Hydrogen bonds and π–π stacking interaction in 4′, 7-dimethoxylisoflavone and 4′,7-diacetyl-O-isoflavone

4′,7-dimethoxylisoflavone, C₁₇H₁₄O₄, (I), is linked into a supramolecular structure by a variety of weak but direction-specific intermolecular forces, the molecules are linked into chains through C–H⋅sO hydrogen bonds, these chains are further linked by face-to-face (F-tape) π–π stacking into a one-dimensional bi-chain, another type π–π stacking, edge-to-face (T-tape), assemble the bi-chain into framework together with C–H⋅sO hydrogen bonds. 4′,7-diacetyl-O-isoflavone, C₁₉H₁₅O₆, (II), shows some discrepancies with I and the molecules are assembled into framework all by C–H⋅sO hydrogen bonds. The molecules are linked into centrosymmetric dimers built from classic R₂² (8) rings by pairs of C–H⋅sO hydrogen bonds, the dimers are linked into (011) sheets by combination of the R₂² (8) ring and C–H⋅sO hydrogen bonds, another C–H⋅sO hydrogen bond assemble the sheets into three-dimensional network.     

X-ray diffraction study of 2,2′,4,4′,6,8,8′,10,10′,12-decamethylbicyclo[5.5.1]hexasiloxane and 2,2′,4,4′,6,8,8′,10,10′,12-decamethylbicyclo[5.5.1]-9-carbahexasiloxane

The crystal structures of two organosilicon compounds are studied by X-ray diffraction at 200 K. Crystals of 2,2′,4,4′,6,8,8′,10,10′,12-decamethylbicyclo[5.5.1]hexasiloxane (C₁₀H₃₀O₇Si₆) are monoclinic, a = 12.260(1) Å, b = 11.716(1) Å, c = 32.169(2) Å, β = 92.802(2)°, space group C2/c, Z = 8, wR2 = 0.132, and R1 = 0.053 for 3989 reflections with F > 4σ(F). Crystals of 2,2′,4,4′,6,8,8′,10,10′, 12-decamethylbicyclo[5.5.1]-9-carbahexasiloxane (C₁₁H₃₂O₆Si₆) are triclinic, a = 10.709(1) Å, b = 11.046(1) Å, c = 12.111(1) Å, α = 117.059(1)°, β = 95.566(1)°, γ = 108.088(1)°, space group $P\bar 1$ , Z = 2, wR2 = 0.115, and R1 = 0.048 for 3948 reflections with F > 4σ(F). It is found that the substitution of the methylene group for the oxygen atom is accompanied by a minor conformational change in the bicyclic fragment and the SiCSi angle changes from the tetrahedral angle to 121.0(1)°. The high variability of the SiOSi bond angles is confirmed.     

7-Hydroxy-2-(2,3,4-trimethoxyphenyl)-4H-1-benzopyran-4-one: (7-hydroxy-2′,3′,4′-trimethoxyflavone)

7-Hydroxy-2,3,4-trimethoxyflavone, (C₁₈H₁₆O₆),M _r =328.32 crystallizes in the orthorhombic system, space groupPbna, with the following crystal data:a=8.853(2),b=12.870(2),c=26.293(3)Å,V=2996(1)ų,Z=8, MoK, =0.67 cm^–1,D _c =1.454 g·cm^–3,F(000)=1376,T=294K. The structure was solved by direct-methods and has been refined by full-matrix least-squares methods to a finalR value (F>(F)) of 0.0496. The molecule is not planar, the dihedral angle between the phenyl ring and the fused ring system is 27.3°. There are no intramolecular hydrogen bonds, but intermolecular short hydrogen contacts exist between hydroxyl hydrogen and carbonyl oxygen atoms.     

Crystal and molecular structure of 2′,4′-dimethoxyflavone

C₁₇H₁₄O₄,M _r =282.3, triclinic,P-1,a=8.469(3),b=8.516(2),c=20.425(8)Å,=84.95(3),=81.98(3), =70.47(2)°,V=1373(13)ų,Z=4,D _x =1.365 g cm^–3, (MoK )=0.71069 Å,=0.91 cm^–1,F(000)=592,T=294K,R=0.038 for 3577 observed reflections (F>3 (F)). The asymmetric unit is composed of two molecules. These two molecules, which are in planar conformations, differ in 4-methoxyl group orientation. Short intramolecular contacts are found between the -benzopyran portion and the dimethoxyphenyl ring.     

X-ray structure of 3′,4-dimethylthio-3,4′-diquinolinyl sulfide

The title compound (C₂₀H₁₆N₂S₃) is monoclinic, witha=31.550(9),b=8.504(3),c=14.745(3) Å,=114.14(3)°,Z=8 and space groupC2/c. The structure was solved by direct methods and refined toR=0.038 for 3012 reflections. The molecule exists in an uncommon conformation. Two quinoline moieties are nearly perpendicular to each other (80.9(3)°). Both methylthio groups have different orientation (the 4-SCH₃ group is nearly perpendicular and the 3-SCH₃ is nearly coplanar to the quinoline moieties). Two pairs of sulfur atoms in ortho-positions remain in very close contact. The conformation of the molecule explains an unusual¹H NMR spectrum.Part XVI in the series of Azinyl Sulfides.     

X-ray diffraction investigation of trans-2,8-dihydroxy-2,8-diphenyl-4,4′,6,6′,10,10′, 12,12′-octamethylcyclohexasiloxane and trans-2,8-dihydroxy-2,4,4′,6,6′,8,10,10′, 12,12′-decamethyl-5-carbahexacyclosiloxane

The crystal structures of two organosilicon compounds are studied by X-ray diffraction. Crystals of trans-2,8-dihydroxy-2,8-diphenyl-4,4′,6,6′,10,10′,12,12′-octamethylcyclohexasiloxane, C₂₀H₃₆O₈Si₆, (I) are triclinic; at 110 K, a = 11.476(1) Å, b = 12.106(1) Å, c = 13.636(1) Å, α = 94.337(1)°, β = 112.669(1)°, γ = 112.216(1)°, space group $P\bar 1$ , Z = 2, and R = 0.057 for 5069 reflections with F > 4σ(F). Crystals of trans-2,8-dihydroxy-2,4,4′,6,6′,8,10,10′,12,12′-decamethyl-5-carbahexacyclosiloxane, C₁₁H₃₄O₇ Si₆, (II) are tetragonal; at 293 K, a = b = 15.487(3) Å, c = 11.364(3) Å, space group P4₂/n, Z = 4, and R = 0.055 for 955 reflections with F > 4σ (F). It is found that the structure of compound I, in which the substituents at the Si(1) atom differ in volume and inductive effect, contains two crystallographically independent molecules with different conformations of the hexasiloxane ring. In structure II, the oxygen atom and the methylene group are statistically disordered as a result of the location of the molecule at the center of symmetry. Although the SiCSi angle [122.1(1)°] differs noticeably from the tetrahedral angle, its value is characteristic of cyclohexasiloxanes and is not related to the disorder.     

Synthesis and Structural Characterization of (2,4-Diamino-5-(3′,4′,5′-Trimethoxybenzyl)Pyrimidine Copper (II)) Complex

Abstract  The reaction of Cu(OOCCH₃)₂·H₂O with (2,4-diamino-5-(3′,4′,5′-trimethoxybenzyl) pyrimidine (trimethoprim) in ethanolic solution at 80 °C affords the title complex which has been characterized by elemental, IR, and NMR (¹H and ¹³C).The crystal structure has been determined by single crystal X-ray diffraction. Compound 1 (C₃₆H₄₈Cu₂N₈O₁₄) is triclinic, space group P-1 with a = 7.2676(4) ?, b = 11.6721(7) ?, c = 12.8279(8) ?, α = 95.839(1)°, β = 93.456(1)°, γ = 105.541(1)°, Z = 1. Two copper atoms are coordinated directly to each other as well as are held together by four bridging aceto groups. Each copper atom is also bonded opposite the Cu–Cu vector to a trimethoprim molecule through the N(1) atom of the pyrimidine ring. Trimethoprim acts as a monodentate ligand through the pyrimidine nitrogen N(1) atom. The complex was screened for the activity against several bacteria, showing more activity against bacteria as compared to trimethoprim. Graphical Abstract  To enhance the activity of trimethoprim, its derivative was prepared and there bacterial activity against several bacteria was analyzed.      

Synthesis and structure of 5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-di(methylthio)-3,3′-biisoquinoline

Title compound, C₂₀H₂₄N₂S₂, crystallizes in the orthorhombic system, space group Pbca, with cell constants a = 5.1968(5) Å, b = 15.6692(11) Å, c = 22.3881(11) Å , Z = 4, T = 293 K, D_cal = 1.299 g cm^–3. The structure was solved by direct methods and refined to R value of 0.0465 for 1566 reflections. Two methylthio-octahydroisoquinoline parts of molecule are related by the center of symmetry and possess the trans conformation. This conformation is more energetically stable than cis but the molecule can rotate about the C(6)–C(6) central bond at room temperature (molecular mechanics calculations). There is a short intramolecular contact C(5)–H(51) N(1) in the molecule. The molecules in the crystal form molecular layers parallel to (001) crystallographic plane and the molecular packing is determined by the van der Waals forces only.     

Crystal Structure of 3-Hydroxy-3′,4′-Methylenedioxy Flavone-6-Carboxylic Acid Dimethylformamide Solvate

Abstract  

The optically pure 3-hydroxy-3′,4′-methylenedioxy flavone-6-carboxylic acid was obtained through the chalcone route. The structure of 3-hydroxy-3′,4′-methylenedioxy flavone-6-carboxylic acid was first elucidated by single crystal X-ray analysis: triclinic, space group, triclinic (P-1) with a = 8.1379(13) ?, b = 8.9831(14) ?, c = 13.198(2) ?, α = 88.413(2)°, β = 74.908(2)°, γ = 72.987(2)°. V = 889.5(2) ?³, Z = 2. The structure was solved by direct methods and refined to a final R = 0.0413 for 1630 reflections with I > 2σ(I). The crystal structure is stabilized by O–H···O and C–H···O hydrogen bondings and π–π stacking interactions.     

4′-(4-(4-羧基苯氧基)苯基-4,2′6′,4″-三联吡啶的 合成、晶体结构及性质研究

以4-乙酰基吡啶及对氯苯甲醛为原料合成了一例新的化合物4′-(4-(4-羧基苯氧基)苯基-4,2′6′,4″-三联吡啶,用元素分析、红外光谱、紫外光谱、X射线单晶衍射对此化合物进行了表征,结果表明,该化合物属于P2(1)/c空间群,晶胞参数为:a=1.4405(5)nm,b=0.7708(2)nm,c=2.0567(7)nm,β=107.699(6)°.     

Crystal and molecular structure of chloramphenicol analog: 2-amino-4-methoxy-2′,2′-dichloroacetophenone

The crystal and molecular structure of the title compound has been determined from diffractometric data usingMo K radiation. The crystals are orthorhombic, space groupP2₁2₁2₁, witha=12.052(3),b=11.901(2),c=6.976(1) Å andZ=4. The structure was solved by the heavy-atom method and refined by full-matrix least-squares to a finalR value of 0.039 with 1096 observed reflections. The molecule is is almost planar. The acetyl group and the phenyl ring are strongly conjugated, the corresponding dihedral angle being 3.3(2)°. The structure is stabilized by an intramolecular N(1)-H(N)1O(l) hydrogen bond.     

Crystal structure of 2,2,3-trimethyl-3-(2′,4′,5′-tricyanophenyl) cyclopentyl-1-acetic acid, methyl ester, C20H21N3O2

The title compound crystallizes in space group P2₁/n, with a = 14.600(2), b = 7.091(2), c = 18.211(5) Å, and = 103.67(2)°. Owing to the centric space group, both C(1) and C(3) chiral centers are either R or S. The acetate group is equatorial, the H(1) and the methyl group at C(3) are axial and reciprocally trans.     

A novel class of naturally occurring halogenated pyrroles, 1,1′-dimethyl-3,3′,4,4′,5,5′-hexabromo-2,2′-bipyrrole, 5,5′-dichloro-1,1′-dimethyl-3,3′,4,4′-tetrabromo-2,2′-bipyrrole, and 1,1′-dimethyl-3,3′,4,4′,5,5′-hexachloro-2,2′-bipyrrole

Crystal structure determinations of the three title hexahalogenated bipyrroles, (I) C₁₀H₆Br₆N₂, (II) C₁₀H₆Br₄Cl₂N₂, and (III) C₁₀H₆Cl₆N₂, reveal essentially planar pyrrole rings having dihedral angles of 64.7, 65.1, and 64.2° between the least-squares planes, favoring in each case a closer methyl–halogen conformation. All three complexes crystallize in the orthorhombic space group Pbcn with the following cell dimensions: (I) a = 12.654(3) Å, b = 8.853(2) Å, c = 13.753(3) Å, = = = 90°, Z = 4; (II) a = 12.438(6) Å, b = 8.753(6) Å, c = 13.696(3) Å, = = = 90°, Z = 4; (III) a = 12.088(6) Å, b = 8.566(4) Å, c = 13.486(8) Å, = = = 90°, Z = 4.     

Bis(2,6-(2′,6′-diisoproylanil)diformyl-4-chloro-phenolate) nickel(II)

Bis(2,6-(2,6-diisoproylanil)diformyl-4-chloro-phenolate) nickel(II) was prepared by the reaction of 2,6-(2,6-diisoproylanil)diformyl-4-chloro-phenol with nickel chloride. The title complex crystallized in P2₁/c, with cell dimensions a = 9.962(2) Å, b = 12.087(3) Å, c = 24.445(6) Å, and = 97.032(5), giving a volume of 2921.4(13) ų. The bis(2,6-(2,6-diisoproylanil)diformyl-4-chloro-phenolate) nickel(II) adapts an ideal parallelogram, in which the Ni atom is coordinated with two phenolic oxygen atoms [O(1), O(1A)] and two imino nitrogen atoms [N(1), N(1A)].     

Synthesis of (2,4-Diamino-5-(3′,4′,5′-trimethoxybenzyl) Pyrimidine) Copper (II) Complex at 20–25 °C and its Structural Characterization

Abstract  The title copper (II) complex with Trimethoprim was prepared at 20–25 °C and its crystal structure was determined by single crystal X-ray diffraction. Compound (C₃₆H₅₀Cu₃N₈O₁₆) is triclinic, space group P-1 with a = 6.4642(5) ?, b = 12.5495(9) ?, c = 13.4911(10) ?, α = 77.518(1)°, β = 85.326(1)°, γ = 84.413(2)°, Z = 1. In this compound, three copper atoms are bonded to each other, two terminal coppers are bonded to three oxygen atoms and N₁ of pyrimidine ring of Trimethoprim and central copper is bonded to four oxygen atoms. The amino nitrogen atoms are not involved in the coordination to the metal. Graphical Abstract  To enhance the activity of trimethoprim, its derivative was prepared and there bacterial activity against several bacteria was analyzed.      

The structure of Wallach's compound. Single-crystal X-ray structure determination oftrans-2,5-bis(trichloromethyl)-N-(1′-hydroxy-2′,2′,2′-trichloroethyl)-4-imino-1,3-dioxolane

The structure of Wallach's compound, C₇H₄O₃NCl₉, prepared in 1874 from concentrated aqueous solutions of potassium cyanide and chloral hydrate, has long been undecided. By single crystal X-ray crystallography it has now been established astrans-2,5-bis(trichloromethyl)-N-(1-hydroxy-2,2,2-trichloroethyl)-4-imino-1,3-dioxolane, confirming the tentative assignment by¹H and¹³C NMR spectrography. The title compound is monoclinic,P2₁/c;a=8.445 (1),b=10.948(1),c=17.923(4) Å;=94.36(1)°;Z=4. The structure was solved by direct methods, from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer, and refined by least squares to a finalR value of 0.041 using 2101 reflections.     

X-ray crystal and molecular structure of 2,3-dideoxy-4-thio-d-arabino-heptonic acid 1,4-lactone: a key intermediate for syntheses of 2′, 3′-dideoxy-4′-thio-l-nucleosides

The structure of 2,3-dideoxy-4-thio-d-arabino-heptonic acid 1,4-lactone has been determined by X-ray diffraction. Crystals of the compound are orthorhombic, space groupP2₁2₁2₁, with cell dimensionsa=11.555(5),b=10.451(5),c=9.604(5) Å, andZ=4. The diffraction experiment has allowed to assign the absolute configuration (4R, 5R, 6R) to the chiral centers of the molecule.     

Crystal structure of 4-phenyl-3,5-dioxacyclohexyl-1, 1′-cyclopentane-2′,3″-(1,5,8,11-tetraoxacyclotridecane)

The structure of the title compound is determined by X-ray diffraction (DAR-UMB diffractometer, θ-θ/2θ scan mode, MoK _α radiation, direct method). The crystal is monoclinic, a = 24.582(6) Å, b = 22.812(8) Å, c = 8.647(3) Å, γ = 60.64(2)°, ρ _calcd = 1.232 g/cm³ space group A2/a, and Z = 8 for C₂₂H₃₂O₆. The molecule consists of four fragments: 13-crown-4 (A), 1,3-dioxane (B), a five-membered ring (C) acting as a bridge between fragments A and B, and a phenyl ring (D). Introduction of the bulky ring C as a bridge into the molecule results in significant deviations (up to ±0.014 Å) of the ether O atoms from planarity. The conformation of the macrocyclic fragment is [3433] according to the Dale notation. The C—H?O 1,4-interactions, which are energetically favorable occur in the propylene part of 13-crown-4: the C(2)?O(5) and C(4)?O(1) distances are 2.82 Å. The molecules in the structure form planar networks parallel to the xy plane. The intermolecular contacts correspond to the van der Waals interactions.     

Crystal and molecular structure of CI Solvent Yellow 18, 4-(2′,4′-dimethyl phenyl hydrazono)-5-methyl-2-phenyl-3H-pyrazol-3-one

The crystal structure of CI Solvent Yellow 18, C₁₈H₁₈N₄O, has been determined by single crystal X-ray diffraction techniques. It crystallizes in the monoclinic system witha=7.480(2) Å,b=19.184(3) Å,c=11.260(1) Å,=98.00(3)°, space groupP2₁/n andZ=4. The structure has been solved by direct methods, and least-squares refinement has been completed on three-dimensional data (2310 reflections, CuK radiation). The hydrogen atoms have been found, but only their positional parameters refined. Final residual 0.085 (all positive intensity data). The molecule exists as the hydrazone tautomer and intramolecular hydrogen bonding keep the molecule approximately planar. The molecules are packed in layers parallel to the (¯202) plane and in columns parallel tob. Alternate molecules within the columns are in antiparallel. The molecules are linked by van der Waals' forces.     

Crystal structure ofβ-C.I. Solvent Yellow 18, 4(2′,4′-dimethylphenyl hydrazono)-5-methyl-2-phenyl-3H-pyrazol-3-one

The crystal structure of-C.I. Solvent Yellow 18, C₁₈H₁₈N₄O, has been determined by single crystal X-ray diffraction techniques. It crystallizes in the monoclinic system witha=30.948(18)Å,b=4.918(4)Å,c=20.861(9)Å,=91.68(4)°, space groupC2/c,Z=8. The structure has been solved by direct methods and least-squares refinement has been completed on three dimensional data (1237 reflections MoK radiation). The hydrogen atoms have been found but only their positional parameters refined. Final residual 0.092 (all intensity data). The molecule exists as the hydrazone tautomer and intramolecular hydrogen bonding keeps the molecule approximately planar. The molecules are packed in columns parallel to theb axis, while the molecule lies approximately parallel to the (51¯3) plane. The molecules are linked by van der Waals' force.