Synthesis,Characterization, and Crystal Structure of <Emphasis Type="Italic">N</Emphasis>-<Emphasis Type="Italic">p</Emphasis>-Bromophenyl-<Emphasis Type="Italic">N</Emphasis>′-Phenylacetylthiourea

Abstract   N-p-bromophenyl-N′-phenylacetylthiourea was characterized by elemental analysis, IR and ¹H NMR etc. Single crystal structure of the title compound was determined on X-ray diffraction instrument. The title compound crystallizes in monoclinic space group c2/c, with a = 21.442(5) ?, b = 12.208(2) ?, c = 11.955(2) ?, β = 109.375(4)°, and D _calc = 1.571 g/cm³ for Z = 8. An intermolecular hydrogen bond N–H···S which links two thiourea molecules as a dimer and an offset face-to-face π–π stacking interaction were observed in the title compound. The strong non-covalent interaction influences the conformation and property of thiourea derivatives. Index Abstract  The title compound, N-p-bromophenyl-N′-phenylacetylthiourea, was synthesized by the treatment of phenylacetyl chloride with 4-bromoaniline and its crystal structure determined. Single crystal X-ray diffraction analysis reveals that hydrogen bonds and face-to-face π–π stacking interactions have strong influence on the conformation and molecular stacking of the title compound.      

Synthesis and Crystal Structure of 4-Methyl-6H-pyrido[3,2,1-<Emphasis Type="Italic">jk</Emphasis>]carbazol-6-one

Abstract  The synthesis, NMR and X-ray structure of 4-methyl-6H-pyrido[3,2,1-jk]carbazol-6-one—a potential DNA intercalator are reported. The compound crystallizes in the orthorhombic Pbca space group with unit cell parameters: a = 7.775(8), b = 15.113(7), c = 19.849(7) ?, V = 2332.8(3) ?³, Mr = 233.26 and Z = 8. In the three-dimensional arrangement of the molecules no classical hydrogen bonds were found; weak π···π and C–H···O interactions are responsible for the packing of the molecules in the crystal structure. Index Abstract  In the three-dimensional arrangement of the title compound no classical hydrogen bonds were found; weak π···π and C–H···O interactions are responsible for the packing of the molecules in the crystal structure.      

Synthesis and Crystal Structure of 5-[2-(6-bromonaphthalenyloxymethyl)]-3-(4-morpholinomethyl)-1,3,4-oxadiazole-2(3<Emphasis Type="Italic">H</Emphasis>)-thione

Abstract  The title compound, C₁₈H₁₈BrN₃O₃S, a derivative of 1,3,4-oxadiazole, crystallizes in the triclinic space group P-1 with unit cell parameters a = 6.8731(3), b = 8.9994(4), c = 15.7099(6) ?, α = 92.779(3)°, β = 130.575(3)°, γ = 107.868(4)°, Z = 2. The dihedral angle between the mean planes of the planar naphthyl and morpholine (chair) rings with the planar oxadiazol ring is 50.1(8) and 76.8(6)°, respectively. The planar naphthyl ring is twisted 52.2(5)° with the mean plane of the morpholine ring. A group of four intermolecular close contacts are observed between a bromine atom and hydrogen atoms from the closely packed naphthyl, morpholine and oxy–methyl groups in the unit cell. These molecular interactions in concert with an additional series of π–π stacking interactions that occur between the center of gravity of the two 6-membered rings of the naphthalene group influence the twist angles of each of these three groups. A MOPAC AM1 calculation of the conformation energy of the crystal structure [226.0128(9) kcal] compared to that of the minimum energy structure after geometry optimization [29.9744(1) kcal] reveals a significantly reduced value. The twist angles of the three groups above also change after the AM1 calculation giving support to the influence of both intermolecular C–H···Br short-range interactions and Cg π–π stacking interactions on these angles which therefore play a role in stabilizing crystal packing. Graphical Abstract  Crystal structure of 5-{[(6-bromonaphthalen-2-yl)oxy]methyl}-3-(morpholin-4-ylmethyl)-1,3,4-oxadiazole-2(3H)-thione, C₁₈H₁₈BrN₃O₃S, is reported and its geometric and packing parameters described and compared to a MOPAC computational calculation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Supramolecular Network via Hydrogen Bonding and π–π Stacking in 4,4′-Bipyridin-1-ium Perchlorate Dihydrate

Abstract The crystal structure of 4,4′-bipyridin-1-ium perchlorate dihydrate, [C₁₀H₉N₂](ClO₄) · 2H₂O, is determined by room temperature X-ray diffraction. The compound crystallizes in the triclinic space group P-1 with a = 8.122(3) ?, b = 9.726(3) ?, c = 17.648(6) ?, α = 78.181(4)°, β = 82.797(5)°, γ = 67.439(4)°, Z = 2, V = 1258.4(7) ?³. In the compound, monoprotonated 4,4′-bipyridin-1-ium cations are self-assembled into supramolecular chains along the a-axis through N–H···N hydrogen bonds in a head-to-tail fashion. The chains are stacked via π–π stacking interactions to create two-dimensional sheets. The interlayer space is occupied by the hydrogen-bonded water chains that are linked to the organic sheets via C–H···O interactions and the perchlorate anions that are linked to the water chains and the organic sheets via O–H···O and C–H···O hydrogen bonds, respectively, thus generating a three-dimensional supramolecular architecture. Index Abstract Supramolecular Network via Hydrogen Bonding and π–π Stacking in 4,4′-Bipyridin-1-ium perchlorate dihydrate Jian-Yong Zhang, Ai-Ling Cheng and En-Qing Gao* Monoprotonated 4,4′-bipyridin-1-ium cations are self-assembled into supramolecular chains along the a-axis through N–H···N hydrogen bonds, and these chains are stacked via π–π stacking and hydrogen bond interactions involving water molecules and perchlorate anions.      

Synthesis and Crystal Structure of a New Schiff Base 4-[(2-hydroxy-benzylidene)-amino]-<Emphasis Type="Italic">N</Emphasis>-(5-methyl-isoxazol-3-yl)-benzenesulfonamide

Abstract  The structure of the title compound (C₁₇H₁₅N₃O₄S)₂ the schiff base, bis(N-(5-methyl-3-isoxazolyl)-4-[(2-hydroxy benzylidene)-amino]) benzene sulfonamide was elucidated by H¹, C¹³ NMR, UV–VIS and IR spectroscopic techniques. The X-ray structure was determined in order to establish the conformation of the molecule. The compound crystallizes in the triclinic space group P-1, with a = 11.419(1), b = 11.426(0), c = 13.316(1) ?, α = 71.94(2), β = 89.79(1), γ = 89.14(2)° and Z = 4. Two benzene rings and azomethine group are practically coplanar, as a result of intramolecular hydrogen bonds involving the hydroxy O atom and azomethine N atom. The component species further interact via N–H···N and C–H···O hydrogen bonds and π–π stacking interactions. Index Abstract  The title compound (C₁₇H₁₅N₃O₄S)₂, Schiff base, bis(N-(5-methyl-3-isoxazolyl)-4-[(2-hydroxy benzylidene)-amino]) benzene sulfonamide was synthesized by the condensation of 4-amino-N-(5-methyl-3-isoxazolyl) benzene sulfonamide (SMZ) and 2-hydroxy benzaldehyde (SA). Its structure was confirmed by single crystal X-ray diffraction analysis. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Crystal Engineering: A Salt of Mellitate Ion,MA<Superscript>−2</Superscript>, with Hydronium,H<Subscript>3</Subscript>O<Superscript>+</Superscript>, Containing π–π Stacks of Neutral Phenazine,PZ, in the Crystal

Abstract  The structure of the benznenehexacarboxylic acid (mellitic acid, MA)––phenanthroline (PL) complex (MA⁻²   2PL⁺¹) consisting of infinite stacks of phenanthroline separated for optimum π–π interactions and sandwiched between MA ribbons suggested a design of models with more significant π–π interactions to produce conducting materials. Phenazine (9,10-diazaanthracene) was considered as a promising choice. The X-ray structure of the complex (MA₁–PZ₄) from MA⁻² and neutral PZ was a major surprise since the complex was not only radically different from MA–PL but also the MA exhibited the rare direct interaction with the base PZ. In a novel arrangement, a continuous chain formed by the linking of the peri carboxylic groups of MA⁻² mediated with hydronium ions, H₃O⁺, supports a 4-fold arrangement of four phenazine molecules where four carboxylic groups are engaged in hydrogen bond formation with one of the nitrogens of each PZ. The running chain of MA⁻² supports the formation of stacks of phenazine molecules which are separated by ~3.39–3.60 ?, well suited for π–π overlap. The proximal placement of such threaded modules enables their transformation to layered stacks thus possibly enhancing their π–π interactions. Crystal structure parameters are: sp. gr. C2/c, a = 13.2819(23) ?, b = 11.3669(20) ?, c = 33.3757(57) ?, β = 96.515(3), R ₁ = 0.0521 for 4,198 data (I > 2σ(I)) and wR ₂ = 0.0828 for all 6,194 data. Graphical Abstract  Dark brown thick crystals from MA and phenazine form the sandwiched module (PZ₂–MA⁻²–PZ₂) that assembles vertically to produce infinite π–π stacks of PZ. Isabella L. Karle (Senior Scientist) is responsible for the structure analysis and discussion. Subramania Ranganathan (Professor) is responsible for design of molecule and synthesis.     

Synthesis and Crystal Structure of Nitrogen-rich Compound: 2,5,2′-triazido-1,1′-azo-1,3,4-triazole

Abstract  The title compound 2,5,2′-triazido-1,1′-azo-1,3,4-triazole(2) has been synthesized by the reaction of 2,5,2′-trichloro-1,1′-azo-1,3,4-triazole(1) with sodium azide. Its crystal structure was determined by single-crystal X-ray diffraction. It crystallizes in triclinic, space group P−1 with a = 6.6604(13) ?, b = 6.7035(13) ?, c = 12.916 (3) ?, α = 98.13(3)°, β = 95.56(3)°, γ = 106.48° V = 541.68(18) ?³, Z = 2, C₄HN₁₇, Mr = 287.22, D _c  = 1.761 g cm⁻³, F(000) = 288 and μ(MoKa) = 0.140 mm⁻¹, the final R = 0.0553 and wR = 0.1541. X-ray analysis indicates a stronger delocalization of the azo π bond along the hypothetical N₄ moiety within the title compound than those in(E)-1,2-bis(2,6-diazido-9- azabicyclo[3.3.1]nonan-9-yl)diazene. Index abstract  The title compound 2,5,2′-triazido-1,1′-azo-1,3,4-triazole has been synthesized by the reaction of 2,5,2′-trichloro-1,1′-azo-1,3,4-triazole with sodium azide. Its crystal structure was determined by single-crystal X-ray diffraction. X-ray analysis indicates a stronger delocalization of the azo π bond along the hypothetical N4 moiety within the title compound than those in(E)-1,2-bis(2,6-diazido-9-azabicyclo[3.3.1] nonan-9-yl)diazene.      

3-Methyl-3a,4-Dihydro-3H-Thiochromeno[4,3-c]isoxazol

Abstract  The crystal structure of the title compound, C₁₁H₁₁NOS, was determined by an X-ray diffraction analysis. The compound crystallizes in the monoclinic space group P2₁/c with cell parameters a = 10.533(2) ?, b = 12.7826(19) ?, c = 7.6491(17) ?, β = 107.997(17)^°, V = 979.5(3) ?³ and Z = 4. The S containing heterocycle adopts a sofa conformation, whereas the 5-membered ring adopts an envelope conformation. The crystal packing is characterized by weak C–H···N contacts and π-stacking interactions. Graphical Abstract  The title compound, 3-methyl-3a,4-dihydro-3H-thiochromeno[4,3-c]isoxazol was synthesized by an 1,3 dipolar cycloaddition reaction and its crystal structure determined. Single crystal X-ray diffraction analysis reveals that the aromatic 6-membered ring is planar, whereas the ring containing the S atom adopts a sofa conformation and the 5-membered ring an envelope conformation. The methyl group is in an equatorial position.      

Synthesis and Crystal Structure of New <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-Bis[1-(4-methoxyphenyl)-5-methyl-1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazole-4-carbonyl]hydrazide

Abstract  The N,N′-bis[1-(4-methoxyphenyl)-5-methyl-1H-1,2,3-triazole-4-carbonyl]hydrazide 6 was synthesized from aryl triazole acids and its structure is established by MS, IR, and ¹H NMR spectral data. Compound 6, C₂₂H₂₂N₈O₄, Mr = 462.48, crystallizes in the monoclinic space group P2(1)/c with unit cell parameters a = 15.3451(8), b = 8.6486(4), c = 16.8502(9) ?, α = 90.00, β = 95.731(2), γ = 90.00o, V = 2225.1(2) ?³, Z = 4, and Dx = 1.381 mg m⁻³. The final R was 0.0450. The four aromatic rings are close to linear because of N···H–N hydrogen bonds. Index Abstract  Synthesis and crystal structures of N,N′-bis[1-(4-methoxyphenyl)-5-methyl-1H-1,2,3-triazole-4-carbonyl]hydrazide Heng-Shan Dong, Yan-Fei, Wang, Hong-Ru Dong, Bin, Wang, Bin Quan N,N′-Bis[1-(4-methoxyphenyl)-5-methyl-1H-1,2,3-triazole-4-carbonyl]hydrazide was synthesized.      

Synthesis and Crystal Structure of a Novel Double-Chain Coordination Polymer [Zn<Subscript>2</Subscript>(bipy)<Subscript>2</Subscript>(btec)(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>]<Subscript>n</Subscript> (bipy = 2,2′-bipyridine; btec = 1,2,4,5-benzenetetracarboxylate)

Abstract  A novel aromatic polycarboxylate polymer, [Zn₂(bipy)₂(btec)(H₂O)₂]_n (1), has been synthesized and structurally characterized by the single crystal X-ray diffraction. Compound 1 belongs to the triclinic crystal system, space group P-1; a = 7.7449(6) ?, b = 8.9286(8) ?, c = 10.7422(8) ?, α = 80.95(1)°, β = 70.21(1)°, γ = 78.14(1)°, V = 680.93(10) ?³, Z = 2. The coordination geometry of Zn(II) atom is distorted trigonal bipyramidal with two nitrogen atoms of one 2,2′-bipy group, two oxygen atoms from two different btec ligands, and one water. The 16-membered rings are alternately arranged forming an infinite 1-D double-chain structure. A 3-D network was constructed by interlayer C···H–O, O···H–O hydrogen bonds and π–π stacking interactions. Compound 1 exhibits fluorescence at room temperature in the solid state. Graphical Abstract  A 1-D double-chain aromatic polycarboxylate polymer, [Zn₂(bipy)₂(btec)(H₂O)₂]_n (1), has been synthesized and structurally characterized by the single crystal X-ray diffraction. A 3-D network was constructed by intermolecular C···H–O, O···H–O hydrogen bonds and π–π stacking interactions. Compound 1 exhibits fluorescence at room temperature in the solid state.      

Supramolecular Aggregation in the 1:1 Co-crystal Formed Between Merocyanine Dye and 3-Nitrophenol,Characterized as a Hydrate

Abstract  The title organic salt comprises a (E)-4-[2-(4-hydroxyphenyl)vinyl]-1-methylpyridinium cation, a 3-nitro-phenoxide anion and a solvent water molecule of crystallisation. The anions and water molecules aggregate to form supramolecular chains facilitated by charge-assisted O–H···O hydrogen bonds and these form layers which are interspersed by layers of cations. Interactions between layers include O–H···O hydrogen bonding, as well as C–H···O and C–H···π contacts; π···π and C–H···O contacts are found within layers of cations. The compound crystallizes in the monoclinic space group P2₁/n with a = 15.018(7) ?, b = 7.328(2) ?, c = 17.571(7) ?, β = 112.342(15)°, and Z = 4. Index Abstract  A layer structure comprising alternating anions/water molecules and cations associated via charge-assisted O–H···O hydrogen bonding as well as C–H···O, C–H···π and π···π contacts is found in (II) .     

Crystal Structure of 2′,3′-Di-<Emphasis Type="Italic">O</Emphasis>-Acetyl-5′-Deoxy-5-Fluorocytidine with N–H···(O,F) Proton Donor Bifurcated and (C,N)–H···O Bifurcated Acceptor Dual Three-Center Hydrogen Bond Configurations

Abstract  The title compound, C₁₃H₁₆O₆N₃F, features a central furan ring containing four carbon atom chiral centers with a 4-amino-5-fluoro-2-oxopyrimidine group, two acetyl groups and a methyl group bonded at the 2,3,4,5 positions, each in an absolute R configuration (2R,3R,4R,5R). It crystallizes in the monoclinic space group C2 with unit cell parameters a = 14.5341(3), b = 7.26230(10), c = 16.2197(3) ?, β = 116.607(2)°, Z = 4. An extensive array of intra and intermolecular hydrogen bond interactions dominate crystal packing in the unit cell highlighted by a relatively rare three-center proton-bifurcated donor N–H···(O,F) hydrogen bond interaction in cooperation with a second, (C,N)–H···O bifurcated acceptor three-center hydrogen bond in a supportive fashion. Additional weak Cg π-ring intermolecular interactions between a fluorine atom and the 4-amino-5-fluoro-2-oxopyrimidine ring in concert with multiple donor and acceptor hydrogen bonds significantly influence the bond distances, bond angles and torsion angles of the deoxy-5-fluorocytidine group. Comparison to a MOPAC computational calculation provides support to these observations. Index Abstract  Crystal structure of (2R,3R,4R,5R)-2-(4-amino-5-fluoro-2-oxopyrimidin-1(2H)-yl)-5-methyl-tetrahydrofuran-3,4-diyl diacetate with dual N–H···(O,F) proton donor bifurcated and (C,N)–H···O bifurcated acceptor three-center hydrogen bond configurations is reported and its geometric and packing parameters described and compared to a MOPAC computational calculation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis,Crystal Structure and Fluorescent Study of Bis(2-(2-hydroxyphenyl)benzimidazolate)zinc with Ethanol Solvate

Abstract  The zinc(II) complex with 2-(2-hydroxyphenyl)benzimidazole, namely [Zn(2-(2-hydroxyphenyl)benzimidazolate)₂]·C₂H₅OH (1 · C₂H₅OH) has been synthesized and characterized by X-ray crystallography and photoluminescent analysis. The complex crystallizes in monoclinic space group P2₁/c with cell parameters a = 10.156(1) ?, b = 25.771(3) ?, c = 9.674(1) ?, α = 90°, β = 103.641(2)°, γ = 90°, Z = 4, V = 2460.4(4) ?³. The central Zn(II) is four-coordinate and has a tetrahedral geometry. The steady-state and time-resolved photoluminescent spectra for the title compound have also been studied. The emission property can be ascribed to ligand-centered charge-transfer transition (LCCT) with π → π* property. Index Abstract   A new co-crystal of Zn(II) complex of 2-(2-hydroxylphenyl)benzimidazole with ethanol solvate has been prepared, characterized by X-ray crystallography and fluorescent studies.      

The Synthesis and Crystal Structure of New Bis(3-chlorophenyl)-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-methanol

Abstract  The title compound bis(3-chlorophenyl)-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-methanol 8 has been synthesized and established by H NMR, IR and MS spectra and X-ray diffraction crystallography. Compound 8, C₂₃H₂₉Cl₂N₃O, Mr = 424.31, crystallizes in the monoclinic space group P2₁/c with unit cell parameters a = 14.5402(6) ?, b = 12.5888(5) ?, c = 11.6510(5) ?, α = 90o, β = 100.183o(2), γ = 90o, V = 2099.05(15) ?³, D_x = 1.343 mg m⁻³ and Z = 4. The final R was 0.0514. The molecular conformation and packing is stabilized by interactions of intermolecular O1–H1···N3′. Index Abstract  The structure of bis(3-chlorophenyl)-[5-methyl-1-(4-methylphenyl)-1,2,3-triazol-4-yl]-methanol by the reaction of compound 4 and Grignard regent is studied.      

Structures of two N-{2-([(5-amino-1,3,4-thiadiazol-2-yl)difluoromethyl]-4-halophenyl}acetamides

Abstract  

The compounds, N-{2-[(5-amino-1,3,4-thiadiazol-2-yl)difluoromethyl]-4-chlorophenyl}acetamide (1: X = Cl) and N-{2([(5-amino-1,3,4-thiadiazol-2-yl)difluoromethyl]-4-bromo-phenyl}acetamide (1: X = Br), are isostructural. The molecules are near ‘‘V’’ shaped with the angles between the two aromatic planes ca. 84° in each case. The various intermolecular interactions, namely N–H···O, N–H···N, N–H···F, and C–H···N hydrogen bonds and C–H···π, C–Cl···π and C–O···π interactions, generate 3-D arrays. Compound (1: X = Cl) crystallizes in the monoclinic space group P21/c with a = 16.9032(7) ?, 10.2193(4) ?, c = 7.5227(4) ?, β = 100.179(3)° and Z = 4. Compound (1: X = Br) crystallizes in the monoclinic space group P21/c with a = 17.2119(4) ?, 10.2167(2) ?, c = 7.5677(2) ?, β = 100.326(2)° and Z = 4.     

Hydrogen Bonding in the Crystal Structures of New Imidazolium Triflimide Protic Ionic Liquids

Abstract  The synthesis and crystal structures of 1,3-diamino-2-methylimidazolium bis(trifluoromethylsulfonyl)imide (1), 1,3-dihydroxy-2-methylimidazolium bis(trifluoromethylsulfonyl)imide (2) and 1-(2-(diethylammonio)ethyl)-3-methylimidazolium bis(bis(trifluoromethylsulfonyl)imide) (4) are reported. The salts 1, 2 and 4 have melting points below 100 °C, the intermediate 1-(2-(diethylamino)ethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (3) is liquid at room temperature. Compound 1 is monoclinic, space group P2₁/n with a = 8.4979(4) ?, b = 12.2803(6) ?, c = 13.9400(7) ?, β = 93.086(4)°, and Z = 4. Compound 2 is monoclinic, space group P2₁/c with a = 7.6165(2) ?, b = 20.5323(8) ?, c = 9.7654(3) ?, β = 111.046(2)°, and Z = 4. Compound 4 is triclinic, space group with a = 8.5313(4) ?, b = 9.2157(4) ?, c = 20.5812(8) ?, α = 84.668(2)°, β = 83.738(2)°, γ = 63.096(2)°, and Z = 2. The ions in 1 build a network of N–H···O hydrogen bonds, in 2 they are linked to chains by O–H···N and bifurcated O–H···O hydrogen bonds, whereas in 4 they form pairs by N–H···O contacts. The triflimide anions adopt transoid conformations. Index Abstract  Short interionic contacts, conformational flexibility, and disorder phenomena were identified in the crystal structures of three new, low-melting, protic imidazolium triflimides.      

Crystal and Molecular Structure of <Emphasis Type="Italic">trans</Emphasis>-1,2-bis(2-benzothiazolyl)ethene

Abstract The crystal and molecular structure of trans-1,2-bis(2-benzothiazolyl)ethene is reported. Crystal data for 1: monoclinic, space group C 2/c, a = 24.926(3) ?, b = 4.843(1) ?, c = 11.164(1) ?, β = 105.274(5) °, V = 1300.0(3) ?³, and D _c = 1.50 g/cm³ for Z = 4 and R = 0.028. The molecule crystallizes in the form of a colorless plate and forms one-dimensional slipped π-stacks. Graphical Abstract The title compound crystallizes to form 1D slipped π-stacks in the solid state. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Spectroscopic Studies and Crystal Structure of (<Emphasis Type="Italic">Z</Emphasis>)-6-[(2-hydroxyphenylamino)methylene]-2-methoxycyclohexa-2,4-dienone

Abstract  The Schiff base (Z)-6-[(2-hydroxyphenylamino)methylene]-2-methoxycyclohexa-2,4-dienone has been synthesized from the reaction of 2-aminophenol with 2-hydroxy-3-methoxybenzaldehyde. The title compound has been characterized by elemental analysis, FT-IR, ¹H-NMR, ¹³C-NMR and UV–Visible techniques. The structure of the title compound also was determined crystallographically. The crystal structure has been solved by direct methods and refined by full-matrix least squares. The title compound crystallize in the monoclinic space group P2₁/c with a = 10.438(1), b = 8.851(1), c = 12.746(1) ?, β = 95.72(1)°, V = 1171.7(2) ?³, D _x  = 1.379 g cm⁻³, respectively (R1 = 0.0522 and wR2 = 0.126 for 1442 reflections [I > 2σ(I)]). Index Abstract   N-salicylideneaniline derivatives have been shown to exist as tautomeric forms due to intramolecular proton shifts between the phenol-oxygen and the imine-nitrogen, via intramolecular hydrogen bonding O–H···N or O···H–N.      

Structures of Bis(1-ethylbenzimidazol-2-yl)alkyl Copper(II) Dichlorides: An Unusual Cocrystallization

Abstract  Two structures containing pseudo-tetrahedral Cu(II)N₂Cl₂ coordination complexes are reported. The first molecular structure (A) of the compound, 1,1′bis(1-ethylbenzimidazol-2-yl)propane copper(II) dichloride (triEtBBIM)Cu(II)Cl₂, 1, is reported. The complex crystallized in the triclinic space group P-1 with a = 8.616(3) ?, b = 9.302(3) ?, c = 14.314(4) ?, α = 85.613(6)°, β = 85.170(6)°, γ = 66.117(6)° and V = 1044.1(5) ?³ with Z = 2. The second structure (B) contains 1 and (3,3′bis(1-ethylbenzimidazol-2-yl)pentane) copper(II) dichloride (tetEtBBIM)Cu(II)Cl₂, 2, both of which, cocrystallize in an equal molar ratio with a nitromethane solvate molecule. The complex crystallized in the monoclinic space group P2₁/c with a = 18.876(4) ?, b = 14.975(3) ?, c = 18.344(4) ?, β = 116.75(3)°, and V = 4630.3(16) ?³ with Z = 4. The cocrystallization of such discrete complexes has been coined a chemical Janus. Graphical Abstract  The title complexes contain pseudo-tetrahedral Cu(II)N₂Cl₂ coordination. One of the structures is the result of an unusual cocrystallization, in which two different discrete Cu(II) molecules cocrystallize in an equimolar ratio with a nitromethane solvate molecule.      

Syntheses and Crystal Structures of Two Apigenin Alkylation Derivatives

Abstract Two apigenin alkylation derivatives, 4′,7-dimethoxyl-5-hydroxyflavone (I) and 4′,7-diethoxyl-5-hydroxyflavone (II), have been synthesized and their crystal structures were determined by ¹H NMR and single crystal X-ray diffraction study. (I) is triclinic, space group P−1 with a = 7.120(5) ?, b = 7.297(5) ?, c = 13.559(10) ?, α = 89.313(12)°, β = 86.298(12)°, γ = 83.999(13)° and Z = 2. (II) is monoclinic, space group P 2₁ /c with a = 16. 309(4) ?, b = 7.303(2) ?, c = 15.185(4) ?, α = 90.00°, β = 115.70(2)°, γ = 90.00° and Z = 4. They have the same flavone skeleton which is composed of a benzopyranone moiety and a phenyl moiety. Molecules of (I) are linked into a two-dimensional network by a combination of C–H···O hydrogen bond and π–π stacking interactions. (II) shows some discrepancies with (I) and the molecules are linked into a column by π–π stacking interaction. Graphical Abstract Two apigenin alkylation derivatives, 4′,7-dimethoxyl-5-hydroxyflavone (I) and 4′,7-diethoxyl-5-hydroxyflavone (II) were synthesized and their crystal structures were determined by single-crystal X-ray diffraction. Hydrogen bonding and π–π stacking interactions assemble (I) into a two-dimensional network, and in the crystal structure of (II), π–π stacking interaction leads to the formation of a column.