Synthesis and structure of 1-methyl-4-(3-thiocarbamoyl-3-cyanopropenylidene)-1,4-dihydroquinoline

1,4-Dimethylquinolinium iodide reacts with (2-nitrophenyl)aminomethylenecyano-thioacetamide in the presence of triethylamine to give 1-methyl-4-(3-thiocarbamoyl-3-cyanopropylidene)-1,4-dihydroquinoline, the structure of which has been established by x-ray crystallography. The molecule is virtually planar, the dihedral angle between the dihydroquinoline nucleus and the 3-thiocarbamoyl-3-cyanopropylidene group being 3.39°. The bond lengths found indicate considerable transfer of charge between the dihydroquinoline ring and the cyanothioacetamide group. The crystal contains stacks of molecules with an interplanar spacing of 3.351 Å, which could also facilitate charge transfer.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 896–902, April, 1991.     

X-ray diffraction and spectral studies of 1-phenyl-3-methyl-4-(2′,4′-Dimethylphenylazo)-pyrazolone-5

The molecular and crystal structures of 1-phenyl-3-methyl-4-(2,4-dimethyl-phenylazo) pyrazolone-5 were determined. In the crystal the molecule exists as the hydrazone tautomer. The pyrazole ring is planar, and the substituents are practically coplanar with it. The molecule contains an intramolecular NH...O hydrogen bond that closes a practically planar six-membered ring (N...O, 2.77 (I), H...O 2.14 Å, angle at H(N(4)) hydrogen 131 °). The x-ray diffraction data agree with the spectral data and with the CNO calculation.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 816–821, June, 1985.     

Hydrogen bond in 3-acetyl-4-hydroxycoumarin: X-ray diffraction study and quantum-chemical calculations

The proton transfer and the character of the strong intramolecular O--H...O hydrogen bond (O...O 2.442 ) in 3-acetyl-4-hydroxycoumarin were analyzed based on the results of X-ray diffraction study in the temperature range from 100 to 353 K and quantum-chemical B3LYP/6-31G(d,p) calculations. The barrier to proton transfer along the H-bond line is low (2 kcal mol^–1). However, no proton transfer was observed in the crystal at 100 K. Bader's topological analysis of the electron density distribution both in the crystal and in the isolated molecule demonstrated that the hydrogen bond corresponds to an intermediate type of interatomic interactions (E(r) < 0, ²(r) > 0 at the critical point (3, –1)).     

Crystal and molecular structures of the γ-sultones of 1-(3-oxy-4-homoadamantyl)propane-1-sulfonic and 1-(3-oxy-4-homoadamantyl)butane-1-sulfonic acids

A study was carried out on the crystal and molecular structures of the -sultones of 1-(3-oxy-4-homo-adamantyl)propane-1-sulfonicand 1-(3-oxy-4-homoadamantyl)butane-1-sulfonicacids. The configurations of these molecules were established. Contact conformerism of the five-membered rings (C4 and C12 envelopes) is observed at the carbon atom of the sultone ring independently of the length of the alkyl substituent.M. V. Lomonosov Moscow State University. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 6, pp. 85–91, November–December, 1989.     

Some symmetry aspects of layered-clathrate structures formed by Ni (NCS)2 (4-methylpuridine)4

The crystal structures of layered clathrate inclusion compounds of Ni(CNS)₂ (4-methylpyridine)₄ with 1-bromonaphthalene (I) and azulene (II) were analyzed by x-ray single-crystal diffractometry [crystal data: I–C₄₆H₄₂N₆S₂Br₂Ni; a=11.88(1), b=11.82(1), c=32.79(3), =102.0(1), Z=4, P2₁/c; II–C₄₆H₄₄N₆S₂Ni; a=11.51(2), b=11.64(1), c=32.98(2), =103.4, Z=4, P2₁/n]. Disordering of guest molecules in I is concluded, based on x-ray study, and positions of the guest (each of the two symmetry independent molecules disordered over two orientations) have been refined. In II disoder of guest-azulene is also observed but only one from the two symmetrically independent guest molecules could be located from the x-ray data. The empirical force field calculations were performed for I and II. The results were used for location of the second azulene molecule and for discussion of the disorder mole (short or long-range).     

4-hydroxy-2H-1,2-benzothiazine-3-carbohydrazide 1,1-dioxide-oxalohydrazide (1:1): X-ray structure and DFT calculations

The title compound, 4-hydroxy-2H-1,2-benzothiazine-3-carbohydrazide 1,1-dioxide-oxalohydrazide (1:1), is determined using X-ray diffraction techniques and the molecular structure is also optimized at the B3LYP/6-31G(d,p) level using density functional theory (DFT). The asymmetric unit consists of four independent molecules. The oxalohydrazide molecules have the centre of symmetry at the mid-point of the central C-C bond. Each thiazine ring adopts a half-chair conformation. Intermolecular C-H...O, N-H...O and N-H...N hydrogen bonds produce R ₂ ² (10), R ₂ ² (13), R ₃ ³ (12) and R ₃ ³ (15) rings, which lead to one-dimensional polymeric chains. An extensive three-dimensional supramolecular network of N-H...N, N-H...O, C-H...O and O-H...O hydrogen bonds is responsible for crystal structure stabilization.     

Synthesis and structure of 4-[(4-Nitro-1,2,5-oxadiazol-3-yl)-NNO-azoxyl]-1, 2,5-oxadiazol-3-amine

The synthesis of the energetic compound 4-[(4-nitro-1,2,5-oxadiazol-3-yl)-NNO-azoxyl]-1,2,5-oxadiazol-3-amine (3) was achieved in two steps from diaminofurazan (1). Compound 3 was characterized by X-ray diffraction. From the X-ray structure a bifurcated intramolecular H bond between O(2)-H(2)-N(4) was observed. In addition, intramolecular H bonding was observed between H(1) and N(7) of an adjacent molecule. One molecule of ethanol and one-half molecule of water per molecule of3 was observed in the crystal lattice. However, no H bonding was observed between the solvent molecules and3 in the crystal lattice. Despite the presence of solvent in the crystal lattice,3 was found to have a high crystal density (d=1.856 g/cm³).     

Absence of the Nitrone Form among the Refined Crystal Structures of 1-Methoxy- and 1-(2-Chloro-ethyl)oxy-2-hydroximino-3-methyl-4-nitro-3-phospholene-1-oxides

Crystal structure refinement has been performed by XRD for 1-methoxy- and 1-(2-chloroethyl)oxy-2-hydroximino-3-methyl-4-nitro-3-phospholene-1-oxides (I) C₆H₉N₂O₅P, Z=8, space group P2₁/c, and (II) C₇H₁₀ClN₂O₅P, Z=4, space group P2₁/c. Disordering of independent molecules I and I' in the crystal structure of I and of molecule II in the crystal structure of II has been found. Full-matrix least-squares refinement of I and II was performed anisotropically (isotropically for H) to R=0.052 (I) and 0.034 (II) for all 4377 (I) and 2533 (II) independent reflections (CAD-4 automatic diffractometer, MoK). The authors of the first XRD analysis of crystals I and II made the wrong conclusion that compounds I and II exist in crystal in NH-nitrone form; i.e., that they contain an ON(H)=C nitrone isomer group instead of an H–O–N=C oxime group. As shown in this study, compounds I and II exist in ordinary oxime form. The authors of the first XRD analysis failed to notice the disordering of molecules I, I', and II, and they erroneously took the second, low-occupied oxygen sites of the disordered oxime groups for the H atoms at N atoms.     

外型-1,4-氧桥-环己基-2,3-二羧酸的晶体及分子结构

外型-1,4-氧桥-环己基-2,3-二羧酸晶体属单斜晶系,空间群为P2_1/n;晶胞参数为:α=5.594(3)A,b=11.178(7)A,c=14.675(11)A,β=91.46(5)°;Ζ=4.从直接法得到结构的初始模型,经块矩阵最小二乘修正后,最后的R值为0.072.在晶体中,分子间的O—H…O氢键将分子连接成层型氢键体系.使用自编的CNDO/2程序,计算得电子的能量、分子的总能量、偶极矩及各原子的电荷密度和净电荷.     

Pseudosymmetry in the crystal structure of 2,6-dimethyl-3,5-dicarbomethoxy-4-(2′,3′-dichlorophenyl)-1,4-dihydropyridine

Within the framework of a detailed crystallochemical analysis a comparison of the structures of symmetrically independent molecules was performed and the energy of intermolecular interaction was calculated for a triclinic bisystem crystal, 2,6-dimethyl-3,5-dicarbomethoxy-4-(2′,3′-dichlorophenyl)-1,4-dihydropyridine. Pseudosymmetrical operations were detected and identified. The presence of highly efficient layers with pseudomonoclinic symmetry was disclosed in this structure.     

Molecular and crystal structures and chemical properties of 2,6-dim ethyl-4-phenyl-3,5-diethoxycarbonyl-1, 4-dihydropyridine

The molecular and crystal structures of 2,6-dimethyl-4-phenyl-3,5-diethoxycarbonyl-1,4-dihydropyridine were determined by x-ray diffraction analysis. The following crystallographic data were obtained: a=9.754(2), b = 7.401(1), c=24.384(5) Å, =92.61(2)°, Z=4, d_calc= 1.24 g-cm^–3, space group P2₁/c. The structure was decoded from 1531 reflections, the intensities of which were measured with a P2₁ automatic diffractometer and refined by the method of least squares within the total matrix anisotropic approximation to R=0.061. The dihydropyridine ring has a boat conformation. Packing of the molecules in the crystal is realized at the van der Waals distances and is stabilized by an N₁- H ... O₁₅ hydrogen bond (2.98 Å). From the data on the geometry of the molecule, the compound is closer to aminovinylcarbonyl compounds, whereas according to the data on the conformation, it is closer to Meisenheimer compounds than to pyridine derivatives. The C=O bond length corresponds to its length in esters and acid amides, despite the exceptionally low reactivity of this group in 3,5-dicarbonyl-1,4-dihydropyridines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1229–1234, September, 1977.     

Synthesis,crystal structure and molecular docking studies of novel 2-(4-(4-substitutedphenylsulfonyl)piperazin-1-yl)quinolone-3-carbaldehyde derivatives

The present work reports the synthesis of novel 2-(4-(4-substitutedphenylsulfonyl) piperazin-1-yl) quinolone-3-carbaldehyde derivatives, namely, 2-(4-tosylpiperazin-1-yl)quinoline-3-carbaldehyde (4a), 2-(4-(4-nitrophenylsulfonyl)piperazin-1-yl)quinoline-3-carbaldehyde (4b) and 2-(4-(4-tert-butylphenylsulfonyl) piperazin-1-yl)quinoline-3-carbaldehyde (4c). These compounds have been characterized by FT-IR, ¹H-NMR, ¹³C-NMR and LCMS. Further, the structures of compounds 4b and 4c have been elucidated by single crystal X-ray diffraction studies. The asymmetric unit of 4b contains two molecules (A and B) and that of 4c contains one. The piperazine ring in both the molecules 4b and 4c has chair conformation and the aldehyde group is twisted with respect to the quinoline group, respectively, by 13.3 (3)°, 18.2 (3)° and 11.2 (3)° in Molecule A & B of 4b and 4c due to the bulky piperazinyl group present in the ortho position. The crystal structures of both features interactions of the type C-H…O, C-H…π_aryl and π_aryl… π_aryl, leading to a three-dimensional (3D) supramolecular architecture in 4b and a one-dimensional (1D) architecture in 4c. The various intermolecular interactions exhibited in 4b and 4c are well supported by Hirshfeld surface and fingerprint plots analysis. Further, the three compounds were evaluated for their in-silico antimicrobial activity. In-silico molecular docking studies were carried out in order to know the binding modes of the synthesized compounds with DNA Gyrase A and N-myristoyltranferase as target proteins for antibacterial and antifungal docking studies, respectively.     

2-[3-Phenyl-5-(m-Chlorophenyl)-2-Pyrazolin-1-yl]-3-Methyl-4(3H)-Quinazolinone

There are two molecules in the asymmetric unit (I and II). The structure consists of a 2-pyrazoline ring and three aromatic rings two of which are free and the third one is condensed with a 3-methyl-4(3H)-pyrimidine ring (4(3H)-Quinazolinone). While the pyrazoline ring is in the distorted envelope conformation, the free aromatic rings are planar and the pyrimidine ring deviates from the planarity. The crystal structure is stabilized by C–HO inter and intramolecular bonds.     

Preparation, Crystal Structure and Thermal Decomposition Character of [Ni(CHZ)3]SO4·3H2O

A new coordination compound [Ni(CHZ)₃]SO₄·3H₂O (CHZ=carbohydrazide) was synthesized and characterized by elemental analysis and fourier transform infrared (FTIR) spectra, and its crystal structure was determined by X-ray single crystal diffraction. The crystal belonged to the triclinic system, space group with a=0.85237(1) nm, b=0.90964(1) nm, c=1.22559(2) nm, β=96.731(2)°, V=0.8849(2) nm³, Z=2, D_c=1.798 g·cm⁻³. In the asymmetric unit, three carbohydrazide (CHZ) bidentate ligands were coordinated with a Ni(II) cation by carbonyl O atoms and terminal N atoms of the hydrazine groups to form three planar chelate rings which were vertical to one another. Ni(II) cations, CHZ ligand molecules, sulfate anions, and lattice water molecules were jointed to a complicated three-dimensional network structure through coordination bonds, electrostatic forces and extensive hydrogen bonds. Natural bond orbital (NBO) atomic charges of CHZ were obtained from the density functional theory (DFT) method at the B3LYP/6-311+G^** level to interpret the reason why the coordination sites in carbohydrazide molecule were the oxygen atom of the carbonyl group and terminal N atoms of the hydrazine group. The thermal decomposition mechanism was tested through differential scanning calorimetry (DSC), thermogravimetric analyses, and Fourier transform infrared spectra. The kinetic parameters of the two exothermic processes of the title compound were studied applying the Kissinger's and Ozawa-Doyle's methods. The results indicated that the title complex possessed high energy and good thermal stability.     

X-ray crystallographic and quantum-chemical investigation of tert-butyl hydroperoxide

An MNDO calculation and an x-ray crystallographic investigation of tert-butyl hydroperoxide (I) were undertaken. The two symmetrically independent molecules of (I), which in fact have identical geometric parameters, form infinite chains along the y axis through staggered hydrogen bonds. The chains have local symmetry, described by a noncrystallographic slip plane. The difference between the experimental value of the COOH dihedral angle (average 100°) and the calculated value (128.5°) is most likely due to the formation of intermolecular hydrogen bonds in the crystal, the energies of which (30 kJ/mole) are considerably larger than the calculated excess energy of the conformers observed in the crystal (3.4 and 1.9 kJ/ mole).Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 1, pp. 82–87, January–February, 1989.     

Twelve-membered crown ethers: Crystal structures of benzo-12-crown-4 and naphtho-12-crown-4

The crystal structures of two 12-membered crown ethers, benzo-12-crown-4 (1) and naphtho-12-crown-4 (2), have been determined by X-ray analysis. Both structures are molecular. Compound1 is monoclonic,P2₁/b,a=8.466(3),b=8.019(3),c=33.590(10) Å, =90.99(3)^o. The unit cell contains two crystallographically independent molecules of1 with similar conformations. Compound2 is also monoclinic,P2₁/a,a=24.148(8),b=14.535(4),c=7.987(5) Å, =102.87(2)^o. Two independent molecules in the unit cell have significantly different conformations. Supplementary data relating to this publication have been deposited with the British Library as Supplementary Publication No. SUP 82145 (19 pages).     

Structural and bonding investigation of the donor—acceptor complex 1-Sn(phenanthroline)-2, 3-[Si(CH3)]3]2-2,3-C2B4H4: A comparative study of the group 14 metallacarborane-Lewis base complexes

Closo-1-Sn-2,3-[Si(CH₃)₃]₂-2,3-C₂B₄H₄ (1) reacts with 1,10-phenanthroline to form the complex 1-(C₁₂H₈N₂)Sn-2, 3-[Si(CH₃)₃]₂-2,3-C₂B₄H₄. When crystals of this complex were grown slowly from benzene, a crystalline modification (2) was obtained in which the unit cell consisted of four identical molecules of the base-stannacarborane and six benzene molecules of solvation. When the complex was sublimed, a second crystalline modification (3) was obtained whose unit cell consisted of two crystaliographically different molecules (3-1 and3-2). In all three forms the tin was not symmetrically bonded to the carborane but was slipped toward the boron side of the C₂B₃ face, and the phenanthroline molecules were oriented opposite to the cage carbons so that the plane of the base and the carborane faces gave acute dihedral angles. However, the three forms showed a great deal of variation in the extent of slippage and the magnitudes of the base-carborane dihedral angles. Since these distortions are common structural features of base-group 14-carborane and cyclopentadienyl systems, MNDO-SCF molecular orbital calculations were carried out on the model compounds 1-(C₁₂H₈N₂)Sn-2,3-C₂B₄H₆, 1-[C₁₀H₈N₂)Sn-2, 3-C₂B₉H₁₁, and [(C₁₀H₈N₂)-SnC₅(CH₃)₅]⁺ to determine what factors dictate the structures of these complexes. The results showed that competing bonding interactions give rise to a very broad minimum in energy as a function of slippage and base orientation. Small energy variations, such as those produced by crystal packing forces, could produce large structural changes. Complex2 crystallizes in the monoclinic space group P2₁/n witha=11.096 (9) Å,b=26.51(2) Å,c=11.729 (7) Å,=107.43 (6) ,U=3291 (4) ų, andZ=4. Full-matrix least-squares analysis converged atR=0.044 andR _w=0.055. Complex3 crystallizes in the triclinic space group P¯1 witha=10.251 (3) Å,b= 13.845(9) Å;c=19.168 (9) Å,=71.12 (5) ,=89.29 (3) ,=84.62 (4) ,U=2562 (2) ų, andZ=4. The structure refined atR=0.079 andR _w=0.125.     

Crystal and Molecular Structure of 5-Acetylamino-3-nitro-1,2,4-triazole

This paper reports on an X-ray diffraction study of 5-acetylamino-3-nitro-1,2,4-triazole. Monoclinic crystals, space group P2_1/c; a=8.2079(7), b=13.096(1), c=13.650(1) , =100.64(1)°. Two independent molecules are identical in conformation and both have an N–H···sO intramolecular hydrogen bond; the difference lies in their interactions with neighbors. In molecule A, the acetyl oxygen atom and all nitrogen atoms (except those of the amino group) are involved in the intermolecular hydrogen bonds; in molecule B, these hydrogen bonds are formed by only two NH groups in addition to the above oxygen. The crystal structure of the title compound is compared with that of 5-amino-3-nitro-1,2,4-triazole.     

High-pressure freezing, crystal structure studies and SiCF3 bond polarizability of trimethyl(trifluoromethyl)silane

Trimethyl(trifluoromethyl)silane, (CH₃)₃SiCF₃, has been in situ pressure frozen in a diamond anvil cell and its structure determined at 0.90(5) GPa/296 K by single-crystal X-ray diffraction. The crystal is monoclinic, space group P2₁/m, with the molecules lying on crystallographic mirror planes. The CH₃ and CF₃ groups assume the fully staggered conformation. The 14-fold coordination scheme of the molecules is similar to those in (CH₃)₃SiCl polymorphs, but different from that in crystalline tetramethylsilane, (CH₃)₄Si (TMS). The longest SiC bond length of 1.943(12) Å observed in the crystal structure has been documented. The shortest intermolecular contacts in the structure of pressure-frozen CF₃Si(CH₃)₃ are observed between the hydrogen atoms, and those involving fluorine atoms are longer than sums of van der Waals’ radii. These structural features explain the facile cleavage of SiCF₃ bond for CF₃ group transfer in organic reactions.