Synthesis and X-ray crystal structure studies of 1-ethyl-3-(2-chlorophenyl)-1,2,3-triazolium perchlorate

The isolation of stable carbenes of the Arduengo (1a) and Wanzlick (2a) type has prompted us to look for stable nitrenium ions of the related structural type 1-ethyl-3-(2-chloropenyl)-1,2,3-triazolium perchlorate (6⁺ClO₄ ^–). The title compound was synthesized and the structure was investigated by X-ray crystallography. It crystallizes in the monoclinic space group P2 ₁/n with cell parameters a = 7.066(4) Å, b = 27.680(6) Å, c = 7.486(2) Å, = 111.22(3)°, and Z = 4. The structure exhibits arrangement of the molecules with intermolecular hydrogen bonds within the layers.     

Structure of a monoclinic polymorph of N-[4-(acetyloxy)-phenyl]acetamide, a prodrug of acetaminophen

The preparation, single crystal x-ray structure and the computed powder XRD pattern of a monoclinic polymorph of N-[4-(acetyloxy)phenyl]acetamide, a prodrug of acetaminophen, are reported. The polymorph crystallizes in the space group P2₁/n with Z = 4 and unit cell dimensions a = 7.219(2), b = 8.015(2), c = 16.575(2) Å, = 92.07(1)°, and V = 958.4(4) ų. Infinite spiral molecular arrays result from intermolecular head-to-tail hydrogen bonding between the amidic H atom of one molecule and the acetoxy carbonyl oxygen atom of a 2₁-related molecule.     

Crystal and molecular structure of 2,6-dimethyl-3-acetyl-5-carbomethoxy-4- (4′-methoxyphenyl)-1,4-dihydropyridine

2,6-Dimethyl-3-acetyl-5-carbomethoxy-4-(4-methoxyphenyl)-1,4-dihydropyridine has been synthesized and characterized by X-ray diffraction analysis. The compound crystallizes in the monoclinic space group P2 ₁/c with cell parameters a=16.085(2) Å, b= 12.332(3) Å, c= 8.479(4) Å, = 99.23(8)°, Z=4. The structure exhibits both intra and intermolecular hydrogen bonds. The structure adopts a flat boat conformation in the dihydropyridine ring.     

Structural studies of N-2-(6-picolyl)-N′-tolylthioureas

Reaction of 2-amino-6-picoline with 2-, 3-, and 4-tolyl isothiocyanates produces the three N-2-(6-picolyl)-N-tolylthioureas, 6PicTu2T, 6PicTu3T, and 6PicTu4T. 6PicTu2T is mono-clinic, space group P2₁/n with a = 8.1700(3) Å, b = 25.5840(6) Å, c = 12.6840(5) Å, = 98.8750(16)°, and V = 2619.5(2) ų with Z = 8, for d _calc = 1.305 g/cm³. 6PicTu3T is monoclinic, space group C2/c with a = 23.879(3) Å, b = 6.744(3) Å, c = 17.116(10) Å, = 99.26(4)°, and V = 2720(3) ų with Z = 8, for d _calc = 1.257 g/cm³. 6PicTu4T is triclinic, space group P-1 with a = 8.829(6) Å, b = 8.8950(15) Å, c = 10.495(3) Å, = 68.63(3)°, = 72.19(4)°, = 63.06(4)°, and V = 681.2(5) ų with Z = 2, for d _calc = 1.255 g/cm³. Intermolecular hydrogen bonding involving the thione sulfur and the NH hydrogen and the planarity of the thiourea are affected by the position of substitution on the aryl ring. ¹H NMR studies in CDCl₃ show the NH hydrogen resonance considerably downfield from other signals in the spectrum of each thiourea. The enthalpies of fusion of the present thioureas reflect the extent of intermolecular hydrogen bonding and are compared to other heterocyclic thioureas.     

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.     

Synthesis and crystal structure of 2-benzoyl-4-methyl phenyl benzoate

The crystal structure of the title compound, C₂₁H₁₆O₃, has been determined. The compound crystallizes in triclinic space group PĪ with cell parameters a = 9.2240(9) Å, b = 9.8050(8) Å, c = 10.1610(11) Å, α = 94.749(6)^∘, β = 112.544(4)^∘, γ = 102.145(6)^∘ and Z = 2. The structure exhibits both intra and intermolecular interactions of the type C–H ⋅s O. The intermolecular interaction between the molecules form centrosymmetric dimers.     

Structure of 2-{2-[3-methyl-3-(2,4,6-trimethylphenyl) cyclobutyl]-2-oxoethyl}isoindole-1,3-dione

2-{2-[3-Methyl-3-(2,4,6-trimethylphenyl)cyclobutyl]-2-oxoethyl}isoindole-1,3-dione (C₂₄ H₂₅NO₃) was synthesized, and its crystal structure was determined by X-ray crystallographic techniques. The compound crystallizes in the triclinic space group P-1, with unit cell parameters: a = 14.109(9) Å, b = 14.130(8) Å, c = 12.152(6) Å, = 105.62(5)°, = 113.75(4)°, = 98.78(5)°, V = 2039.8(19) ų, D _c= 1.223 g/cm³, and Z = 4. The crystal structure has two crystallographically independent molecules, I and II. These molecules are held together by weak intermolecular C—H···O interactions, forming a continuous chain. The dihedral angles between the N-substituted phthalimide moiety and cyclobutane ring in molecules I and II are 60.37(14) and 68.18(18)°, respectively.     

Crystal structure of benzimidazolium dichromate

The X-ray crystal structure of benzimidazolium dichromate is determined. The compound C₁₄H₁₄Cr₂N₄O₇ is Triclinic in P-1 with a = 8.2722(8) Å, b = 10.0269(10) Å, c = 11.7001(11) Å, = 102.073(2)°, =100.483(2)°, = 67.288(2)°, V = 869.88(15) ų, D _calc = 1.734 g/cm³, and Z = 2. A dichromate ion connects two benzimidazolium rings via hydrgen bonds, as leads to face-to-face intramolecular aromatic stacking. The major force of crystal formation comes from hydrogen bonds, and an intermolecular hydrogen bridge is formed to connect two neighbored dichromate ions.     

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.     

Molecular structures of M(tfac)3 (M=Al, Co) and Cu(H2O)(fod)2: Examples of unusual supramolecular architecture

The molecular structures of Al(tfac)₃ (1), Co(tfac)₃ (2) (H-tfac = 1,1,1-trifluoroacetylacetone) and Cu(H₂O)(fod)₂ (3) (H-fod = 1,1,1,2,2,3,3-hepta-fluoro-7,7-dimethyloctane-4,6-dione) have been determined. The metal coordination spheres in compounds 1 and 2 are essentially the same as the respective M(acac)₃ derivatives. Despite the isomorphous nature of the structures of compounds 1 and 2, the identity of the nearest intermolecular van der Waals contacts are altered by minor changes in the metal coordination sphere. The geometry about copper in compound 3 is close to that of an ideal square bipyramid with the -diketonate ligands occupying the basal plane. The water ligand in each molecule of compound 3 is hydrogen bonded to an oxygen of a -diketonate ligand on an adjacent molecule resulting in the formation of dimers, which form rods along the y-axis due to weak C–F···Cu interactions. Crystal data: (1) orthorhombic, Pca2₁, a = 14.949(3), b = 19.806(4), c = 13.624(3) Å, V = 4033(1) ų, and Z = 8, and (2) orthorhombic, Pca2₁, a = 14.930(3), b = 19.620(4), c = 13.540(3) Å, V = 3966(1) ų, and Z = 8,; (3) monoclinic, P2₁/c, a = 12.447(3), b = 10.486(2) c = 21.980(4) Å, = 102.65(3)°, V = 2799(1) ų, and Z = 4.     

Synthesis and X-ray structure analysis of benzoic acid [1-(6-methyl-2,4-dioxo-3,4-dihydro-2H-pyran-3-yl)eth-(E)-ylidene]-hydrazide with a water molecule (C15H14N2O4?H2O)

The crystal structure of the title compound has been determined by X-ray diffraction methods. It crystallizes in the monoclinic space group P2₁/n with cell parameters a = 7.097(1) Å, b = 19.257(1) Å, c = 10.893(1) Å, = 106.17(2), V = 1429.8(3) ų and Z = 4. The final reliability index is 0.059 for 2419 observed reflections. The molecule comprises of two six- membered rings which are abridged together through a network of C–N, N–N and C–N bonds. There are three keto functional groups and two methyl groups at various locations of the molecule. The C9 atom of methyl group and O2 of the keto group are deviated significantly from the mean plane of the molecule. Both the six-membered rings are planar and it is evident from the magnitude of their exocyclic torsion angles. The molecular structure is stabilized by few intra and intermolecular hydrogen bonds.     

Intra- versus intermolecular hydrogen bonds in salicylamide derivatives

The crystal structures, solid-state infrared patterns, and thermal properties of two polymorphs of 4-nitrosalicylanilide are presented. In both polymorphs, intramolecular hydrogen bonds are found between the phenol oxygen and the amide proton, and intermolecular hydrogen bonds are found between the amide carbonyl oxygen and the phenol proton. These hydrogen bond patterns are compared to those found in other known salicylamide derivatives and an analysis is given of the factors contributing to preferences for intra- or intermolecular hydrogen bonds in these structures. Crystal data: polymorph, orthorhombic,Pbca,a=11.003(4),b=27.959(7),c=7.622(5) Å,Z=4,V=2345(3) ų, andR=0.038 (1351 reflections); polymorph, monoclinic,P2₁/a,a=28.36(1),b=11.64(1),c=7.293(8) Å,=90.68(6)°,Z=8,V=2408 ų, andR=0.043 (2425 reflections).     

Synthesis and crystal structure of 2-anilino-6<Emphasis Type="Italic">H</Emphasis>-5-(1-phenyl-3-methyl-5-pyrazolone-4-ylene)-1,3,4-thiadiazine

A novel pyrazolone derivative 2-anilino-6H-5-(1-phenyl-3-methyl-5-pyrazolone-4-ylene)-1,3,4-thiadiazine (PMCP-PTSC) containing NNS hexa-atomic heterocycle has been obtained and characterized by means of single crystal X-ray diffraction, IR and ¹H NMR spectroscopies. It is interesting that when grown from two different solvents, two different crystalline structures are formed. The monoclinic crystal A belongs to a P2₁/c space group. The unit cell parameters are a = 16.414(4) Å, b = 12.530(3) Å, c = 8.432(1) Å, = 91.75(2) Å, and Z = 4. The triclinic crystal B belongs to a P space group. The unit cell parameters are a = 11.386(2) Å, b = 12.326(2) Å, c = 12.411(3) Å, = 83.07(1)°, = 87.76(2)°, = 86.52(2)°, and Z = 4. The structure analyses show the title compound is the keto-form. Dimers in crystal packing of A and supramolecular one-dimensional (B) concatenate structures were assembled by the intermolecular hydrogen bonds.     

The synthesis and structural characterization of silyl-substituted fluorenes

Three silyl-substituted fluorenes have been prepared by direct synthetic methods and structurally characterized by X-ray diffraction. The three silyl-substituted fluorenes studied were 9-trimethylsilylfluorene (1), 9-(tert-butyldimethyl)silylfluorene (2), and 2,7-di-tert-butyl-9-trimethylsilylfluorene (3). Complex 1 is orthorhombic, P2₁2₁2₁, a = 6.2681(14) Å, b = 14.329(3) Å, c = 15.231(4) Å, Z = 4. Complex 2 is monoclinic, P2₁/c, a = 12.1953(10) Å, b = 6.9977(6) Å, c = 19.6536(17) Å, = 93.818(2), Z = 4. Complex 3 is monoclinic, P2₁/c, a = 11.9954(9) Å, b = 9.8978(7) Å, c = 18.5464(13) Å, = 92.456(2), Z = 4. The long carbon–silicon bonds effectively remove any significant intramolecular interactions as little distortion is exhibited around the sp ³-carbon atom and the fluorenyl backbone demonstrates near planarity. The bulky silicon substituents also prevent intermolecular interactions, as only a few close contacts less than 4.0 Å exist in all three solid state structures.     

Crystal structure of [RuCl2[N-(2,4,6-trimethyl-benzyl)N-(n-butyl)]-imidazolidin-2-ylidene] and [RuCl2[N-(2,4,6-trimethyl-benzyl)-N-(2-methoxyethyl)]-imidazolidin-2-ylidene]

Two imidazolidin ruthenium complexes, [RuCl₂{[N-(2,4,6-trimethyl-benzyl)-N-(n-butyl)]-imidazolidin-2-ylidene}], 1, and [RuCl₂{[N-(2,4,6-trimethyl-benzyl)-N-(2-methoxyethyl)]-imidazolidin-2-ylidene}], 2, have been synthesised and their crystal structures have been determined from single crystal X-ray diffraction data. Compound 1 is monoclinic, of space group C2/c with a = 18.466(4) Å, b = 14.816(3) Å, c = 15.413(3) Å, β = 118.067(2)^∘, and V = 3720.9(12) ų with Z = 8 for d_calc = 1.536 g/cm³. Compound 2 is monoclinic, of space group P2₁/c with a = 8.1800(5) Å, b = 14.344(8) Å, c = 14.809(9), β = 91.604(10)^∘, and V = 1736.7(18) ų with Z = 4 for d_calc = 1.653 g/cm³. In each complex the ligand functions as an arene and carbene, occupying four coordination sites. The two chlorines in each compound complete a distorted octahedron.     

Synthesis and crystal structure of N-(1-phenyl-3-methyl-4-benzal-pyrazolone-5)- N′-salicylidene hydrazine

A novel Schiff base compound, N-(1-phenyl-3-methyl-4-benzal-pyrazolone-5)-salicylidene hydrazine (PMBP-SAH), has been synthesized and characterized by X-ray diffraction: monoclinic, space group C2/c with a = 21.796(5) Å, b = 18.370(3) Å, c = 20.843(3) Å, = 95.440(10)°, V = 8308(3) ų, and Z = 16. The title compound contains two kinds of tautomers: the red compound is the keto form and the other is the enol form. Changes in color are due to the isomerization of the enol and keto forms by the intramolecular proton transfer.     

Crystal structure of bis(2,3,5-trimethylpyridine N-oxide) 2,4,6-trinitrophenolate: Cation complex tied by the extremely strong OHO hydrogen bonding

The salt of bis(2,3,5-trimethylpyridine N-oxide) 2,4,6-trinitrophenolate, C₂₂H₂₅N₅O₉, crystallizes in monoclinic space group C2/c with a=12.411(2)Å, b=15.326(3)Å, c=13.559(3)Å, =113.13(1)°, V=2371.8(8)ų, Z=4, D _c=1.410 mg/m³, F(000)=1056. The molecule of 2,3,5-trimethylpyridine N-oxide is protonated. Two pyridine N-oxide molecules are linked by extremely strong OHO hydrogen bonding (2.378(4)Å) to form a cation complex. CHO hydrogen bonding and – interactions also play important role in stablizing the structure of the salt.     

2-[(trifluoroacetyl)amino]benzoquinone and the hydrochloride and perchlorate salts of 2-aminohydroquinone

Hydrogen bonding parameters for the title materials are reported. 2-[(trifluoroacetyl)amino]benzoquinone crystallizes in the monoclinic space group P2 ₁/c, with a = 18.195(4), b = 5.110(1), c = 9.635(2), = 104.22(3)°, V = 868.4(3) ų, and Z = 4. This compound exhibits two weak intramolecular hydrogen bonds. The first is between a hydrogen atom of the quinone ring and the carbonyl oxygen of the trifluoroacetamide group; it has a distance of 2.24 Å and a C—HsO angle of 122°. The second is between the hydrogen atom of the trifluoroacetamide group and a quinone carbonyl group; it has a distance of 2.26 Å and a N—HsO angle of 107°. 2-Aminohydroquinone hydrochloride crystallizes in the orthorhombic space group Pca2₁, with a = 16.220(3), b = 5.211(1), c = 8.719(2), V = 737.0(2) ų, and Z = 4. 2-Aminohydroquinone perchlorate crystallizes in the orthorhombic space group P2₁2₁2₁, with a = 7.110(1), b = 7.139(1), c = 18.043(4), V = 915.8(3) ų, and Z = 4. All active hydrogens of the two salts exhibit intermolecular hydrogen bonds that serve to organize a three-dimensional framework for each case.     

Crystal structure of a novel inner salt 4-guanidino-2-hydroxybenzoic acid

The guanidinium compound 4-guanidino-2-hydroxybenzoic acid, crystallizes in the orthorhombic space group Pbac with a = 8.090(2) Å, b = 12.470(3) Å, c = 16.430(3) Å, and Φ_calc = 1.564 Mg/m³ for Z = 8. The three-dimensional network is constructed through hydrogen bonds, electrostatic interactions and weak π–π stacking interaction among the guanidinium, carboxyl and hydroxy groups in the title compound.     

Structure of hexakis(imidazole)cadmium(II) carbonate trihydrate: [Cd(Im)6]CO3 ⋅ 3H2O

The crystal and molecular structure of the title compound [Cd(Im)₆]CO₃ 3H₂O, where Im = imidazole, has been determined by X-ray crystallography. The crystal structure consists of discrete Cd(Im)₆ ²⁺ cations, CO₃ ^2– anions and three uncoordinated water molecules. It crystallizes in the hexagonal system, space group P6₃/m, with lattice parameters a = 9.0552(l) Å, c = 21.745(l) Å, and Z = 2; The Cd(II) ion assumes centrosymmetric octahedron geometry. The bond distance of Cd–N is 2.361(l) Å. A three-dimensional intermolecular hydrogen bond network is formed between the free carbonate anions, the imidazole ligands, and the free water molecules.