Calorimetric investigations of 2-[4-n-alkylphenyl]-5-[4-n-alkyloxyphenyl]-pyrimidines

We investigated temperatures and enthalpies of the phase transitions by means of the calorimeter DSC-2. The kinetics of polymorphic transitions in the solid state, the pretransitional behaviour in the liquid crystalline phases and the transition enthalpies, ranging from 3 J/mol up to 50 kJ/mol, in relation to the occurrence of the liquid crystalline phase types S_G, S_F, S_C, S_A, and N are points of discussion.     

Physical Properties of Liquid Crystalline 5-n-Hexyl-2-(4-n-alkyloxyphenyl)-pyrimidines

In 8 compounds of the substance class 5-n-hexyl-2-(4-n-alkyloxyphenyl)-pyrimidines the clearing temperatures, transition enthalpies, densities and refractive indices were measured. Packing fractions, pressure dependence of the clearing temperatures, polarizabilities, order parameters and the anisotropy of the local field were calculated.     

The structure of ethyl allyl 1,4-dihydro-2,6-dimethyl-4-[4-(4H-4-oxo-1-benzopyran-2-yl)phenyl]-3,5-pyridine dicarboxylate

The crystal and molecular structure of the title compound has been determined by direct methods, and refined to a finalR of 0.070 for 1466 observed reflections. The compound crystallizes in space group P2_l/n with cell dimensionsa=10.706(8),b=21.127(11),c=12.038(10) Å, Z=4.1,4-dihydropyridine ring adopts a boat shaped conformation. The flavon molecule is planar and it's phenyl ring is almost perpendicular to the 1,4-DHP. The C36 atom of the allyl group shows disorder.     

Crystal structure of 3-amino-5-acetyl-4,7-dihydro-6-methyl-4-(2-nitrophenyl)-2-cyanothieno[2,3-b]-pyridine and specific features of its molecular packing in crystal

The molecular and crystal structures of 3-amino-5-acetyl-4,7-dihydro-6-methyl-4-(2-nitrophenyl)-2-cyanothieno[2,3-b]-pyridine is determined by X-ray diffraction. The unit-cell parameters are as follows: a = 14.68(1) Å, b = 8.704(5) Å, c = 25.36(1) Å, V = 3241(6) ų, d _calcd = 1.453 g/cm³, Z = 8(1,1), and space group Pna2₁. Theo-nitrophenyl substituent is synperiplanar relative to the hydrogen atom at the C(4) atom of the heterocycle. Two crystallographically independent reference molecules A and B in the structure can be considered a pair of the enantiomers related by an approximate noncrystallographic center of inversion. The degree of approximation of this pseudocenter is discussed. It is shown that the structure can be described as a combination of two systems of translationally equal layers. The pseudosymmetry of the crystal structure and the possibility of forming a similar molecular packing with a higher crystallographic symmetry are considered.     

Crystal structure of 4-[benzylideneamino]-3-thiophen-2-yl-methyl-4,5-dihydro-1H-[1,2,4]triazole-5-one

The crystal structure of the title compound C₁₄H₁₂N₄OS was determined by the X-ray diffraction method. The compound crystallizes in the triclinic space group $P\bar 1$ with Z = 2. The molecule is not planar: the dihedral angle between the triazole and thiophene rings is 73.98(2)°, and that between the triazole and benzene rings is 4.05(2)°. The thiophene ring is disordered over two positions, which are approximately parallel and oppositely oriented. The major component refined to a site-occupancy factor of 0.573(3). An intramolecular C-H...O hydrogen bond generates an S(6) ring motif. In the crystal, molecules are linked together by two pairs of N-H...O interactions (to the same O atom as acceptor), forming inversion dimers. The crystal packing is also stabilized by π-π interactions [centroid-centroid distance is 3.978 Å].     

Structure of 4-methyl-N-{2-[2-alkylamino-5-nitrophenyliminomethyl]phenyl}benzenesulfonamides

The structures of Schiff bases prepared by the condensation of 2-tosylaminobenzaldehyde with 2-alkylamino-5-nitroanilines were studied by X-ray diffraction. The intramolecular N-H…N hydrogen bonds result in the closure of six-membered hydrogen-bonded rings, which are either planar or nonplanar depending on the substituent. According to the results of quantum-chemical calculations, the distortion of the hydrogen-bonded ring is associated with the character of molecular packing in the crystal.     

Synthesis and structure of 4-R,5-R-[5-(hydroxy-diphenyl-methyl)-2, 2-dimethyl-[1,3]dioxolan-4-yl]-phenyl-methanone, a chiral ligand building block

A triphenyl analog of taddol, 4-R,5-R-[5-(hydroxy-diphenyl-methyl)-2,2-dimethyl-[1,3]dioxolan-4-yl]-phenyl-methanone, has been synthesized and structurally characterized. This molecule could act as a chiral ligand building block in the creation of tuned taddol analogs. Structural analysis of the title compound reveals that the hydroxyl group is involved in an intramolecular hydrogen bond and does not take part in any intermolecular interaction. Crystal packing is influenced by C–H O hydrogen bonding and phenyl phenyl interactions. Crystal data: Triclinic, P1 (No. 1), a = 5.9343(4) Å, b = 8.2367(17) Å, c = 10.987(2) Å, = 88.290(6), = 75.442(4), = 80.655(6), V = 512.86(15) ų, Z = 1, D _calc = 1.258 mg/m³. Final residual values were R ₁ = 0.0407 for 3022 observed data (I > 2s(I) ) and wR ₂ = 0.0941 for all 3524 unique data.     

Synthesis and Crystal Structure of [2-(4-chlorobenzoyloxy)-5-methylphenyl]-(4-methylphenyl)methanone

[2-(4-Chlorobenzoyloxy)-5-methylphenyl]-(4-methylphenyl)methanone was synthesized and characterized by spectroscopic and X-ray diffraction methods. The molecule crystallizes in the monoclinic space group P2₁/c with cell parameters a = 13.7530(19) Å, b = 10.0560(19) Å, c = 13.469(3) Å, β = 100.630(7)° and Z = 4. There is a large discrepancy between the carbonyl group bond lengths of ketone and the ester. The structure exhibits intermolecular hydrogen bonds of the type C–H···O.     

The synthesis and crystal structure of 2-[4(S)-4,5-dihydro-4-phenyl-2-oxazolinyl]-benzenamine, and 2-[4(S)-4,5-dihydro-4-benzyl-2-oxazolinyl]-benzenamine

Two oxazolines compound 1a and 1b, 2-[4(S)-4,5-dihydro-4-phenyl-2-ozazolinyl-benzenamine, and (C₁₅H₁₄N₂O), 2-[4(S)-4,5-dihydro-4-benzyl-2-ozazolinyl-benzenamine (C₁₆H₁₆N₂O) were obtained in moderate yield from the reactions of 2-aminobenzonitrile with optically active L-(+)-Phenylglycinol and L-(+)-Phenylalaninol, respectively, in chlorobenzene under dry, anaerobic conditions. ZnCl₂ was dried under vacuum and acted as a Lewis acid catalyst in this reaction. The structures of 1a and 1b were determined by X-ray diffraction and NMR. There exist intra- and intermolecular N-H…N hydrogen bonds in the crystal structure.     

Crystal and Molecular Structure of the Smectogen 1-[4-n-heptylbenzoyl]-2-[cyanoacetyl]-hydrazine

The compound 1-[4-n-heptylbenzoyl]-2-[cyanoacetyl]-hydrazine crystallizes in the triclinic space group Pl̄ with two molecules in the unit cell and the lattice parameters a = 4.702, b = 8.640, c = 20.906 Å, a = 97.50, β = 92.79, γ = 100.19°. The structure was solved by direct methods and refined by full-matrix least squares calculations to the final residual value R = 0.039.     

Crystallographic and conformational analysis of 2-methyl-3-(2-nitro-phenyl)-4-phenyl-[1,2,4]oxadiazolidin-5-one

Molecular and crystal structure of 2-methyl-3-(2-nitro-phenyl)-4-phenyl-[1,2,4]oxadiazolidin-5-one, C₁₅H₁₃N₃O₄, have been determined by single crystal X-ray diffraction study. The title compound is monoclinic, with a = 10.0313(8) Å, b = 9.0372(5) Å, c = 15.5964(14) Å, β = 96.926(7)^∘, Z = 4, D_x = 1.42 g/cm³, μ (Mo-K_α) = 0.105 mm⁻¹, and space group is P 2₁/c. The structure was solved by direct methods and refined to a final R = 0.036 for 1894 reflections with I > 4σ (I). The crystal structure is stabilized by C–H⋅sO type inter-molecular, C–H⋅sN and C–H⋅sO type intra-molecular, π–π stacking and edge to face (C–H⋅s π-ring) interactions. To enlighten conformational flexibility of the title molecule, selected two torsion angles are varied from −180^∘ to +180^∘ in every 10^∘ separetely and then molecular energy profile is calculated and construed.     

Molecular Structure and Supramolecular Architecture of Brivanib: (R)-1-(4-(4-Fluoro-2-methyl-1H-indol-5-yloxy)-5-methylpyrrolo[2,1-f] [1,2,4]triazin-6-yloxy)propan-2-ol

Crystallography Reports - Crystal structure of brivanib ((R)-1-(4-(4-fluoro-2-methyl-1H-indol-5-yloxy)-5-methylpyrrolo[2,1-f][1,2,4]triazin-6-yloxy)propan-2-ol) is reported for the first time....     

Cluster self-organization of TR,Ge-containing crystal-forming systems: Suprapolyhedral precursors and self-assembly of La3Ga[6]Ga 4 [4] Ge[4]O14 (langasite) and La3Ge[6]Ge 2 [5] Ge 2 [4] Ga[4]O16 gallogermanates

A combinatorial-topological analysis of the La₃Ga^[6]Ga ₄ ^[4] Ge^[4]O₁₄ and La₃Ge^[6]Ge ₂ ^[5] Ge ₂ ^[4] Ga^[4]O₁₆ gallogermanates, which have MT and MPT microporous frameworks composed of M octahedra (GeO₆, GaO₆), T tetrahedra (GeO₄, GaO₄), and P pyramids (GeO₅), is performed using the method of coordination sequences with the TOPOS 3.2 program package. It is established that the La₃Ga^[6]Ga ₄ ^[4] Ge^[4]O₁₄ gallogermanate is characterized by a crystal-forming net 6 6 6 (of the graphite type). A new type of the binodal net 6 10 1 0 + 6 10 (2: 1) is revealed in the La₃Ge^[6]Ge ₂ ^[5] Ge ₂ ^[4] Ga^[4]O₁₆ gallogermanate. The cyclic cluster precursors composed of six polyhedra with a lanthanum template atom at the center of the LaMT ₅ and LaMP ₃ T ₃ clusters are identified by the two-color decomposition of the nets in the structures of the La₃Ga^[6]Ga ₄ ^[4] Ge^[4]O₁₄ and La₃Ge^[6]Ge ₂ ^[5] Ge ₂ ^[4] Ga^[4]O₁₆ gallogermanates. The coordination numbers of the cluster precursors in these structures are found to be equal to 6 and 4 for two-dimensional nets and 8 and 6 for three-dimensional nets, respectively.     

Dielectric and Electrooptic Investigations in the Nematic Phase of 5-n-Pentyl-2-[4-n-nonyloxyphenyl]-1,3-dioxane

The dielectric constant and the dielectric loss of 5-n-pentyl-2-[4-n-nonyloxyphenyl]-1,3-dioxane were investigated in the region of 0.1 to 10 MHz. An isotropy temperature was detected, at which the static dielectric anisotropy Δε₀₁ = 0. Using both the Freedericksz and the DAP effect, we measured the frequency dependence of the threshold voltage U₀ and compared the results with those of the dielectric measurements. In the case of DAP effect we could find two different types of dispersions curves of U₀.     

N-[[5-[[(1,4-二氢-2-甲基-4-氧-6-喹唑啉基)甲基]甲氨基]-2-噻吩基]羰基]-L-谷氨酸的一水合甲醇溶剂合物的合成、晶体结构及Hirshfeld表面分析

合成制备了N-[[5-[[(1,4-二氢-2-甲基-4-氧-6-喹唑啉基)甲基]甲氨基]-2-噻吩基]羰基]-L-谷氨酸的一水合甲醇溶剂合物(C21H22N4O6S·CH3OH·H2O(化合物1)的晶体,通过单晶X射线衍射,红外,热重分析表征.分析其含有一个结晶水和一分子甲醇溶剂,晶胞参数为a=7.9730(16)nm,b=13.558(3)nm,c=11.412(2)nm,α=90°,β=91.12(3)°,γ=90°.采用Hirshfeld表面分析方法对分子间作用力分析.Hirshfeld表明作用分析得到的二维指纹图显示,其中O…H,N…H,C…H,S…H的作用力要强与C…O,C…N作用力,其中H…H作用力明显.     

4-(E)-2-[3-(3-[(E)-2-(4-cyanophenyl)-1-diazenyl]perhydrobenzo[d]imidazol-1-ylmethyl)perhydrobenzo[d]imidazol-1-yl]-1-diazenylbenzonitrile: X-ray crystal structure

4-(E)-2-[3-(3-[(E)-2-(4-Cyanophenyl)-1-diazenyl]perhydrobenzo[d]imidazol-1-ylmethyl) perhydrobenzo[d]imidazol-1-yl]-1-diazenylbenzonitrile (1) has been synthesized by reac- tion of p-cyanobenzene diazonium chloride with a mixture of formaldehyde and trans-1,2-cyclohexanediamine. The crystal structure has been determined by single crystal X-ray diffraction analysis. The bis-triazene (1) does not adopt a folded conformation, unlike previously studied ethylenediamine analogues, and there is no indication of -stacking in the crystal packing. The dominant interaction between molecules is the van der Waal's attraction between cyclohexane rings. This result establishes the structure of the product of this diazonium coupling reaction as the 1-(1-imidazolidinylmethyl)imidazolidine derivative and not the alternate tetraazabicyclo[4.4.1]undecane derivative. Crystal data: 1 C₂₉H₃₄N₁₀, orthorhombic, space group Pbca, a = 17.946(1), b = 13.106(1), c = 24.108(1) Å, V = 5670.6(3) ų, for Z = 8.     

Crystal Structures of N-[2-(4-oxo-4H-benzo[d] [1, 3]-oxazin-2-yl)benzamide and Propionamide and Their N-Containing Analog N-[2-(4-oxo-3,4-dihydroquinazolin-2-yl)phenyl]propionamide

Crystallography Reports - Specific features of the molecular and crystal structures of two substituted benzoxazinones (I and II) and their structural analog quinazolinone (III) have been analyzed...