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.     

The Synthesis and Structure of Two Novel <Emphasis Type="Italic">N</Emphasis>-(Benzothiazol-2-yl)benzamides

Abstract  Two novel benzothiazoles 2-chloro-N-(benzothiazol-2-yl)benzamide (1) and 2-chloro-N-(6-cyanobenzothiazol-2-yl)benzamide (2) were obtained in multistep synthesis. They were characterised by means of IR, ¹H- and ¹³C-NMR spectroscopy and also by single-crystal X-ray diffraction. The compound 1 crystallises with triclinic space group P , a = 9.5923(8) ?, b = 9.8583(8) ?, c = 13.8962(10) ?, α = 89.162(6)°, β = 77.741(7)°, γ = 80.064(7)°, V = 1264.5(2) ?³, Z = 4 and compound 2 crystallises as methanol solvate with monoclinic space group P 2₁/n, a = 7.5093(9) ?, b = 13.0211(14) ?, c = 16.032(2) ?, β = 92.717(10)°, V = 1565.9(3) ?³, Z = 4. Both crystal structures consist of discrete dimers connected into a three-dimensional network by intermolecular C–H···O and C–H···X (X = Cl or S) hydrogen bonds and by face-to-face π–π stacking interactions. Index Abstract  The synthesis and structure of two novel N-(benzothiazol-2-yl)benzamides. Irena Ćaleta, Dominik Cinčić, GraceKarminski-Zamola and Branko Kaitner. Hydrogen bonds and π–π interactions in N-(benzothiazol-2-yl)benzamides N-(benzothiazol-2-yl)benzamides.      

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.      

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.      

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.     

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.     

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.      

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.     

Synthesis and Crystal Structure of Heptyl 3-(3,4-dihydroxyphenyl)-2-propenoate

Abstract  The title compound, C₁₆H₂₂O₄, synthesized by modified Knoevenagel condensation of protocatechualdehyde with monoheptyl-malonate and recrystallized from benzene, was confirmed by single-crystal X-ray diffraction (CCDC 272827). The compound crystallizes in triclinic space group Pī with cell parameters a = 5.296(3) ?, b = 10.711(13) ?, c = 13.870(4) ?, α = 98.84(7)°, β = 90.97(4)°, γ = 96.77(7)° and Z = 2. The structure is the E isomer and its packing is stabilized by intermolecular O–H···O and C–H···O hydrogen bonds. Index Abstract  The title compound, C₁₆H₂₂O₄, synthesized by modified Knoevenagel condensation, was confirmed by single-crystal X-ray diffraction showing its structure is in E isomer and its packing is stabilized by hydrogen bonds.      

Crystallographic and Conformational Analysis of [(<Emphasis Type="Italic">E</Emphasis>)-2-[(3-Chlorophenylimino)methy])-4-methoxyphenol]

Abstract  The crystal structure of C₁₄H₁₂ClNO₂ was determined by X-ray analysis. It crystallizes in the triclinic space group Pc with a = 12.5346(10) ?, b = 4.5101(3) ?, c = 12.0534(11) ?, α = 90.00o, β = 113.669(6)o, γ = 90.00o, Z = 2, Dx = 1.393 mg/m³, μ (MoK_α) = 0.298 mm⁻¹. The title compound is photochromic and molecule is non-planar. It adopts a phenol–imine tautomeric form with a strong intramolecular O–H···N hydrogen bond and a strong intermolecular C–H···O hydrogen bond. Minimum energy conformations AM1 were calculated as a function of the three torsion angles θ1(C10–C9–N1–C8), θ2(C9–N1–C8–C1) and θ3(N1–C8–C1–C6), varied every 10°. As in the X-ray experiment results, molecule has an angle that makes it non-planar between two aromatic rings in AM1 optimized geometry. Graphical Abstract  Molecular and crystal structure of [(E)-2-[(3-chlorophenylimino)methy])-4-methoxyphenol], C₁₄H₁₂ClNO₂, have been determined by single crystal X-ray diffraction study, and conformational analysis of the title molecule with respect to the selected torsion angle has been achieved by AM1 semi-empirical calculations.      

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.      

Synthesis and Structural Characterization of <Emphasis Type="Italic">N</Emphasis>-(2-Pyridylmethyl)-3-Methoxysalicylaldiminato Copper(II) Chloride

Abstract  The copper(II) complex [Cu(C₅H₄NCH₂−N=CH–C₆H₃OCH₃–O)Cl], (1) containing a new tridentate Schiff base ligand (LH), which is the 1:1 condensation product of 2-(aminomethyl)pyridine and o-vaniline, has been synthesised and characterized by IR and UV–Vis spectra. Structural investigation shows that 1 crystallizes to a monoclinic system, having space group P2(1)/c, a = 6.9634(7), b = 18.1209(19), c = 10.3448(11) ?, α = 90°, β = 103.97(2)°, γ = 90° and Z = 4. The coordination geometry around the copper atom is slightly distorted square planar, formed by the N₂O donor set of the Schiff base and one Cl atom. The Cu–N(1), Cu–N(2), Cu–O(1) and Cu–Cl bond distances are 2.0114(14), 1.9414(14), 1.9147(12) and 2.2520(5) ?, respectively. Index Abstract  The copper(II) complex [Cu(C₅H₄NCH₂−N=CH–C₆H₃OCH₃–O)Cl], (1) containing a tridentate Schiff base ligand (LH), synthesised and characterized by IR and UV–Vis spectra. The central copper ion possesses a distorted square-planar geometry.      

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.      

Intermolecularly Associated Carboxylic Acid Dimers in the Supramolecular Assembly of (R)-1,4-Benzodioxane 2-Carboxylic Acid

Abstract  The title compound, C₉H₈O₄, (I), crystallizes in the monoclinic space group P 21/c with unit cell parameters a = 7.3380(5) ?, b = 9.3790(7) ?, c = 12.3172(9) ?, β = 90.687(7)°, Z = 4. The molecule consists of a benzene ring fused to a 1,4 dioxane ring in a half-chair conformation with a carboxylic acid group bonded at the dioxane 2-position. The carboxylic acid group forms a classic O–H···O hydrogen bonded dimer with an O···O distance of 2.6292(12) ? in a R₂² (8) graph-set motif which links the molecules into pairs around inversion centers in a supramolecular assembly in the unit cell. The dihedral angle between the mean planes of the R₂² (8) graph-set motif’s of two adjacent dimers in the unit cell is 75.7(5)°. The mean plane of an R₂² (8) graph-set motif makes an angle of 88.4(5)° with the mean plane of the benzene ring in the same dimer and 13.1(2)° or 13.4(7)° with the mean plane of a benzene ring from an adjacent dimer. Additional weak Cg π-ring intermolecular interactions significantly influence the bond distances, bond angles and torsion angles of the dioxane ring and attached carboxyl group. Comparison to a MOPAC AM1computational calculation provides support to these observations. Graphical Abstract  The association of carboxylic acid dimers in the supramolecular assembly of (R)-1,4-benzodioxane 2-carboxylic acid is investigated by examination of its crystal structure. Its geometric and packing parameters are described and compared to a MOPAC AM1 computational calculation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

The co-crystal of iron(II) complex hydrate with hydroxybenzoic acid: [Fe(Phen)<Subscript>3</Subscript>]Cl(p-hydroxybenzoate).2(p-hydroxybenzoic acid).7H<Subscript>2</Subscript>O

Crystal of [Fe(Phen)₃]Cl(PHB).2(PHBH).7H₂O (1) is triclinic, space group P-1 with a = 12.0388(11) ?, b = 15.5286(14) ?, c = 15.7794(14) ?, α = 89.759(2)°, β = 75.818(2)°, γ = 71.900(2)° and Z = 2, (phen = phenanthroline, PHBH = p-hydroxybenzoic acid, PHB = p-hydroxybenzoate anion). The phen in adjacent Fe(phen)₃ ²⁺ cations are π–π interacted forming offset face to face (OFF) motifs. Juxtaposition of four phen ligands from two cations encapsulate an R₂ ²(8) dimeric unit of H-bonded PHBH molecules within a centrosymmetric box froming a filled aryl box motif (FAB). Alternation of OFF and FAB motifs form {OFF⋯FAB}∞ strands. The Fe(phen)₃ ²⁺ cation engages its phen ligands in π–π and/or CH–π interactions with two crystalographically different PHBH molecules and one PHB anion. Seven water molecules and a chloride anion per iron(II) trisphenanthroline cation fill empty spaces in the structure forming a hydrophilic cluster. Extensive intermolecular H-bond interactions occur between water molecules, chloride anions, PHBH molecules, and PHB anions. Thermal analysis of (1) was done under N_2(g). The TG, and dTG curves revealed the expected mass losses. All associated processes are endothermic as shown in the DSC curve.     

Crystal and Molecular Structure of the 1:2 Salt Formed Between 1,2-(4-Pyridyl)Ethane and 2-(4-Hydroxyphenylazo)Benzoic Acid

Abstract  Proton transfer occurred during co-crystallization of 1,2-(4-pyridyl)ethane with 2-(4-hydroxyphenylazo)benzoic acid to yield a salt comprising a 1:2 ratio of 1,2-bis(4-pyridinium)ethane dications and 2-(4-hydroxyphenylazo)benzoate anions. Centrosymmetrically related anions associate by charge-assisted O–H···O hydrogen bonds to form 24-membered {···OC₃N₂C₄OH}₂ synthons. These are connected into a supramolecular polymer via charge-assisted N–H···O hydrogen bonds involving the 1,2-bis(4-pyridinium)ethane dications. The compound crystallizes in the triclinic space group P−1 with a = 8.517(4) ?, b = 9.110(5) ?, c = 10.477(5) ?, α = 96.850(13)°, β = 94.446(12)°, γ = 104.946(10)° and Z = 1 {two anions and a dication}. Index Abstract  Supramolecular chains mediated by charge-assisted O–H···O and N–H···O hydrogen bonding are found in the salt containing a 1:2 ratio of 1,2-bis(4-pyridinium)ethane dications and 2-(4-hydroxyphenylazo)benzoate anions.      

Synthesis and Crystal Structure of 2-(2,3,4-Trimethoxy-6-Methylbenzylideneamino)phenol

Abstract  The title compound 2-(2,3,4-trimethoxy-6-methylbenzylideneamino)phenol (C₁₇H₁₉NO₄, M _r = 301.33) was synthesised and characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c, with a = 10.4458(14), b = 8.3870(10), c = 17.780(2) ?, β = 91.102(2)^°, V = 1557.4(3) ?³, Z = 4, D _c = 1.285 g/cm³, λ = 0.71073 ?, μ(Mo Kα) = 0.092 mm⁻¹, F(000) = 640. The final refinement gave R = 0.0452, wR(F ²) = 0.1065 for 2,743 observed reflections with I > 2σ(I). X-ray diffraction analysis reveals that the molecule adopts an E configuration at the C=N functional bond. The dihedral angle between the two phenyl rings is 38.3(3)°. The crystal structure is stabilized by C–H···O, O–H···O and O–H···N hydrogen bonds and π–π stacking interactions. Graphical Abstract  The title compound 2-(2,3,4-trimethoxy-6-methylbenzylideneamino)phenol (C₁₇H₁₉NO₄, M _r = 301.33) was synthesised and characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c, with a = 10.4458(14), b = 8.387(1), c = 17.780(2) ?, β = 91.102(2)°, V = 1557.4(3) ?³, Z = 4, D _c = 1.285 g/cm³, λ = 0.71073 ?, μ(Mo Kα) = 0.092 mm⁻¹, F(000) = 640. The final refinement gave R = 0.0452, wR(F ²) = 0.1065 for 2,743 observed reflections with I > 2σ(I). X-ray diffraction analysis reveals that the molecule adopts an E configuration at the C=N functional bond. The dihedral angle between the two phenyl rings is 38.3(3)°. The crystal structure is stabilized by C–H···O and O–H···O hydrogen bonds and π–π stacking interactions.      

Synthesis and crystal structure of Mn(II) and Zn(II) complexes with 1,3,5-tris(carboxymethoxyl)benzene ligand

Two complexes (H₂bipy)[M₂(TB)₂(H₂O)₈]·5H₂O (M = Mn 1, Zn 2) (bipy = 4,4′-bipyridine, H₃TB = 1,3,5-tris(carboxymethoxyl)benzene) were synthesized by the reaction of the corresponding metal salt with ligand H₃TB and 4,4′-bipy in an aqueous methanol solution at room temperature, respectively. Their structures were determined by single crystal X-ray diffraction analysis. Both complexes 1 and 2 crystallize in the triclinic space group with the crystal parameters of 1: a = 9.725(12) ?, b = 10.651(13) ?, c = 10.882(13) ?, α = 91.72(2)°, β = 96.41(2)°, γ = 97.72(2)°, V = 1109(2) ?³, Z = 1 and 2: a = 9.610(10) ?, b = 10.55(2) ?, c = 10.83(2) ?, α = 91.60(4)°, β = 95.32(2)°, γ = 97.73(4)°, V = 1082(3) ?³, Z = 1. Complexes 1 and 2 have the same dinuclear structure, in which each metal atom is six coordinated with distorted octahedral geometry by two oxygen atoms from two different TB³⁻ ligands and four ones from four coordinated water molecules. The dinuclear units are further linked by hydrogen bonding and π–π interactions to form the three-dimensional framework structure.     

Conformational diversity: Six conformers side-by-side in the crystal cell of 2,2′,7,7′-tetramethoxy-9,9′-spiro-9-silabifluorene

X-ray crystal structure analysis of a sublimation-grown spiro silabifluorene, that is highly fluorescent in the violet-blue, established that there are six cocrystallized ordered conformers in the asymmetric unit. Crystals were grown by a vapor transport method under argon gas flow at temperatures between 255–280°C. As expected, there are no cocrystallized solvent molecules. There is no π-stacking of the aryl groups. There is no possibility for normal hydrogen bond formation; however, several CH⋯π bonds occur. The packing is efficient with a density of 1.24 g/cc. Each conformer deviates from tetrahedral geometry around the Si atom. Cell data are: C₂₈H₂₄O₄Si×12, sp. gr. P, a=16.2750(5) ?, b=20.6613(5) ?, c=23.8289(5) ?, α=102.025(2)°, β=94.252(2)°, and γ=109.916(2)°, V=7275(1) ?³.