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.     

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).     

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.     

A structural study on gallium and indium β-diketonates

In an attempt to prepare pentacoordinate chlorobis(-diketonato) gallium(III) and indium(III) complexes only the corresponding tris-products, Ga(PhCOCHCOPh)₃ (1), Ga(^tBuCOCHCO^tBu)₃ (1a), and In(PhCOCHCOPh)₃ (2), could be isolated. The crystal and molecular structures of 1 and 2 were determined. Both the complexes were found to have triclinc crystal system, with P1 space group. Cell parameters: 1 – a = 9.913(3) Å, b = 10.534(6) Å, c = 18.05(2) Å, = 93.86(5)°, = 94.40(4)°, = 106.58(4)°, V = 1805(2) ų, z = 2; 2 – a = 10.507(3) Å, b = 11.448(3) Å, c = 16.322(4) Å, = 107.38(2)°, = 97.38(2)°, = 102.23(2)°, V = 1792(1) ų, z = 2.     

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.     

Preparation and crystal structures of the Ce(IV) β-diketonates, [Ce(tmhd)4] and [Ce(pmhd)4] (tmhd =2,2,6,6-tetramethylheptane-3,5-dionate and pmhd = 1-phenyl-5-methylhexane-1,3-dionate)

The cerium(IV) -diketonate compounds [Ce(-diket)₄] [where -diket = tmhd (2,2,6,6-tetramethylheptane-3,5-dionate) 1, pmhd (1-phenyl-5-methylhexane-1,3-dionate) 2] were prepared by reacting cerium(IV) ammonium nitrate [CAN; Ce(NH₄)₂(NO₃)₆] with the respective Na(-diket) compound in ethanol, and structurally characterized by single crystal X-ray diffraction. Compound 1 crystallizes in the triclinic space group with a = 12.472(4), b = 19.972(5), c = 21.436(3) Å, = 97.05(7), = 90.16(2), = 106.55(3)°, V = 5076(2) ų, Z = 4, T = 150(2) K. Compound 2 crystallizes in the monoclinic space group P2₁/n. with a = 14.817(6), b = 17.123(6), c = 19.146(3) Å, = 105.46(4)°, V = 4682(3) ų, Z = 4, T = 150(2) K. Crystals of 1 contain two independent [Ce(tmhd)₄] molecules, with four chelating tmhd ligands bonded to each metal in a distorted dodecahedral arrangement; the cerium atom in 2 is also bonded to four chelating pmhd ligands but in this case the coordination geometry is closer to square antiprism. Both complexes are air and moisture stable. Sublimation studies reveal that 1 sublimes almost quantitatively, while 2 is comparatively involatile.     

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.     

Structural characterization of Elisabatin B and Elisabatin C

X-ray structures of Elisabatin B (1) and Elisabatin C (2) have been determined. Crystal data for 1: Triclinic, P (No. 2), a = 7.528(2) Å, b = 9.404(2) Å, c = 11.414(2) Å, = 75.363(3)°, = 86.668(4)°, = 89.683(4)°, and Z = 2. Crystal data for 2: Monoclinic, P2₁/c (No. 14), a = 8.242(2) Å, b = 14.870(2) Å, c = 13.060(2) Å, = 101.458(3)°, and Z = 4. Both compounds are highly unsaturated leading to extended aromatic conjugation. They show different intermolecular O–HO hydrogen bonds, via which 1 forms dimers, and 2 zig-zag polymeric chains.     

Crystal structures of a series of 3,8-di[-2-aryl-1-azenyl]-1,3,6,8-tetraazabicyclo[4.4.1]undecanes

The crystal and molecular structure of a series of 3,8-di[-2-aryl-1-azenyl]-1,3,6,8-tetraazabicyclo[4.4.1]undecanes (1–5) have been determined by single crystal X-ray diffraction analysis. In all five compounds, the tetraazabicycloundecane portion of the molecule assumes a cage-like, folded structure with the aryltriazene moieties aligned approximately parallel; the structure is held in the folded configuration by either intramolecular or intermolecular – stacking forces. Crystal data: 1 C₁₉H₂₂N₁₀O₄, monoclinic space group P2₁/c, a = 10.1846(7), b = 9.9556(7), c = 20.819(2) Å, = 98.725(1)°, V = 2086.5 (3) ų, Z = 4; 2 C₂₃H₂₈N₈O₄, triclinic, space group P, a = 6.7064(7), b = 12.9662(14), c = 14.054(2) Å, = 94.796(2), = 91.621(2), = 104.836(2)°, V = 1175.7(2) ų, Z = 2; 3 C₁₉H₂₂N₁₀O₄, monoclinic, space group P2₁/c, a = 14.237(2), b = 13.520(2), c = 11.5805(12) Å, = 113.514(2)°, V = 2044.0(4) ų, Z = 4; 4 C₂₁H₂₂N₁₀, monoclinic, space group C2/c, a = 54.247(3), b = 11.5531(7), c = 12.9670(7) Å, = 95.710(1)°, V = 8086.4(8) ų, Z = 16; 5 C₂₅H₃₂N₈ 0₄, monoclinic, space group P2₁/c, a = 10.2908(7), b = 16.5687(12), c = 15.1662(10) Å, = 94,188(1)°, V = 2579.0(3) ų, Z = 4.     

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.     

Unique assemblies of alternating positively and negatively charged layers, directed by hydrogen bonds, ionic interactions, and π-stacking in the crystal structures of complexes between mellitic acid (benzenehexacarboxylic acid) and five planar aromatic bases

Benzenehexacarboxylic acid, mellitic acid (MA), has been used as a core motif to study possible radial self-assembly using complementary aromatic bases. By mixing water solutions of the components, crystals of the salts of MA with 4-aminopyridine (AP), 4-dimethylamino-pyridine (DM), 2,2-bipyridine (DP), o-phenanthroline (PL), and melamine (ML) have been obtained. The MA^–n ions have assembled in either extended sheets for MA^–2 or extended ribbons for MA^–4 by direct hydrogen bonding between MA and MA and additionally through mediation of hydrogen bonds to water molecules that distribute the negative charges throughout the MA sheet or ribbon. Most of the O atoms in carboxyl groups in the MA ions in the five complexes have been rotated significantly out of the plane of the central benzene ring. There are multiple base molecules, two or four, for each mellitic acid ion in the five complexes. Most of the NH⁺ moieties in all five bases make direct NH⁺ O–C hydrogen bonds with MA^–n . The planar base ions are generally arranged in stacks in which the components range from being parallel, with interplanar separations of 3.5 Å, to having a considerable tilt with respect to each other with nearest interplanar separation of atoms greater than 3.9 Å. These geometric characteristics are reflected in the color of the crystals. The three-dimensional networking makes some of the crystals very hard. Cell dimensions: 1, C₃₂H₃₀N₈O₁₂ 2H₂O, C2/c, a =13.764(2) Å, b =18.053(3) Å, c =14.876(4) Å, =105.99(2)° 2, C₂₆H₂₆N₄O₁₂ 3H₂O, P2₁/n, a =15.891(1) Å, b =10.444(1) Å, c =18.242(1) Å, =97.00(1); 3, C₆₄H₄₄N₈O₂₄ 7H2O, P2₁/c, a =23.016(4) Å, b =15.241(2) Å, c =19.124(2) Å, =100.60(1)° 4, C₃₆H₂₂N₄O₁₂, P2₁/n, a =14.581(1) Å, b =10.472(1) Å, c =20.607(2) Å, =106.43(1); 5, C₁₈H₁₈N₁₂O₁₂ 2H₂O, , a =8.257(2) Å, b =8.986(2) Å, c =9.383(1) Å, =98.60(1)°, =96.38(2)°, =117.07(1)°.     

fac-Re(bpy)(CO)3(COOMe): A model metallocarboxylate complex of rhenium with a bipyridyl ligand

The title compound, fac-(2,2-bipyridyl)(carbomethoxy)rhenium tricarbonyl, crystallizes in the monoclinic system, space group P2₁/c with the following crystal data: a = 8.37551(1), b = 6.6934(1), c = 26.2098(1) Å, V(ų) = 1535.93(3), Z = 4, and = 90.0971(2). The metal environment is slightly distorted octahedral with a chelating bipyridyl ligand and a facial arrangement of the carbon monoxide ligands.     

Supramolecular structure of tetrakis-μ-(4-chloro-3-nitrobenzoato)-bis(methanol)dicopper(II)

The title compound, [Cu₂(II)(4-Cl-3-NO₂–C₆H₃CO₂)₄(CH₃OH)₂] or [Cu₂(4-chloro-3-nitrobenzoate)₄(MeOH)₂] has been prepared and its structure determined using X-ray crystallography. The complex crystallizes in the triclinic space group P-1 with a = 9.6887(9)Å, b = 10.6448(9)Å, c = 11.4194(10)Å, = 108.094(2), = 110.682(2), = 105.055(2), V = 952.691(15)ų, and Z = 1. The structure consists of centrosymmetric dimers in which the Cu(II) atoms display a square pyramidal CuO₅ coordination, with four carboxylate O atoms in the basal plane [CuO 1.951(2)–1.968(2)Å] and the methanol O atoms in the apical position [CuO 2.170(2)Å]. The Cu atoms are 2.614(1)Å apart and are bridged by four benzoate groups. The discrete dimers are extended into 1D chains that result from hydrogen bonding between the coordinated methanol on one Cu(II) dimer and the nitro substituent on an adjacent Cu(II) dimer. The chains are interdigited and held by – stacking interactions forming 3D supramolecular array.     

Molecular and crystal structure of two nickel(II) 1,2-dithiooxalato-S,S′ complexes using 1-(Rbenzyl)pyridinium cation (R = 4′-bromo-2′-fluoro or 4′-bromo)

[BrFPy]₂[Ni(dto)₂] (1) and [BrPy]₂[Ni(dto)₂] (2) complexes have been prepared by reaction of Na₂[Ni(S₂C₂O₂)₂] and the corresponding 1-(Rbenzyl)pyridinium bromide salt (R₁ = 4-bromo-2-fluoro, R₂ = 4-bromo). The crystallographic data for 1: monoclinic P2₁/c, a = 14.2192(1) Å, b = 14.2533(4) Å, c = 15.6535(3) Å, = 96.463(1)°, V = 3152.34(11) ų, Z = 4. Two cations, [Br₁F₁Py]⁺ and [Br₂F₂Py]⁺, both adopt a conformation where both the aromatic rings are twisted to the corresponding N(1)–C(10)–C(11) or N(2)–C(22)–C(23) reference plane. Data for 2: triclinic , a = 9.4042(3) Å, b = 9.6814(4) Å, c = 10.3357(4) Å, = 80.155(1)°, = 65.245(1)°, = 64.259(1)°, V = 769.68(5) ų, Z = 1. The [Ni(dto)₂]^2– anion exhibits a quasi-planar structure in both complexes. An extensive hydrogen bond network of C–H O is clearly observed in 1 and 2, and two complexes show similar crystal packing.     

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.     

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.     

Synthesis and X-ray structure of p-tolyl phenylthioglyoxylate

The title compound (C₁₅H₁₂O₂S) is triclinic witha=7.077(10),b=8.825(2),c=11.068(2) Å, =106.66(3)^o, Z=2, and space group P. The significant structural features lies in the two carbonyl groups of the thioglyoxylate which are oriented antiperiplanar to each other [–168.2(2)^o]. The central C(8)–C(9) bond is 1.553(3) Å. The phenyl rings are twisted with respect to the carbonyl groups. Short contacts are present between S and O(1) [2.652(2) Å] and also between S and O(2) [2.758(2) Å].     

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 Al(tBu)3(NH2CH2CH2Ph): A molecular “slinky”

The molecular structure of Al(^tBu)₃(NH₂CH₂CH₂Ph) is determined by the crystal packing of the phenyl rings and the pseudo spherical Al(^tBu)₃ units, and may be viewed as a layered structure consisting of double sheets of the phenyl rings and the Al(^tBu)₃ units. The Al–N–C–C linkage shows severe disorder as a result of its flexibility. The structure of Al(^tBu)₃ (NH₂CH₂CH₂Ph) can be likened to a molecular slinky, in which the rigid ends are fixed in space by molecular packing forces, leaving the interior link to adopt multiple orientations. Crystal data: orthorhombic, Cmca,a=13.282(9),b=25.01(1),c=13.210(9), Å,V=4388(10) ų,Z=4,R=0.0957,R _w=0.0957.     

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.