Electronic nature of substituents and the structure of 4,4′-dipyridylium dications: Crystal structure of <Emphasis Type="Italic">N,N′</Emphasis>-di(2-carboxyethyl)-4,4′-dipyridylium diperchlorate

The crystal structure of N,N′-di(2-carboxyethyl)-4,4′-dipyridylium diperchlorate, C₁₆H₁₈Cl₂N₂O₁₂, is determined using X-ray diffraction analysis at 293 K. The crystals are orthorhombic, a = 20.084(4) Å, b = 8.687(2) Å, c = 11.725(2) Å, space group Pna2₁, and Z = 4; 1688 reflections measured; and R = 0.056 and R _w = 0.059 for 1244 reflections with I > 3σ(I). It is found that, in the absence of charge transfer or short intramolecular O?N contacts, the nucleus of the dication adopts a twist conformation (the angle of rotation between the planes of the pyridine rings is equal to 23°).     

Single-crystal structures of high-pressure phases FeOOH,FeOOD, and GaOOH

The structures of the ?-FeOOH, ?-FeOOD, and β-GaOOH phases, which belong to the InOOH structure type (the distorted TiO₂ structure type), are determined using single-crystal X-ray diffraction analysis. The measurements are performed on Xcalibur CCD and CAD-4F diffractometers. The calculations are carried out in space group P2_1nm with the JANA2000 program. The crystals are twinned and form aggregates related by the rotation around the b axis through an angle close to 62°. In the same crystals, the merohedral twinning is characterized by the rotation around the c axis through an angle of 180°. The alternation of these twin domains in the bulk of the crystal determines the corresponding disordering of the hydrogen positions.     

Refinement of the twinned structure of cymrite from the Ruby Creek deposit (Alaska)

The mineral cymrite from the Ruby Creek deposit (Alaska) was reinvestigated by X-ray diffraction in a pseudo-orthorhombic unit cell with a = 5.3350(1) Å, b = 36.9258(8) Å, c = 7.6934(1) Å, β = 90.00(1)°. A twin law corresponding to a sixfold axis was revealed for the first time. The structure was refined in the monoclinic space group P12₁1 to the R factor of 5.4%. The Al and Si atoms are assumed to be ordered within a double layer. The rotation of the cation sublattice by 60° around the c axis leads to the disorder of the T sites in the crystal structure (T = Al, Si).     

Novel Polyoxovanadate K<Subscript>2</Subscript>ZnV<Subscript>5</Subscript>O<Subscript>14</Subscript>: Crystal Structure and Peculiarities of Crystal Chemistry

A novel structure type has been established as a result of studying a non-merohedral microtwin of polyoxovanadate (K₂ZnV₅O₁₄) by X-ray diffractometry (R = 0.0595). The new compound, synthesized under hydrothermal conditions in the ZnCl₂–K₂CO₃–V₂O₅–H₂O system, is characterized as follows: a = 8.066(5) Å, b = 8.117(5) Å, c = 9.236(5) Å, β = 105.287(5)°, sp. P2₁/m, Z = 2, ρ_calcd = 3.54 g/cm³. Edge-shared five-core “clusters” consisting of vanadium octahedra, between which ZnO₄ tetrahedra (sharing vertices with octahedra) are located, form two-dimensional two-layer anion packets of the (ZnV₅O₁₄)^2– composition, alternating along the c axis with layers of potassium atoms. Structural peculiarities determine the morphology and color of new-phase crystals.     

On the structural basis of the presence of two optical axes in α-HIO<Subscript>3</Subscript> crystal

An X-ray diffraction study of α-HIO₃ crystal has been performed with the following results: sp. gr. P2₁2₁2₁, Z = 4, a = 5.5360(3) Å, b = 5.8723(6) Å, c = 7.7291(5) Å, and R factors R(F)/wR(F) = 0.86/0.69%. Disordering of iodine site is revealed, which is described in terms of anharmonic atomic displacements. Packing (likely unique) of all structure atoms over two systems of planes rotated by an angle close to the rotation of optical axes (47°) is revealed. The rotation of the plane of polarization of light based on the structural data is calculated for the first time for the α-HIO₃ crystal.     

Synthesis and Molecular Structures of (3-Hydroxy, 3-Chloro, 3-Arylamino)-<Emphasis Type="Italic">N</Emphasis>-acetyl-3-arylaminotropones

The structures of 5,7-di(tert-butyl)-2-(5,8-dimethyl-4-piperidinoquinolin-2-yl)-3-hydroxytropone, 5,7-di(tert-butyl)-3-chloro-2-(5,8-dimethyl-4-piperidinoquinolin-2-yl)tropone, 5,7-di(tert-butyl)- 3-(3,5-dimethylphenylamino)-2-(5,8-dimethyl-4-piperidinoquinolin-2-yl)tropone, and 3-(N-acetyl-3,5- dimethylphenylamino)-5,7-di(tert-butyl)-2-(5,8-dimethyl-4-piperidinoquinolin-2-yl)tropone were determined by X-ray diffraction. These compounds were synthesized through a series of transformations, including the nucleophilic substitution of the chlorine atom by piperidine in the starting 5,7-di(tert-butyl)-2-(4- chloroquinolin-2-yl)-3-hydroxytropone followed by the three-step functionalization of the 3-position in 3-hydroxytropone. The nature of dynamic processes in a solution of N-acetyl-3-arylaminotropone associated with the rotation of the N-acetyl group was revealed by the PCM/PBE0/6-31G(d,p) method.     

Synthesis and characterization of 9-(4-nitrophenyl)3,3,6,6-tetramethyl-3,4,6,7,9,10-hexahydro-1,8(2H,5H) acridinedione and its methoxyphenyl derivative

9-(4-Nitrophenyl)-3,3,6,6-tetramethyl-3,4,6,7,9,10-hexahydro-1,8(2H,5H) acridinedione (NTHA) crystallizes in orthorhombic space group P2₁2₁2₁ with a = 5.9716(1) Å, b = 18.0476(3) Å, c = 19.2445(2) Å, V = 2074.04(5) ų, Z = 4, D_cal = 1.263 Mg m^?3 and R = 0.0521 (wR = 0.1326) for 4078 observed reflections. 9-(4-Nitrophenyl)-10-(4-methoxyphenyl)-3,3,6,6-tetramethyl-3,4,6,7,9,10-hexahydro-1,8(2H,5H) acridinedione NMTHA, crystallizes in monoclinic space group P2₁/c with a = 15.669(5) Å, b = 10.652(4) Å, c = 18.337(6) Å, β = 108.25(1)^°, V = 2906.66(2) ų, Z = 4, D_cal = 1.245 Mg m^?3 and R = 0.0725 (wR = 0.1847) for 5105 observed reflections. The experimental values are compared with the theoretical values calculated based on the semiemperical methods. The structures are stabilized by N–H?sO and C–H?sO types of intermolecular interactions in addition to van der Waals forces.     

Crystal Structure of 4-Amino-3-(thiophen-2-ylmethyl)-1H-1,2,4-triazole-5(4H)one Monohydrate

The molecular structure of the 4-amino-3-(thiophen-2-ylmethyl)-1H-1,2,4-triazole-5(4H)one monohydrate was determined by X-ray diffraction. The compound crystallizes in the monoclinic sp. gr. C2/c with Z = 4 in the unit cell. The title compound is not planar. The dihedral angle between the thiophene and 1,2,4-triazole rings is 73.4(5)°. In the crystal structure, the molecules are connected by intermolecular N–H···O, N–H···N, O–H···O, and C–H···N type hydrogen bonds. The N–H···N and C–H···N hydrogen bonds link the molecules into infinite chains along the c axis.     

Synthesis of Nonstoichiometric Samarium Fluoride SmF<Subscript>2 + <Emphasis Type="Italic">x</Emphasis></Subscript>

The products of interaction of SmF₃ with metallic Sm⁰, Si, and molecular hydrogen in quartz, graphite, and molybdenum containers have been investigated by X-ray diffraction. It is shown that reduction occurs with the formation of nonstoichiometric cubic SmF_{2 + x} (sp. gr. Fm3?m, unit-cell parameter a = 5.8517(2) Å) with a content x = 0.108 only in the case of synthesis of SmF₃ with metallic Sm⁰ in a quartz ampoule. The transformation of the SmF_{2 + x} phase composition in air at room temperature has been studied for the first time. It is found that SmF_2.108 passes into the superstructural phase Sm₁₃F_32–δ (sp. gr. R3?) with the unit-cell parameters a = 14.7354(4) Å and c = 10.1156(4) Å for 60 days. The use of Sm⁰, Si, and H₂ as reducing agents for SmF₃ is inefficient because of the weak tendency of the latter to reduction: the process occurs also with a low yield of the Sm₁₃F_32–δ phase and of the α-SmF₃-based phase as impurity in the case of direct reduction by hydrogen.     

Synthesis,Crystal Structure,and Topology–Symmetry Analysis of a New Modification of NaIn[IO<Subscript>3</Subscript>]<Subscript>4</Subscript>

Crystals of new iodate NaIn[IO₃]₄ were prepared by the hydrothermal synthesis. The unit cell parameters are a = 7.2672(2) Å, b = 15.2572(6) Å, c = 15.0208(6) Å, β = 101.517(3)°, sp. gr. P2₁/c. The formula was determined during the structure determination and refinement of a twinned crystal based on a set of reflections from the atomic planes of the major individual. The refinement with anisotropic displacement parameters was performed for both twin components to the final R factor of 0.050. The In and Na atoms are in octahedral coordination formed by oxygen atoms. The oxygen octahedra are arranged into columns by sharing edges, and the columns are connected by isolated umbrella-like [IO₃]^– groups to form layers. The new structure is most similar to the isoformular iodate NaIn[IO₃]₄, which crystallizes in the same sp. gr. P2₁/c and is structurally similar, but has a twice smaller unit cell and is characterized by another direction of the monoclinic axis. The structural similarity and difference between the two phases were studied by topologysymmetry analysis. The formation of these phases is related to different combinations of identical one-dimensional infinite chains of octahedra.     

Crystal Structure of Cl-Deficient Analogue of Taseqite from Odikhincha Massif

An eudialyte group mineral, found in pegmatites of the Odikhincha massif (the northern part of the Siberian platform), has been investigated using X-ray diffraction, IR spectroscopy, and Raman spectroscopy. The mineral is characterized by a high strontium content and a low chlorine content. It has a trigonal unit cell with the following parameters: a = 14.2700(6) Å and c = 30.057(1) Å; V = 5300.6(1) ų; sp. gr. R3m. The structure has been refined to R = 0.047 in the anisotropic approximation of atomic displacements using 1697F > 4σ(F). The idealized formula (Z = 3) was found to be Na₁₂Sr₂Ca₆Fe ₃ ²⁺ Zr₃NbSi₂₅O₇₂(OH,O)₄Cl(Н₂О)_0.2. The chemical composition and structure of this mineral are close to those of taseqite; however, it differs from the holotype sample by a low chlorine content and peculiarities of cation distribution over basic structure sites. A comparative analysis of strontium-rich eudialytes has revealed their important crystallochemical feature: selective concentration of strontium in the N4 site. Thus, taseqite, along with heterophyllosilicates, may play a role of strontium concentrator in agpaitic pegmatites.     

Crystal and molecular structure of [5,10,15,20-tetrakisphenyl-2-ethoxy-3-oxa-chlorinato]Ag(II)

The silver(II) complex of the chlorin-like derivativev [5,10,15,20-tetrakisphenyl-2-ethoxy-3-oxa-chlorinato]Ag(II) (1Ag), formally formed by substitution of one pyrrolic subunit in silvermeso-tetraphenylporphyrin by one ethoxy-substituted hydrooxazole moiety, crystallizes in the tetragonal space groupI4/m witha = 13.4811(10) Å,c = 9.7361(13) Å, andZ = 2. The molecule, which is asymmetric, accommodates the high-symmetry space group by rotational disorder with the silver atom located on the four-fold axis.     

Crystal structure of <Emphasis Type="Italic">p</Emphasis>-carboxyphenylhydrazone benzoylacetone

The crystal structure of p-carboxyphenylhydrazone benzoylacetone is determined. The crystals are monoclinic, a = 13.614(4) Å, b = 11.388(2) Å, c = 20.029(6) Å, β = 104.82(2)°, V = 2339(9) ų, Z = 8, space group C2/c, and R = 0.038 for 1622 reflections with I > 2σ(I). The crystal is built of C₁₇H₁₄N₂O₄ neutral molecules that are linked by O-H?O hydrogen bonds between the carboxyl groups into centrosymmetric pseudodimers. The effect of carboxylation of the phenylhydrazone fragment and the position of the carboxyl group on the molecular packing in the crystal is determined. The N(1)-H(1N)?O(1) intramolecular hydrogen bond (N-H, 0.94 Å; H?O, 1.87 Å; N?O, 2.59 Å; and the N-H?O angle, 133°) is formed in the molecule.     

Synthesis and crystal structure of the iridium(I) carbene complex with a pair of hydrogen wing tips

The iridium(I) cyclooctadiene complex with two (3-tert-butylimidazol-2-ylidene) ligands [(H-Im^tBu)₂Ir(COD)]⁺PF₆^? (C₂₂H₃₂PF₆IrN₄) has been prepared, and its crystal structure is determined by X-ray diffraction. Complex exhibits slightly distorted square planar configurations around the metal atom, which is coordinated by two H-Im^tBu ligands and one cyclooctadiene group. The new iridium carbene complex has a pair of hydrogen wing tips. The Ir?C_carbene bond lengths are 2.066(5) and 2.052(5) Å, and the bond angle C?Ir?C between these bonds is 95.54(19)°. The dihedral angle between two imidazol-2-ylidene rings is 86.42°.     

X-ray crystallography of methyl (6-amino-5-cyano-2-methyl-4-(2-nitrophenyl)-4<Emphasis Type="Italic">H</Emphasis>-pyran)-3-carboxylate

The organic carbonitrile namely methyl (6-amino-5-cyano-2-methyl-4-(2-nitrophenyl)-4H-pyran)- 3-carboxylate is synthesized via one-pot multi-component reaction at room temperature using commercially available urea as inexpensive and environmentally benign organo-catalyst and its crystal structure is determined by X-ray technique. The crystals are monoclinic, sp. gr. C2/c, a = 12.3069(8) Å, b = 9.7023(7) Å, c = 24.812(2) Å, β = 94.862(6)°, Z = 8. The dihedral angle between pyran and phenyl rings is 87.8(1)°; the pyran ring is almost planar The dihedral angle between the mean planes of phenyl ring and nitro group is 44.4(2)°. The crystal structure is stabilized by N?H···N and N?H···O hydrogen bonds. In addition, C?H···π interactions are also observed in the crystal structure.     

Synthesis,Crystal Structure,Antioxidant, and α-Glucosidase Inhibitory Activities of Methoxy-substituted Benzohydrazide Derivatives

Eight methoxy substituted at the benzylidene moiety benzohydrazide derivatives [R = 2-OCH₃ (1), 3-OCH₃ (2), 4-OCH₃ (3), 2,3-(OCH₃)₂ (4), 3,4-(OCH₃)₂ (5), 2,4,5-(OCH₃)₃ (6), 2,4,6-(OCH₃)₃ (7), and 3,4,5-(OCH₃)₃ (8)] were synthesized and characterized by ¹H NMR, FT-IR and UV-Vis spectroscopy. The crystal structure of 4 was determined by single crystal X-ray diffraction (sp. gr. Pbca, Z = 8). The molecule is slightly twisted with the dihedral angle between the two phenyl rings being 9.33(14)°. The methoxy group at the ortho position is twisted [C–O–C–C angle is–109.2(3)°] whereas the other at meta position is co-planar with the attached benzene ring. In the crystal packing, the molecules are linked into two-dimensional network parallel to the (001) plane by O–H···O, O–H···N, and N–H···O hydrogen bonds. Compounds 1–8 were evaluated for an antioxidant and α-glucosidase inhibitory activities and the results suggested that the ?OCH₃ substituent was ineffective for bioactivity enhancement.     

Synthesis,Crystal Structure,Electrochemical Properties,and Biological Activity of 2-((1H-Benzimidazol-2-yl)methylamino)acetic Acid

A water soluble compound, (2-((1H-benzimidazol-2-yl)methylamino)acetic acid, BIGH, has been synthesized and structurally characterized by elemental analysis, IR and UV spectroscopies, ¹H-NMR, thermogravimetric and differential thermal analyses, and single crystal and powder X-ray diffraction. BIGH can act as a flexible planar ligand with three potential coordination sites. It crystallizes in a monoclinic system with the sp. gr. P2₁/c with the unit cell parameters, a = 9.3764(7) Å, b = 11.5031(8) Å, c = 10.0543(6) Å, and Z = 4. The crystal structure was stabilized through inter-molecular hydrogen bonds. The anti-microbial activity of the compound has been studied against Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Staphylococcus aureus, which showed a good activity against Bacillus subtilis. Cyclic voltammogram of the compound shows that it is a redox-active molecule.     

X-ray mapping in heterocyclic design: 16. X-ray diffraction study of 1-(4-chlorophenacyl)-4-methyl-1,5,6,7-tetrahydro-2<Emphasis Type="Italic">H</Emphasis>-cyclopenta[<Emphasis Type="Italic">b</Emphasis>]pyridin-2-one

The structure of 1-(4-chlorophenacyl)-4-methyl-1,5,6,7-tetrahydro-2H-cyclopenta[b]pyridin-2-one is studied using single-crystal X-ray diffraction. The structure (a = 37.006(8) Å, b = 8.967(3) Å, c = 27.911(3) Å, β = 96.52(2)°, Z = 24, space group P2₁/c) is solved by direct methods and refined to R₁ = 0.0608 and wR₂ = 0.1170. Six crystallographically independent molecules differ in the dihedral angle between the phenyl and heterocycle planes. The formation of Cl?Cl aggregates is discussed.     

New Data on Isomorphism in Eudialyte-Group Minerals. I. Crystal Structure of Titanium-Rich Eudialyte from the Kovdor Alkaline Massif

An abnormally titanium-rich mineral of the eudialyte group was studied by IR spectroscopy and X-ray diffraction. The trigonal unit cell parameters are a = 14.165(1) Å, c = 30.600(5) Å, V = 5317.23(4) ų, sp. gr. R3m. The crystal structure was refined to R = 0.034 with anisotropic displacement parameters using 2530 reflections with F > 3σ(F). The idealized formula of the mineral (Z = 3) is Na₈(H₃O)₅(K,Ce,Sr)₂Ca₆Zr₂Ti_1.2(Fe,Mn)_0.6Si₂₆O₇₂(OH)₂Cl · 4H₂O. At the ratio Zr: Ti ~ 2: 1, titanium atoms lie in four sites and are not predominant in any of them. Another distinguishing feature of the mineral is the structural separation of chemical elements, such that K, Sr, and Ce cations and H₃O groups are randomly distributed between four split sites to form polyhedra with different volumes. The isomorphism of Zr and Ti in eudialyte-group minerals is discussed.     

Crystal structure and microtwinning of monoclinic La<Subscript>3</Subscript>SbZn<Subscript>3</Subscript>Ge<Subscript>2</Subscript>O<Subscript>14</Subscript> crystals of the langasite family

The crystal structure of monoclinic La₃SbZn₃Ge₂O₁₄ crystals from the langasite family is determined by X-ray diffraction analysis [a = 5.202(1) Å, b = 8.312(1) Å, c = 14.394(2) Å, β = 90.02(1)°, sp. gr. A2, Z = 2, and R/R _w = (5.2/4.6)%]. The structure is a derivative of the Ca₃Ga₂Ge₄O₁₄-type structure (a = 8.069 Å, c = 4.967 Å, sp. gr. P321, Z = 1). The crystal studied is a polysynthetic twin with the twin index n = 2, whose monoclinic components are related by pseudomerohedry by a threefold rotation axis of the supergroup P321.