First example of cocrystals of polymorphic maleic hydrazide

The first cocrystals of polymorphic maleic hydrazide with 3-methyluracil have been studied by X-ray diffraction methods. They crystallize in the orthorhombic system, space group Pmcn, a = 6.440 (1) Å, b = 6.974 (1) Å, c = 22.829 (11) Å, V = 1025.3 (5) ų, Z = 4. The asymmetric unit contains one molecule of each compound. Planar ribbons of the (1:1) molecular complex are obtained through the formation of O–H···O and O–H···N intermolecular hydrogen bonds, just forming a well-known R² ₂(8) supramolecular synthon. Supramolecular assemblies are then formed by weak C–H···O and C–H···N hydrogen bonds through adjacent antiparallel ribbons.     

Di-hydroxy malonic acid as a building block of hydrogen-bonded 3-dimensional architectures

An examination of the crystal structures of di-hydroxy malonic acid 1 (P2₁/na = 5.384(2), b = 6.268(2), c = 14.354(8) Å, = 103.57(3)°) and N-ethylbenzylammonium di-hydroxy hydrogenmalonate 2 (P2₁2₁2₁ a = 13.373(2), b = 15.342(4), c = 18.741(4) Å,) has highlighted the influence of directional O–H···O interactions in the assembly of hydroxy-substituted dicarboxylic acids. The complementarity of carboxylic and hydroxy groups in 1 creates a very dense 3-D structure (D _c = 1.919 g cm^–3) through four O–H···O hydrogen bonds. In 2, the anions form infinite, spiraling chains created by head-to-tail O–H···O hydrogen bonds. Neighbouring chains are crosslinked into a complex 3-D anionic network with channels parallel to a and b. The cations are positioned within these channels and held in place via two N–H···O interactions.     

Intramolecular hydrogen bonding and tautomerism in N-(3-pyridil)-2-oxo-1-naphthylidenemethylamine

N-(3-pyridil)-2-oxo-1-naphthylidenemethylamine (C₁₆H₁₂N₂O) was studied by elemental analysis, IR, ¹H NMR, and UV–visible techniques and X-ray diffraction methods. The UV–visible spectrum of the compound was investigated in solutions effect polarity. The polarity of the some solvents was modifierly the additional (CF₃COOH) and [(C₂H₅)₃N]. The compound is in tautomeric equilibrium (phenol-imine O–H···N and keto-amine O···H–N forms) in polar and nonpolar solvents. The keto-amine form is observed in basic solutions of DMSO, ethanol, chloroform, benzene, cyclohexane, and in acidic solutions of chloroform and benzene, but not in acidic solutions of DMSO and ethanol. The compound crystallizes in the monoclinic, space group P2₁/a with a = 7.010(5) Å, b = 13.669(4) Å, c = 12.764(4) Å, = 101.23(4)°, V = 1199.6(10) ų, Z = 4, D _c = 1.375 g/cm³, (Mo K) = 0.088 mm^–1, R = 0.045 for 1658 reflections [I > 2(I)]. The title compound is not planar two Schiff base moieties A [C1–C11, O1] and B [N1, C12, C13, N2, C14, C15, C16] are inclined at an angle of 27.4(1)° reflecting mainly the twist about C12–N1 [C11–C12–N1–C13, 29.7(2)°]. There is a strong intramolecular hydrogen bond (O–H···N) of 2.529(2) Å.     

One-dimensional chain structure based on bifurcated hydrogen bonding

The structure of complex [PyH][Ni(mnt)₂], as determined by X-ray single crystal analysis, consists of pyridinium cations and [Ni(mnt)₂]^– anions. Crystallographic data for the complex: monoclinic P2₁/c, a = 16.5430(18) Å, b = 6.3847(9) Å, c = 17.430(2) Å, = 118.040(7)°, V = 1625.4(3) ų, Z = 4. The [Ni(mnt)₂]^– anion is not a planar and the CN groups bend away from the S₄ plane. The interactions between anions and cations via the formation of bifurcated N–H···NC hydrogen bonds give rise to an 1D zigzag chain of alternating cations and anions.     

Crystal structure of N-benzylmethylammonium dihydrogen-monophosphate monohydrate, [C6H5CH2NH2CH3]H2PO4·H2O

The salt N-benzylmethylammonium dihydrogenmonophosphate monohydrate is monoclinic with the following unit cell dimensions: a = 6.356(1)Å, b = 8.385(7)Å, c = 11.472(5)Å, = 104.32(1)°, space group P2₁ with Z = 2. The structure consists of infinite parallel two-dimensional [110] planes built of mutually connected ions and water molecules by strong O–H···O and N–H···O hydrogen bonding. There are no contacts other than normal van der Waals interactions between the layers.     

Dalspinin, an isoflavone from Dalbergia spinosa roots

The X-ray crystal structure of the plant isoflavone dalspinin from Dalbergia spinosa is determined. The compound, C₁₇H₁₂O₇, is monoclinic in P2₁/n with a = 3.970(1), b = 23.607(5), c = 14.633(3) Å, = 94.46(3)°, V = 1367.2(5) ų, D _calc = 1.595 g cm^–1 and Z = 4. The molecular structure is characterized by a short intramolecular O–H···O=C hydrogen bond, and a large tilt angle of the two rigid ring systems with respect to each other. The intermolecular interactions in the crystal are discussed.     

Crystal structure of a one-dimensional ladder-shape CoII complex through hydrogen bonds with an amino-acid-like ligand 1,5-diazacyclooctane-N,N′-diacetate acid

The crystal structure of a one-dimensional ladder-shape complex [CoL(H₂O)]·2H₂O, (L being 1,5-diazacyclooctane-N,N-diacetate acid), has been determined by X-ray diffraction analysis: monoclinic, space group P2₁/c with a = 14.406(4) Å, b = 7.380(2) Å, c = 14.594(5) Å, = 112.685(2)°, M _r = 341.23, V = 1431.5(8) ų, Z = 4. The Co^II center is penta-coordinated by two O atoms of the carboxylic pendant arms, two nitrogen donors of the 1,5-diazacyclooctane (DACO) moiety, and a water molecule. The coordination geometry of Co^II could be described as a distorted square pyramid and the DACO backbone adopts a normal boat/chair conformation. The complex forms a one-dimensional ladder-shape structure through inter- and intra-molecular O—H···O hydrogen bonds.     

Synthesis and crystal structure of 4,4′-bis(4-pyridylethyl)biphenyl, noncovalently hydrogen bonded two-dimensional networks

A new pyridine containing compound, 4,4-bis(4-pyridylethyl)biphenyl 1, was synthesized and its structure was determined by X-ray crystallography. Two kinds of two-dimensional networks linked by hydrogen bonds were obtained with different crystal solvents: 1·2H₂O, monoclinic, space group P2₁/n with a = 8.3280(10), b = 5.5990(10), c = 24.054(4) Å, = 98.79(2)°, V = 1108.4(3) ų, Z = 2, Dc = 1.200 g cm^–3, R1 = 0.0558; 1·CH₃OH·2H₂O, triclinic, space group P-1 with a = 8.3310(10), b = 12.861(2), c = 13.111(2) Å, = 64.110(10), = 75.000(10), = 83.750(10)°, V = 1220.7(3) ų, Z = 2, Dc = 1.177 g cm^–3, R1 = 0.0529. It is interesting that in the hydrate the host molecule of 1 contains an essentially flat biphenyl section, while in the methanol complex the host molecule of 1 contains a substantial twist in the center of the biphenyl section. The compounds were also characterized by NMR and FTIR spectroscopies. The ¹H and ¹³C NMR assignments for 1 were carried out by 2D NMR spectral measurements in acetonitrile-d ₃.     

Very strong hydrogen bonds in hydrated 1:1 adducts of an olefinic double betaine with perchloric and nitric acids: L·HClO4·H2O and L·HNO3·H2O [L=cis-(p-Me2N+C5H4N)2C2(COO−)2]

The hydrated 1:1 adducts of an olefinic double betaine with perchloric and nitric acids, L·HClO₄·H₂O I and L·HNO₃·N₂O2 [L=cis-(p-Me₂N⁺C₅H₄N)₂C₂(COO^–)₂], have been shown to be nearly isostructural by X-ray crystallography and infrared spectroscopy. The common cationic unit HL⁺ of both compounds exhibits significant semi-quinonoid character and possesses symmetrym, ist two coplanar carboxylate groups being linked by a very strong, nearly linear intramolecular O–H–O hydrogen bond [O...O 2.397(9)Å and O–H–O 167.1° for1; 2.388(7)Å and 167.4° for2]. The HL⁺ units are further connected by intermolecular O–H...O hydrogen bonds between the exocyclic carboxyl oxygen atoms and the water molecules to generate polymeric zigzag chains running parallel to thec axis, and the disordered ClO₄ or NO ₃ ^– anions occupy channels running parallel to thea axis in the resulting host lattice.     

A novel vanadyl selenite templated by organic salt: [(VO)(H2O)2(SeO3)]2[(H2pipe)SO4]

The title compound [(VO)(H₂O)₂(SeO₃)]₂[(H₂pipe)SO₄] was synthesized under hydrothermal condition with VOSO₄, piperazidine (pipe), and SeO₂, and its crystal structure was established using single-crystal X-ray diffraction method. The title compound was characterized with IRFluorescence. The crystal data: P-1 (No. 2), a = 8.633(2) Å, b= 9.223(2) Å, c= 12.508(3) Å, =109.28(3)°, =90.42(3)°, = 107.79(3)°, Mr = 644.08, V=888.5(3) ų, Z=2, Dc = 2.407 g cm^–3, =5.350 mm^–1, F(000)=632. The structure of the title compound consists of an infinite neutral ladder chain, which is built up from VO₆ octahedral and SeO₃ pyramidal units sharing vertices, and organic salt. The biprotonized pipe (piperazidine) and SO₄ ^2– interact with one another and the inorganic chain through strong hydrogen bonds N–H···O or O–H···O to give a 3D structure. Hydrogen bonds play a role of stabilization structure.     

Organic/inorganic hybrid compound: α-Dodecamolybdophosphoric acid–3-(4,5-diazafluoren-one)-3–water

In the title compound (C₁₁H₆N₂O)₃·H₃PMo₁₂O₄₀·3H₂O(1), the -dodecamolybdophosphoric acid residue has the Keggin structure, with M–O distance ranging between 1.673(5) and 2.464(4) Å. The water molecules are involved in O–H···N and O–H···O intermolecular hydrogen bonds with the diazafluoren moiety and -dodecamolybdophosphoric acid respectively while the diazafluoren moiety and -dodecamolybdophosphoric acid are connected through C–H···O interactions. The O–H···O intermolecular hydrogen bonds form infinite chains of Mo₁₂O₄₀ units in which N···O contacts interconnect the chains to form layers.     

Conformation and structure of 1,3-bis(2-hydroxy-5-bromosalicylideneamine)propan-2-ol

The Schiff base, 1,3-bis(2-hydroxy-5-bromosalicylideneamine)propan-2-ol, has been studied by AM1 semiempirical quantum mechanical method and X-ray analysis. It crystallizes in the orthorhombic space group Pca2₁ with a = 8.458(3), b = 6.139(2), c = 32.957(4) Å, D_calc = 1.770 g cm^-3, V = 1711(1) ų, Z = 4 and (MoK) = 0.476. The structure was solved by direct methods and refined to R = 0.041 for 1715 independent reflections [I > 2 (I)]. The title compound is not planar. Intramolecular hydrogen bonds are found between the hydroxyl and the amine nitrogen with O—H···N distances of 2.601(6) and 2.629(4) Å. There is also an intermolecular O—H···N hydrogen bond [3.176(6) Å] linking the neighbouring molecules. Minimum energy conformations from AM1 were calculated as a function of eight torsion angles varied every 5°. The optimized geometry of the crystal structure corresponding to the nonplanar conformation is the most stable conformation in all calculations. The results strongly indicate that the minimum energy conformation is primarily determined by nonbonded hydrogen—hydrogen repulsions.     

Crystal structure of the cytotoxic marine alkaloid 2-bromoleptoclinidinone

2-Bromoleptoclinidinone methanol solvate, C₁₈H₈BrN₃O·CH₄O, crystallizes in the orthorhombic space group Pbca with a = 15.7013(2), b = 7.3308(1), and c = 26.9326(1) Å. The molecule is essentially planar, with the largest deviations occurring at bromine (–0.21 Å), carbonyl oxygen O(l) (+0.19 Å) and in ring-A (C(9) –0.15 Å, C(10) –0.15 Å). Methanol occupies the 1,10-phenanthroline-like metal binding site of the title compound.     

Helical chirality of pyrrolo[1,2-a][1,10]phenanthroline derivatives

The objective of the study was to confirm by X-ray analysis the phenomenon of helical chirality inferred from solution ¹H-NMR data for a series of derivatives based on the novel pyrrolo[1,2-a][1,10]phenanthroline system. The syntheses of the title compounds and their ¹H-NMR data are presented. Crystals of the representative compound ethyl, 1-(4-phenylbenzoyl)-pyrrolo[1,2-a][1,10]phenanthroline-3-carboxylate, with molecular formula C₃₁H₂₂N₂O₃, were found to crystallize in the triclinic system, space group P 1 with a = 7.8541(1), b = 11.2605(2), c = 13.4093(3) Å, = 92.244(1), = 90.292(1), = 106.475(1) and Z = 2. The X-ray analysis revealed the predicted helicity of the phenanthroline system as well as its origin, namely the proximity of the pyridine N atom and the carbonyl C atom of the phenylbenzoyl residue, with non-bonded distance N s C of only 2.465(2) Å. A secondary, but significant distortion, involving displacement of the carbonyl C atom by more than 0.5 Å from the pyrrole ring, was evident. The crystal structure is maintained by C–H s O hydrogen bonds and – interactions.     

Synthesis and structure of (±)-4-O-methanesulfonyl-myo-inositol 1,3,5-orthoformate

Racemic 4-O-methanesulfonyl-myo-inositol 1,3,5-orthoformate was prepared by methanolysis of racemic 2,4-di-O-benzoyl-4-O-methanesulfonyl-myo-inositol 1,3,5-orthoformate, in the presence of triethylamine. The diol crystallizes in space group P2₁2₁2₁ with cell dimensions a = 6.094(1), b = 6.502(2), c = 25.947(3) Å, V = 1028.1(4) Å, Z = 4. The molecular crystals show both intra- and intermolecular O—H···O short contacts. The methine and the methyl hydrogens are involved in several C—H···O interactions.     

Synthesis and crystal structure of two vanadium(V) hydroxylamido complexes with amino acid ligands

Two vanadium(V) hydroxylamido complexes with amino acid ligands including Alanine, [VO(NH₂O)₂(Ala)]·2H₂O, and Threonine, VO(NH₂O)₂(Thr), were synthesized and characterized by elemental analyses, IR spectrum, and single crystal X-ray diffraction. The two complexes are seven-coordinated with four nitrogen atoms and three oxygen atoms in pentagonal bipyramidal geometry. The different hydrogen bonds (N–H···O, O–H···O) observed in the two complexes result in the two-dimensional network structure. [VO(NH₂O)₂(Ala)]·2H₂O belongs to monoclinic: space group P2(1)/c, with a = 21.874(13) Å, b = 8.874(5) Å, c = 15.865(9) Å, = 100.423(8)°, V = 3029(3) ų, Z = 12, D _c = 1.678 g/cm³, (MoK) = 1.002 mm^–1, F (000) = 1584, and final R ₁ = 0.0375, wR ₂ = 0.0886 for observed reflections 1189 (IT > I> 2(I)). VO(NH₂O)₂(Thr) is rhombohedral: space group R-3, with a = 21.460(16) Å, b = 21.460(16) Å, c = 11.184(12) Å, = 120°, V = 4461(7) ų, Z = 18, D _c = 1.669 g/cm³, (MoK) = 1.012 mm^–1, F(000) = 2304, and final R ₁ = 0.0356, wR ₂ = 0.0924 for observed reflections 1306 (I > 2(I)).     

Synthesis and crystal structure of [Y(NO3)3(OH2)3]·(Me2-16-crown-5)·H2O

The complex [Y(NO₃)₃(OH₂)₃]·(Me₂-16-crown-5)·H₂O has been prepared and its crystal and molecular structure determined using single crystal X-ray diffraction. The colorless crystals belong to the monoclinic space group P2₁/n with Z = 4. Lattice parameters are a = 10.420(1), b = 17.257(3), c = 14.646(2) Å, = 96.79(1)°, V = 2615.1(6) ų. The yttrium(III) ion is nine-coordinate, bonded to three bidentate nitrate groups and three water molecules. The average Y–O(nitrate) and Y–O(water) distances are 2.42(3) and 2.33(1) Å, respectively. The average HO–H···O hydrogen bonded separation is 2.767Å.     

Crystal structure of 4-methylpyridinium 2,4-dinitrophenolate

A crystalline salt of 4-methylpyridinium 2,4-dinitrophenolate has been prepared and characterized by X-ray crystallography. The salt crystallizes in the monoclinic space group P2_1/c with a = 9.105(2), b = 7.617(2), c = 18.424(3) Å, = 90.00, = 101.19(1), = 90.00°, V = 1253.5(5) ų, and Z = 4. In the title salt, the phenolate and pyridinium ion are held by bifurcated hydrogen bonds of N–H···O, and are arranged in an almost coplanar manner to each other due to two sets of CHO hydrogen bonds. The geometrical arrangement in the title salt is characterized by the formation of herringbone motif of 4-methylpyridinium 2,4-dinitrophenolate. The herringbone motif is stablized by CHO hydrogen bonds. The face-to-face interval between the phenolate and pyridinium ring is 3.3094 Å, in a range governed by – interaction.     

Anticooperative C—C—H···O···H—O hydrogen bonding in 5β-Hydroxy-5α-ethynyl-10β-methyl-Δ1(9)-octalin-2-one

In the x-ray crystal structure of the alkynol 5-hydroxy-5-ethynyl-10-methyl-¹⁽⁹⁾-octalin-2-one [C₁₃H₁₆O₂, Pbca, a = 10.244(7), b = 12.734(2), c = 17.125(2) Å, Z = 8], the hydroxyl and ethynyl groups are involved in a hydrogen bond arrangement C—C—H···O···H—O, which is supposed to be anticooperative, i.e., weaker than the sum of two isolated hydrogen bonds.     

The crystal structures of p-iodo-N-(p-cyanobenzylidene)aniline and p-cyano-N-(p-iodobenzylidene)aniline

The crystal structures of the isomers NC–C₆H₄–CH=N–C₆H₄–I (CN/I) and I–C₆H₄–CH=N–C₆H₄–CN (I/CN) have been determined. CN/I is triclinic, space group P1¯ with a = 7.504(3), b = 11.936(4), c = 7.304(2) Å, = 93.09(2), = 110.49(2), = 99.04(2)°, V = 601.1(3) ų, Z = 2, and D _x = 1.818(1) g cm^–3. In both compounds there are chains of molecules held together by CN···I interactions, with N···I distances of 3.15 and 3.26 Å, respectively. The chains form similar two-dimensional sheets, which, however, stack differently in the two compounds.