Nepetanudone, a dimer of the α-pyrone 5,9-dehydronepetalactone

The title compound C₂₀H₂₄O₄ crystallizes in the orthorhombic space group P2₁2₁2, with a = 10.245(3), b = 17.103(3), c = 9.879(3) Å, D _c = 1.260 g cm ^–3, and Z = 4. Nepetanudone is postulated to be formed by a [4+4] cycloaddition of two 5,9-dehydronepetalactone moieties to give an asymmetric dimer in which each pair of atoms is magnetically nonequivalent. The compound was recovered from extracts of Nepeta nuda ssp. albiflora.     

X-ray and NMR studies on the rotational isomerism about the C(5)-C(6) bond of 6-substituted methyl 2,3,4,-tri-O-acetyl-6-X-α-D-glucopyranoside derivatives

The rotamers about the C(5)–C(6) bond of a series of 2,3,4-tri-O-acetyl-6-X--D-glucopyranozide derivatives resulting by substitution at C(6) or O(6) have been studies with¹H-NMR spectroscopy (400 MHz) and X-ray structure analysis. The methyl 2,3,4-tri-O-acetyl-6-O-triphenylmethyl--D-glucopyranoside and the N-(I-O-methyl-2,3,4-tri-O-acetyl--D-glucopyranose-6-yl)-pyridinium nitrate crystallize in the P2₁ space group with =14.940(1),b=11.232(1),c=9.0773(7), and =94.480(7) anda=7.670(1),b=15.384(3),c=9.624(1) and =104.90(1), respectively; the methyl 2,3,4-tri-O-acetyl-6-O-nitro--D-glucopyranoside and methyl 2,3,4-tri-O-acetyl-6-O-deoxy-6-iodo--D-glucopyrano-side crystallize in the P2₁2₁2₁ space group witha=5.630(1),b=14.360(1) andc=22.388(3), anda=5.556(1),b=14.303(6) andc=21.963(6), respectively.     

Synthesis and structural characterization of five new coordination polymer chain structures using a new,Z-shaped ligand, 2,2′-bis-(4-pyridylethynyl)tolane

Using the new ligand, 2,2-bis-(4-pyridylethynyl)tolane we have synthesized five new coordination polymers: HgBr₂[2,2-bis-(4-pyridylethynyl)tolane] (1), HgI₂[2,2-bis-(4-pyridylethynyl)tolane] (2), Ni(acetylacetonate)₂[2,2-bis-(4-pyridylethynyl)tolane] (3), Zn(acetylacetonate)₂[2,2-bis-(4-pyridylethynyl)tolane] (4), and Cu(hexafluoro acetylacetonate)₂[2,2-bis-(4-pyridylethynyl)tolane]CHCl₃ (5). 2,2-Bis-(4-pyridyl ethynyl)tolane is a rigid ligand with a Z-shape that promotes the formation of zig-zag chains. Compounds 1– 5 were characterized by single crystal X-ray diffraction; and compounds 1– 3 were additionally characterized by IR, elemental analysis, and thermogravimetric analysis. Compound 1 crystallizes in the monoclinic space group C2/c with a = 29.761(3) Å, b = 5.0531(5) Å, c = 16.7823(15) Å, = 104.090(2), V = 2447.9(4) ų, Z = 4. Each mercury is bound to two tolane ligands and two bromine anions, resulting in a tetrahedral coordination environment. Compound 2 crystallizes in the monoclinic space group P2/c, with a = 20.3061(17) Å, b = 5.6303(5) Å, c = 24.5459(19) Å, = 110.338(2), V = 2631.4(4) ų, Z = 4. Here also, each mercury is bound to two tolane ligands and two iodine anions in a tetrahedral coordination environment. The ligand orientation differs in compounds 1 and 2 being trans oriented in 1 and cis oriented in 2. Compound 3 crystallizes in the monoclinic space group P2₁/c with a = 14.5947(14) Å, b = 6.3082(6) Å, c = 18.3939(18) Å, = 112.112(2), V = 1568.9(3) ų, Z = 2. Each nickel is bound to two tolane ligands and two bidentate AcAc anions, resulting in an octahedral coordination environment. Compound 4, which is isostructural with 3, also crystallizes in the monoclinic space group P2₁/c with a = 14.6990(9) Å, b = 6.2724(4) Å, c = 18.6433(11) Å, = 112.8610(10), V = 1583.86(17) ų, Z = 2. Compound 5 crystallizes in the triclinic space group P-1 with a = 6.5487(4) Å, b = 11.6471(7) Å, c = 14.3225(9) Å, = 70.1360(10), = 89.3990(10), = 88.7680(10), V = 1027.18(11) ų, Z = 1. Each copper in 5 is bound to two tolane ligands and two bidentate hfAcAc anions, resulting in an octahedral coordination environment identical to that found in 3 and 4.     

Synthesis and crystal structure of 1D 2,3-naphtho 15-crown-5 complex [Na(N15C5)]<Subscript>2</Subscript>[Ni(i-mnt)<Subscript>2</Subscript>] containing S⋅<Emphasis Type="Italic">s</Emphasis>C and S⋅<Emphasis Type="Italic">s</Emphasis>π interactions

The reaction of 2,3-naphtho-15-crown-5 (N15C5) with Na₂[Ni(i-mnt)₂] [i-mn = 1,1-dicyanoethylene-2,2-dithiolate] affords the title complex [Na(N15C5)]₂[Ni(i-mnt)₂] (1), which is characterized by elemental analysis, FT-IR, UV-visible spectra and single crystal X-ray diffraction. 1 crystallizes in the triclinic, space group P with a = 8.291(4), b = 12.833(7), c = 12.913(6) Å, = 115.732 (7), = 105.030(7), = 90.912(8), V = 1182.2(10) ų, Z = 1 and R₁(wR₂) = 0.0422(0.1001). The single crystal X-ray analysis shows that the [Na(N15C5)]⁺ complex cations act as the bridges linking the [Ni(i-mnt)₂]^2– anions into a 1D infinite chain through Na–N interactions and SsC and Ss interactions are observed in the chain with the shortest SsC distance of 3.433 Å.     

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.     

C(4) helices,Br⋅<Emphasis Type="Italic">s</Emphasis>Br interaction and <Emphasis Type="Italic">R</Emphasis><Stack><Subscript>4</Subscript><Superscript>2</Superscript></Stack> (10) ring in bromoipriflavone

The title compound, 8-bromo-7-isopropoxyisoflavone (bromoipriflavone), C₁₈H₁₅O₃Br, crystallizes in tetragonal crystal system, space group I4₁/a with cell constants a = 21.396(2) Å, c = 13.588(2) Å, V = 6220.2(14) ų and Z = 16. Bromoipriflavone is composed of a benzopyranone moiety, a phenyl moiety, an isopropoxy group and a bromine atom. The benzopyranone ring is not coplanar with the phenyl ring with a dihedral angle of 55.1. The molecules are stacked into a C(4) helices down [001] via – stacking and hydrogen bonds, the C(4) helices are assembled into three-dimensional network via strong BrsBr interactions and synthons R₄²(10) formed by two tri-centered C–HsO hydrogen bonds, resulting in a distinctive high-symmetry supramolecule. The title compound was also characterized by IR and ¹H NMR.     

Synthesis and crystal structure of [{V3(μ-Cl)4(μ 3-Cl) (μ 3-OH)(thf)2(teeda)}2]·2(thf) (teeda = N,N,N′N′-tetraethylethane-1,2-diamine)

The title complex was prepared from the reaction of [V₂(-Cl)₃(thf)₃]₂[Zn₂Cl₆] with N,N,NN-tetraethylethane-1,2-diamine (teeda) in refluxing thf and its crystal structure exhibits two triangulo-[V₃(-Cl)₃(-Cl)( ₃-OH)(thf)₂(teeda)]⁺ cations bridged by two chlorides. The molecular structure (monoclinic, space group P2 ₁/n, Z = 2, a = 11.8005(7) Å, b = 18.7492(14) Å, c= 15.6253(9) Å, = 103.600(4) shows each vanadium site in a distorted octahedral geometry. V1 and V2 have two thf molecules bounded in cis configuration, and V3 completes the hexa-coordination with the diamine teeda. Main bond distances are 2.5149(12) Å for V(1)--Cl(1), 2.062(3) Å for V(1)- ₃-O(3), 2.5554(12) Å for V(1)- ₃-Cl(4), 2.140(3) Å for V(1)–O(1)(thf), 2.243(4) Å for V(3)–N(1)(teeda), and 3.0437(9) for V(1)···V(2).     

Crystal structure of quinoline-2-carboxylic acid ⋅ quinolinium-2-carboxylate

Quinoline-2-carboxylic acid (quinaldic acid), C₁₀H₇NO₂, crystallizes in the monoclinic space group P2₁/c, a =9.724(1) Å, b = 5.937(1) Å, c = 27.545(2) Å, = 90.15(1)°, z = 4, and occurs in the crystal in two tautomeric forms: the neutral molecule and the zwitterion, with molecular ratio 1:1. The compound can be named quinoline-2-carboxylic acid quinolinium-2-carboxylate. The crystal structure is built up of tautomeric pairs consisting of C₉H₆NCOOH and C₉H₆NH⁺COO^– moieties, held up together by hydrogen bonds.     

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)°.     

Crystal structure and spectroscopy of the low-spin iron(II) compound: tris(bipyrimidine)iron(II) bis(triflate), [Fe(bipym)33](CF3SO3)2

The compound [Fe(bipym)₃3](CF₃SO₃)₂ (in which bipym = 2,2-bipyrimidine) crystallizes in the space group P2₁/c, with a = 13.7641(11), b = 18.7557(19), c = 12.3627(11) Å, = 103.085(8)° and Z = 4. The low-spin Fe(II) atom is octahedrally surrounded by six nitrogen atoms of three bipyrimidine groups with Fe—N distances that vary from 1.968(4) to 1.975(4) å. In the far-infrared region the Fe—N vibrations are observed at 359 and 372 cm^-1.