Synthesis, characterization, peripheral studies, and structural analysis of E-4-(N-methylanilino)-3-pentene-2-one, C12H15NO

Crystallographic structural refinement of E-4-(N-methylanilino)-3-pentene-2-one (I) has been carried out by means of three-dimensional single-crystal X-ray diffractometry. The title compound crystallizes in space group C2 (No. 5,Z = 4). The lattice constants are a = 21.543(4), b = 6.433(1), c = 8.019(2) Å, and = 97.82(3)°. Characterizations include physical property determinations and spectrometric identifications employing IR, ¹H and ¹³C NMR, and X-ray powder analyses. The molecules in the crystal lattice are held together by van der Waals forces. Selected bond distances and angles are presented and discussed as well as synthesis and peripheral studies.     

The crystal structures of two reaction products of α-halopyruvamide with nitrogen and sulfur nucleophiles

Two compounds have been prepared during the investigation of the reactivity of -halopyruvamides. The reaction products: 3-(4-chlorophenyl)imidazo[1,2-a]pyridine-2-carboxamide (1) and 7-carbamoyl-5-phenyl-2,3-dihydro[1,3]thiazolo[4,3-b][1,3]thiazol-4-ium chloride (2) were structurally characterized by x-ray crystallography. Compound 1 crystallizes in the orthorhombic space group Pca2₁ with a = 28.813(2), b = 9.369(1), and c = 9.361(1) Å. The structure contains two crystallographically different molecules. Compound 2 crystallizes in the monoclinic space group P2₁/c with the following cell parameters: a = 8.5895(8), b = 22.499(2), c = 7.4133(6) Å, and = 110.204(1)°.     

Synthesis,thermal reactivity and structure of 1,2-bis(4-hydroxy-3-methoxyphenylethynyl)benzene

The crystal structure of the new enediyne 3 was determined by X-ray diffraction. 3 crystallizes in the orthorhombic space group Pbca (No. 61) with a = 12.7148(9) Å, b = 7.4872(8) Å, c = 38.890(4) Å, = = = 90 and Z = 8. The three-dimensional structure is characterized by an 8-membered cyclic array linking four molecules of 3 by hydrogen bonding between phenolic and methoxy groups. Furthermore, stabilization by –-stacking and CH s interactions is present. The important cd distance (between the two terminal acetylene carbons of the enediyne) which is relevant for the Bergman cyclization, was determined to 401 pm, being in good agreement with the high cyclization barrier ( G = 147.9 kJ mol^–1 at 220C) that was determined by differential scanning calorimetry (DSC).     

Crystal structures of bis(4-dimethylaminopyridinium) tetrachlorocobaltate(II) and bis-[1,3-di (ammoniummethyl)benzene]tetrachlorocobaltate(II)

The crystal structures consist of organoammonium cations hydrogen bonded to tetrahedral CoCl₄ ^2– anions. In the 4-dimethylaminopyridinium salt, [(CH₃)₂NC₅H₅NH]₂CoCl₄, pairs of cations hydrogen bond in an asymmetric fashion to two of the chlorines in each anion. The planar cations form two sets of – stacks, first parallel to the a axis and the second parallel to the b axis. The anions lie between these two nonintersecting sets of stacks. In contrast, for the second compound, [C₆H₄(CH₂NH₃)₂]CoCl₄, the tetrahedral CoCl₄ ^2– anions form layers lying parallel to the bc plane. The 1,3-di(ammoniummethyl)benzene cations crosslink adjacent anionic layers, forming a lamellar structure of alternating organic and inorganic layers.     

Crystal and molecular structure of a nickel(II) complex with a macrocyclic [14]N4 ligand

The crystal and molecular structure of a macrocyclic oxamido Schiff base Ni(II) complex [NiL] has been determined by X-ray crystallography. L is the dianion of diethyl 5,6,7,8,15,16-hexahydro-6,7-dioxodibenzo[1,4,8,11]tetraazacyclotetradecine-13,18-dicarboxylate. Ni(II) is located in the coordination cavity formed by the four nitrogen donors of the deprotonated macrocyclic oxamido ligand with a distorted square-planar geometry. C–H O hydrogen bonds have been observed in the crystal. The macrocyclic complex crystallizes in the triclinic space group P – 1, with lattice parameters a = 7.977(3) Å, b = 12.581(4) Å, c = 12.679(4) Å, = 112.669(6)°, = 96.849(7)°, = 106.204(7)°, V = 1089.9(6) ų, Z = 2.     

The crystallographic structure of a novel camphanic amide

The crystallographic structure of a novel camphanic amide 5 is disclosed by x-ray analysis. It crystallized in the space group P2₁2₁2₁(#19) with a = 15.663(3), b = 17.848(3), c = 7.935(8) Å, V = 2209.5(6) ų, Dcalc = 1.165 g/cm³, and Z = 4.     

Molecular structures of (tBu)Ga(S2CNnPr2)2 and (iPrO)Ga(S2CNEt2)2: An example of an unusual ligand pseudorotation

The molecular structures of (^tBu)Ga(S₂CNⁿPr₂)₂ (1) and (ⁱPrO)Ga(S₂CNEt₂)₂ (2) have been determined. The variation in the geometries observed for bis-dithiocarbamate compounds of gallium, (X)Ga(S₂CNMe₂)₂ (X=Cl, ⁱPrO, ^tBu) do not lie along the Berry pseudorotation pathway for the square-based pyramid to trigonal bipyramid geometrical transition. Instead, the structures appear to lie on an unusual ligand two-step, Texas, pseudorotation mechanism which results in a highly distorted trigonal bipyramidal geometry. Crystal data: (1) monoclinic, P2₁,/c, a = 9.786(1), b = 29.218(3), c = 9.452(1) Å, = 108.379(9)°, V = 2564.7(5) ų, and Z = 4. (2) Monoclinic, P2₁ /c, a = 10.980(3), b = 15.673(4), c = 12.461(3) Å, = 97.47(2)°, V = 2126.2(9) ų and Z = 4.     

Distortions of molecular geometry in pentafluorophenyl rings bonded to metals

The variance in the geometry of pentafluorophenyl rings bonded to metals of the fourth, fifth and sixth rows of the Periodic Table has been analyzed from the data present in the literature. The application of univariate and bivariate analysis to internal coordinates shows that the major variation corresponds to bond angles, specially to those near to the substitution. This effect (ipso effect) seems to be related to the Pauling's electronegativity of the metals. Multivariate analysis of these coordinates reveals the existence of three principle effects, the main one of them corresponding to the ipso effect and the other two being related with the thermal vibration of the molecule and with the inhomogeneity of the sample. The application of bivariate analysis to symmetry coordinates does not give any correlation between the two orthogonal components describing fully the angular variance.     

Chemical preparation and crystal structure of 6′-butoxy-2,6-diamino-3,3′azo-dipyridine monohydrate

Chemical preparation, X-ray single crystal, and calorimetric studies of C₁₄H₁₈N₆O·H₂O are described. The compound crystallizes in the triclinic space group, P with unit cell dimensions: a = 6.2640(3), b = 10.9840(4), c = 12.2220(3) Å, = 105.03(2), = 96.96(2), = 101.6(2)°, V = 712.10(5) ų, and Z = 2. The 6-butoxy-2,6-diamino-3,3-azo-dipyridine monohydrate structure is built up from organic layers parallel to the (120) plane linked via O—H···N bond.     

X-ray elucidation of 17α-pregna-2,4-dien-20-yne-(2,3-d) isoxazole-17β-ol

Synthetic pregnen steroid 17-pregna-2,4-dien-20-yne-(2,3-d) isoxazole-17-ol crystallizes in the orthorhombic space group P2₁2₁2₁, with a = 6.601(4), b = 10.530(4), c = 26.177(9) Å, and Z = 4. The structure was solved from Enraf Nonius CAD4 diffractometer data by direct methods and refined to R = 0.0399 for 2041 observed reflections (I > 2(I)). The molecule contains five rings of which rings A, B, and C are cyclohexene; ring D is cyclopentene; and ring E is heterocyclic cyclopentene. Ring A acquires the conformation of a half-chair; ring B tends toward a half-chair conformation with a bias toward a chair conformation that contains a hydrogen at C8 and an hydrogen at C9. Ring C acquires a near chair conformation with an hydrogen at C14. Ring D is a 13, 14-half chair, and ring E is a O3-envelope. Both the ring junctions A/B and A/E are quasi-trans, whereas the ring junctions B/C and C/D are both trans. The molecule as a whole is slightly convex toward the -side, with an angle of 16.7(2)° between the C10–C19 and C13–C18 vectors. Structural association is due to hydrogen bonding and stacking interactions.     

The crystal structure of tris(4-methylpyridine) tricarbonylmolybdenum(0)

The title compound, Mo(4-CH₃C₅H₄N)₃(CO)₃, is monoclinic, P2₁/c, with cell dimensionsa=10.385(1),b=13.572(2),c=15.522(2) Å, =105.08(1)°,Z=4. The complex isfac-octahedral with approximate three-fold symmetry. The Mo–C bond lengths are 1.901–1.904(7) Å, distinctly shorter than in the parent Mo(CO)₆, and the Mo–N bond lengths are 2.297–2.331(5) Å.     

Crystal structure of 2-amino-3-methylpyridinium ortho-phthalate

A new crystal of 2-amino-3-methylpyridinium ortho-phthalate has been prepared and characterized by X-ray crystallography. The salt crystallizes in the monoclinic space group P2₁/c with a = 11.015(2) Å, b = 11.057(2) Å, c = 15.767(2) Å, = 90.00°, = 96.220(10)°, = 90.00°, V = 1909.0(5) ų, Z = 4. In the cell unit, the phthalate anion is linked with two pyridinium cations by NHO hydrogen bond on both sites of annular and exocyclic nitrogen atoms. The two pyridinium cations are arranged in a face-to-face pattern with a dihedral angle of 7.3° and a shortest aspectant distance of 3.4(1) Å between them, indicating the existence of – interaction. The C(5) atom is an electron donating center. The exocyclic N atom is an electron receiving center, which is consistent with features of imino resonance evidenced by bond lengths and angles. In the cell unit, two entities of pyridinium cation are aligned with each other in a face-to-face manner of electron receiving to donating center.     

Crystal structures of 4,7-phenanthrolino-5,6:5′,6′-pyrazine tetrahydrate and 1,4,5,8,9,12-hexaazatriphenylene dihydrate

The crystal structures of 4,7-phenanthrolino-5,6:5,6-pyrazine tetrahydrate (I) and 1,4,5,8,9,12-hexaazatriphenylene dihydrate (II) have been determined from low temperature (173 K) x-ray single crystal diffraction data. I crystallizes in the triclinic system, space group P with a = 11.2687(6), b = 12.4766(6), c = 12.7068(7) Å, = 113.4740(10), = 91.605(2), = 114.587(2)°, V = 1449.33(13) ų, and Z = 4. II crystallizes in the orthorhombic system, space group Pca2₁ with a = 18.187(2), b = 9.2576(11), c = 6.9672(8) Å, V = 1173.0(2) ų, and Z = 4. In both structures the planar heterocyclic molecules stack with interplanar distances down to 3.3 Å, which is consistent with self--complexation. The crystal water molecules provide links between the columns of stacked molecules through hydrogen bonds. In each compound the N-C bond lengths fall into two distinct groups (mean values 1.330(3) vs 1.361(1) Å in I and 1.320(3) vs 1.357(5) Å in II), as do the C-C bonds of the central phenyl rings (1.411(4) vs 1.467(1) Å in I and 1.405(5) vs 1.458(4) Å in II).     

Synthesis and crystal structure of 7-ethoxyl-4′-hydroxyisoflavone

7-Ethoxyl-4-hydroxyisoflavone was prepared and its crystal structure was examined by X-ray diffraction. Crystallization of the title compound occurs in the monoclinic, space group P2(1)/c with a = 11.144(2) Å, b = 10.209(1) Å, c = 13.191(2) Å, = 113.43(1) and Z = 4. The molecular structure of title compound consists of a benzopyranone moiety, a phenyl moiety, a hydroxyl and an ethoxyl group. The benzopyranone ring is not coplanar with the phenyl ring, the dihedral angle being 46.75. The ethoxyl group is nearly coplanar with its corresponding ring with the torsion angle 175.23(2). Three kinds of hydrogen bond and two kinds of aromatic stacking interaction link the title compounds into a three-dimensional networking structure.     

Crystal structure of 1,3-di-2-[(4-methoxyphenyl)-1-diazenyl]imidazolidine

The crystal and molecular structure of 1,3-di-2-[(4-methoxyphenyl)-1-diazenyl]imidazolidine (1) has been determined by single crystal X-ray diffraction analysis. This novel bis-triazene assumes a close-to planar structure with the aryltriazene moieties aligned in diametrically opposed directions, unlike many other previously reported bis-triazenes, which assume a folded structure. The structure of 1 is compared with the closely related, non-cyclic bis-triazene analogue (2), and also compared with the structure of the simple mono-triazene (3). Crystal data: 1 C₁₇H₂₀N₆O₂, monoclinic, space group C2/c, a = 34.948(3), b = 5.925(5), c = 8.1225(6) Å, = 100.8420(10)°, and V = 1652.0(2) ų, for Z = 4.     

Six-coordinated zinc complexes: [Zn(H2O)4(phen)] (NO3)2·H2O and [ZnNO3(H2O)(bipy)(Him)]NO3 (phen = 1,10-phenanthroline, bipy = 2,2′-bipyridine, and Him = imidazole)

Two novel six-coordinated zinc complexes, tetra-aqua(1,10-phenanthroline)zinc dinitrate monohydrate, [Zn(H₂O)₄(phen)](NO₃)₂·H₂O (1) and aqua(2,2-bipyridine)(imidazole)-nitratozinc nitrate, [ZnNO₃(H₂O)(bipy)(Him)]NO₃ (2) were prepared. Compound 1 crystallizes in the monoclinic space group P2₁/c with a = 8.780(4), b = 13.609(4), c = 15.368(5) Å, = 93.86(2)°C, V = 1832.1(12) ų. In 1, a phenanthroline molecule chelates the zinc atom and four water molecules complete the octahedral geometry around the metal. Compound 2 crystallizes in the monoclinic space group P2₁/n with a = 7.250(1), b = 24.554(4), c = 10.258(2) Å, = 107.880(10)°, V = 1737.9(5) ų. In 2, a bipyridine molecule and a nitrate anion chelate the zinc atom. An imidazole molecule and a water molecule then complete the six-coordinated geometry around zinc. The intermolecular packing is controlled by hydrogen bonding, especially in 1 and by stacking. The thermal stability of the compounds and the loss of water molecules and ligands was monitored by a thermogravimetric study.     

Synthesis and crystal structure of 1,1′-di(ethylpropionato)-2,2′-biimidazole, a macromolecular precursor

1,1,-Di(ethylpropionato)-2,2-biimidazole, C₁₆H₂₂N₄O₄, crystallizes from ice-cold ethanol in the space group P , with a = 4.6742(9), b = 9.1119(13), c = 10.175(2) Å, = 96.22(1), = 96.29(2), = 97.53(1)°, and Z = 1. The molecule crystallizes with coplanar rings and the substituents assume a trans conformation with a center of inversion between the bridging carbon atoms.     

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.     

Crystal and molecular structure of aqua(2,2′-bipyridine)bis(betaine)copper(II) perchlorate monohydrate

A new monomeric copper(II) complex with 2,2-bipyridine (bpy) and betaine (bet), [Cu(byy)(bet)₂(H₂O)](ClO₄)₂ · H₂O, has been prepared and characterized by X-ray crystallography. The complex crystallizes in the triclinic space groupP-1 witha=8.859(2),b=11.191(2),c=14.850(3) Å, =91.41(1), =97.19(1), =91.97(1)°,V=1459.2(7) ų, andZ=2. The structure comprises discrete cations [Cu(bpy)(bet)₂(H₂O)]²⁺ in which the metal atom is coordinated in a distorted square-pyramidal environment by two oxygen atoms from a pair of monodentate carboxylato ligands [Cu–O=1.950(2) Å] and two nitrogen atoms of a bidentate bpy ligand [Cu–N=1.997(3)–2.005(3) Å] on the basal plane, and one aqua [Cu–O=2.267(3) Å] ligand at the apical position.     

Synthesis and crystal structure of N-<Emphasis Type="Italic">tert-</Emphasis>butyl-N′-thio [O-(1-methylthioethylimino)-N″-methylcarbamic acid]-N,N′-dibenzoylhydrazine

The novel compound N-tert-butyl-N-thio[O-(1-methylthioethylimino)-N-methyl carbamic acid]- N,N-dibenzoylhydrazine has been synthesized by the reaction of N-tert-butyl-N,N-dibenzoylhydrazine with N-sulfenyl chloride of O-(1-methylthio ethylimino) -N-methylcarbamic acid. Its structure was determined by X-ray single crystal diffraction. The crystal belongs to monoclinic, space group P2₍₁₎/n with the following crystallographic parameters: a = 7.569(3) Å, b = 20.585(7) Å, c = 16.347(5) Å, = 90, = 92.606(6), = 90, V = 2544.4(14) ų, z = 4, Dx = 1.276 mg/m³, F(000) = 1032, T = 293(2) K, 2.34 25.01, the final R factor: R₁ = 0.0475, wR₂ = 0.0907. The N–N bond adopts a gauche conformation with a dihedral angle() of 98.8 for C(17)=N(1)=N(2)=C(7), whereas its parent compound N-tert-butyl-N,N-dibenzoyl hydrazine has the dihedral angle of –71.8.