxylato‐κ⁶O²:O²,N¹,N¹⁰,O⁹:O⁹], [Bi(C₁₄H₆N₂O₄)Cl]_n, has been obtained by an ionothermal method and characterized by elemental analysis, energy‐dispersive X‐ray spectroscopy, IR spectroscopy, thermal stability studies and single‐crystal X‐ray diffraction. The structure is constructed by Bi(C₁₄H₆N₂O₄)Cl fragments in which each Bi^III centre is seven‐coordinated by one Cl atom, four O atoms and two N atoms. The coordination geometry of the Bi^III cation is distorted pentagonal–bipyramidal (BiO₄N₂Cl), with one bridging carboxylate O atom and one Cl atom located in the axial positions. The Bi(C₁₄H₆N₂O₄)Cl fragments are further extended into a one‐dimensional linear polymeric structure via subsequent but different centres of symmetry (bridging carboxylate O atoms). Neighbouring linear chains are assembled via weak C—H...O and C—H...Cl hydrogen bonds, forming a three‐dimensional supramolecular architecture. Intermolecular π–π stacking interactions are observed, with centroid‐to‐centroid distances of 3.678 (4) Å, which further stabilize the structure. In addition, the solid‐state fluorescence properties of the title coordination polymer were investigated.     

Crystal structure and stability of Tl2CO3 at high pressures

The crystal structure of dithallium carbonate, Tl₂CO₃ (C2/m, Z = 4), was investigated at pressures of up to 7.4 GPa using single‐crystal X‐ray diffraction in a diamond anvil cell. It is stable to at least 5.82 GPa. All atoms except for one of the O atoms lie on crystallographic mirror planes. At higher pressures, the material undergoes a phase transition that destroys the single crystal.     

Carbonyl(5‐nitrotropolonato‐κ2O1,O2)(tri­phenyl­phosphine‐κP)­rhodium(I)

The molecule of the title complex, [Rh(5‐NO₂trop)(C₁₈H₁₅P)(CO)] (5‐­NO₂trop is 2‐hydroxy‐5‐nitrocyclo­hepta‐2,4,6‐trienone, C₇H₄NO₄), has a distorted square‐planar geometry. Strong intramolecular and weak intermolecular hydrogen bonding is observed, with H⋯O distances of the order of 2.25 and 2.55 Å, respectively. The Rh—CO, Rh—O (trans to CO), Rh—O (trans to P) and Rh—P bond distances are 1.775 (7), 2.072 (4), 2.068 (4) and 2.2397 (17) Å, respectively, the O—Rh—O angle is 77.09 (16)° and the bidentate O—C—C—O torsion angle is 1.5 (7)°.     

Three quinolone compounds featuring O...I halogen bonding

Ethyl 1‐ethyl‐6‐iodo‐4‐oxo‐1,4‐dihydroquinoline‐3‐carboxylate, C₁₄H₁₄INO₃, (I), and ethyl 1‐cyclopropyl‐6‐iodo‐4‐oxo‐1,4‐dihydroquinoline‐3‐carboxylate, C₁₅H₁₄INO₃, (II), have isomorphous crystal structures, while ethyl 1‐dimethylamino‐6‐iodo‐4‐oxo‐1,4‐dihydroquinoline‐3‐carboxylate, C₁₄H₁₅IN₂O₃, (III), possesses a different solid‐state supramolecular architecture. In all three structures, O...I halogen‐bonding interactions connect the quinolone molecules into infinite chains parallel to the unique crystallographic b axis. In (I) and (II), these molecular chains are arranged in (101) layers, viaπ–π stacking and C—H...π interactions, and these layers are then interlinked by C—H...O interactions. The structural fragments involved in the C—H...O interactions differ between (I) and (II), accounting for the observed difference in planarity of the quinolone moieties in the two isomorphous structures. In (III), C—H...O and C—H...π interactions form (100) molecular layers, which are crosslinked by O...I and C—H...I interactions.     

Synthesis and crystal structures of C24‐epimeric 20(R)‐ocotillol‐type saponins

Ocotillol‐type saponins have a wide spectrum of biological activities. Previous studies indicated that the configuration at the C24 position may be responsible for their stereoselectivity in pharmacological action and pharmacokinetics. Natural ocotillol‐type saponins share a 20(S)‐form but it has been found that the 20(R)‐stereoisomers have different pharmacological effects. The semisynthesis of 20(R)‐ocotillol‐type saponins has not been reported and it is therefore worthwhile clarifying their crystal structures. Two C24 epimeric 20(R)‐ocotillol‐type saponins, namely (20R,24S)‐20,24‐epoxydammarane‐3β,12β,25‐triol, C₃₀H₅₂O₄, (III), and (20R,24R)‐20,24‐epoxydammarane‐3β,12β,25‐triol monohydrate, C₃₀H₅₂O₄·H₂O, (IV), were synthesized, and their structures were elucidated by spectral studies and finally confirmed by single‐crystal X‐ray diffraction. The (Me)C—O—C—C(OH) torsion angle of (III) is 146.41 (14)°, whereas the corresponding torsion angle of (IV) is −146.4 (7)°, indicating a different conformation at the C24 position. The crystal stacking in (III) generates an R₄⁴(8) motif, through which the molecules are linked into a one‐dimensional double chain. The chains are linked via nonclassical C—H…O hydrogen bonds into a two‐dimensional network, and further stacked into a three‐dimensional structure. In contrast to (III), epimer (IV) crystallizes as a hydrate, in which the water molecules act as hydrogen‐bond donors linking one‐dimensional chains into a two‐dimensional network through intermolecular O—H…O hydrogen bonds. The hydrogen‐bonded chains extend helically along the crystallographic a axis and generate a C₄⁴(8) motif.