X-ray structure of 2,6-dimethoxy-7-methylpurine

The title compound (C₈H₁₀N₄O₂) is monoclinic, with a = 7.740(2), b = 17.044(7), c = 6.992(3) Å, = 100.60(1)°, and space group P2₁/c. Two O-methyl groups are coplanar with the pyrimidine ring. Whereas, the O(6)-methyl group is directed away from the imidazole ring toward the N(1) atom, the O(2)-methyl is pointed away from the N(1) atom toward the N(3) atom. Two intermolecular hydrogen bonds H(8)···N(1) and H(711)···O(2) of 2.48(2) and 2.58(3) Å make a linear arrangement of the molecules. The conformation of the O-methyl groups explains some results of thermal rearrangement of 2,6-dialkoxy-7-methylpurines and differences in alkylations of 2,4-dialkoxypyrimidines and 2,6-dialkoxy-7-methylpurines.     

Influence of the spectator cation on the structure of anionic pyridine-2,6-dicarboxylato complexes of cobalt(II), nickel(II), and copper(II)

The structures of anionic pyridine-2,6-dicarboxylato (pdc^2–) complexes of cobalt, nickel, and copper have been studied. The stoichiometries and structures are very much dependent on whether KOH, Et₄NOH, or NaOH is used in the synthesis to deprotonate the H₂pdc ligand. Crystallographic results are: (1) K₂[Co(pdc)₂] · 7H₂O, orthorhombic, Pnna, Z = 4, a = 20.637(2)Å, b = 13.480(1)Å, c = 8.200(1)Å (2) K₂[Ni(pdc)₂] · 7H₂O, orthorhombic, Pnna, Z = 4, a = 20.648(1)Å, b = 13.375(1)Å, c = 8.2393(8)Å (3) [Co₂(H₂O)₅(pdc)₂] · 2H₂O, monoclinic, P2₁/c, Z = 4, a = 8.3880(6)Å, b = 27.384(2)Å, c = 9.6110(8)Å, = 98.271(6)° (4) [Ni(Hpdc)₂] · 3H₂O, monoclinic, P2₁/c, Z = 4, a = 13.679(1)Å, b = 10.0450(9)Å, c = 13.767(2)Å, = 115.184(7)° (5) Na₆[Co(H₂O)₆][Co(pdc)₂]₄ · 28H₂O, monoclinic, P2₁/n, Z = 2, a = 13.363(1)Å, b = 8.437(1)Å, c = 40.689(3)Å, = 91.288(5)° (6) Na[Ni(Hpdc)(pdc)] · 11.5H₂O, monoclinic, C2/m, Z = 4, a = 15.200(2)Å, b = 22.299(2)Å, c = 8.3596(7)Å, = 118.894(7)° (7) Na[Cu(Hpdc)(pdc)] · 3H₂O, monoclinic, P2₁/n, Z = 4, a = 9.516(4)Å, b = 14.917(6)Å, c = 12.247(5)Å, = 92.00(5)°. The potassium and sodium complexes have extensive K⁺—H₂O and Na⁺—H₂O networks. The fact the Et₄N⁺ ion does not appear in any of the complexes is likely due to the fact that it is incapable of forming the intricate cation—water and hydrogen-bonding networks observed in all of the other structures.     

A structural study of sodium dithionite and its ephemeral dihydrate: A new conformation for the dithionite ion

Raman spectroscopy on solid anhydrous sodium dithionite reveals that it exists in at least two forms in the solid state. MAS²³Na NMR spectra and X-ray powder diffraction patterns of the solids indicate that sodium ions are in different environments in each form of the material. The results suggest that the dithionite anion is conformationally different in each lattice. A single crystal X-ray diffraction study of the recrystallized form of anhydrous sodium dithionite reveals an anion with C₂ geometry and a 16° O-S-S-O torsional angle; nearly eclipsed. (Crystal Data for recrystallized Na₂S₂O₄ area=6.539(1) Å,b=6.552(1) Å,c=6.578(1) Å,V=240.0(1) ų,=121.61(1)°, space group=P2/c,Z=2). Raman spectra of sodium dithionite dihydrate reveal that the dithionite ion is in a different conformation than in either of the anhydrous materials. A single crystal X-ray diffraction study of Na₂S₂O₄·2H₂O reveals a dithionite anion with a substantially shorter S-S bond length than in the anhydrous structure and an O-S-S-O torsional angle of 56°; approximately gauche. (Crystal Data for Na₂S₂O₄·2H₂O area=8.134(1) Å,b=5.756(2) Å,c=14.528(5) Å,V=653.3(3) ų,=106.20(2)°, space group=P2₁/n,Z=4). The structure of the dithionite anion is found to depend critically upon the nature of its external environment.     

The crystal and molecular structure of bis(melamine)silver(I) perchlorate, Ag(C3H6N6)2ClO4

The crystal structure of the title compound, Ag(mela)₂ClO₄ (mela = melamine), has been investigated by X-ray diffraction techniques, the crystals are triclinic, space group P1¯, with a = 5.236(2), b = 7.5385(9) c = 19.063(3) Å, = 99.91(1), = 90.53(2), = 108.32(2)° and Z = 2. The Ag atom has a coordination geometry with two strong bonds (2.162(2) and 2.179(4) Å) to the nitrogen of the melamines and two weak bonds (2.776(4) and 2.785(4) Å) to oxygen atoms of the ClO^– ₄anions. The N—Ag—N vector is markedly nonlinear (angle at Ag 167.7(2)°).     

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.     

Synthesis and crystal structure of indium arsenate and phosphate dihydrates with variscite and metavariscite structure types

The hydrothermal synthesis, crystal structure analysis, and spectroscopic studies of InPO₄·2H₂O (1) and InAsO₄·2H₂O (2) are reported. Compound 1 is isomorphic with metavariscite: monoclinic P2₁/n (No. 14), a = 5.4551(3) Å, b = 10.2293(4) Å, c = 8.8861(3) Å, = 91.489(4)°, Z = 4, and compound 2 is isomorphic with variscite: orthorhombic Pbca (No. 61), a = 10.478(1) Å, b = 9.0998(8) Å, c = 10.345(1) Å, Z = 8. Their three-dimensional frameworks are built of corner sharing InO₄(H₂O)₂ octahedra and MO₄ (M = P⁵⁺ or As⁵⁺) tetrahedra. The water molecules in both compounds have different environments and are involved in different types of hydrogen bonding. Infrared spectroscopy indicates that water molecules are true H₂O species.     

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.     

Identification of a new family of diphosphate compounds, AI2BII3(P2O7)2: Structures of Ag2Co3(P2O7)2, Ag2Mn3(P2O7)2, and Na2Cd3(P2O7)2

Syntheses and single-crystal X-ray structural results are reported for three new mixed diphosphates of the family A^I ₂B^II ₃(P₂O₇)₂; Ag₂Co₃(P₂O₇)₂ (I), Ag₂Mn₃(P₂O₇)₂ (II), and Na₂Cd₃(P₂O₇)₂ (III). All crystallize in the triclinic system, space group P1 bar: (I) a = 5.351(4), b = 6.375(4), c = 16.532(4) Å, = 80.83(6) = 81.45(4), = 72.87(5)°, V = 528.9(6) ų, Z = 2, D _calc = 4.649 mg/m³, R/Rw = 0.0428/0.0548 for 3949 obs. reflns; (II) a = 5.432(7), b = 6.619(6), c = 16.51(3) Å, = 80.78(8) = 82.43(9), = 72.82(7)°, V = 557.7(13) ų, Z = 2, D _calc = 4.338 mg/m³, R/Rw = 0.0679/0.1303 for 2100 obs. reflns and (III) a = 5.67(3), b = 7.08(4), c = 7.90(4) Å, = 77.0(2), = 82.5(2), = 67.8(2)°, V = 286(3) ų, Z = 2, D _calc = 4.249 mg/m³, R/Rw = 0.0307/0.0342 for 1945 obs. reflns. (I) and (II) are isostructural but (III) is of a different type. All three structures are characterized by layers of P₂O₇ groups alternating with layers of mixed metal atoms. Differences are seen in the conglomerate bonding patterns of B atoms and in the irregular geometry of Ag in (I) and (II) compared to the octahedral bonding seen for Na in (III). The differences in structure may be understood in terms of the ratios of the ionic radii of A and B atoms.     

Crystal structure and thermal analysis of 1,5-diammonium-2-methyl pentane sulfate monohydrate

Chemical preparation, x-ray single crystal, and thermal analysis of C₆H₁₈N₂SO₄·H₂O (denoted DMPS) are described. The compound crystallizes in the triclinic system with P space group. Its unit cell dimensions are a = 5.826(1) Å, b = 10.014(1) Å, c = 11.221(1) Å, = 66.716(1)°, = 84.395(1)°, = 83.759(1)°, V = 596.7(1) ų, and Z = 2. The DMPS structure is built up from inorganic chains parallel to the a axis and linked via O(W)-H···O hydrogen bonds. These chains are interconnected by organic groups. Thermal analysis reveals the presence of one water molecule in the structure and shows a reversible weak phase transition.     

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)).     

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.     

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.     

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.     

Synthesis and structure of 4,7,13,16-tetraoxa-1,10-diaza-5,6-benzocyclooctadeca-11,18-dione monohydrate

4,7,13,16-tetraoxa-1,10-diaza-5,6-benzocyclooctadeca-11,18-dione, C₁₆H₂₂N₂O₆·H₂O, (3) was synthesized under thermal conditions, starting from ,-diamine (1) and ,-diester (2). The hydrate of compound (3) was investigated in the solid state by X-ray structural analysis. Crystal data: monoclinic system, space group P2₁/c,a=12.342(4) Å,b=15.978(7) Å,c=8.960(3) Å, =96.72(3)°,Z=4. The structure was solved by direct methods and refined to finalR=0.056,R _w=0.069 for 1962 observed reflections. The structure exhibits internal hydrogen bonds between the etheral O(16) atom and the neighboring amide group. The water molecule connects diamide molecules by one strong hydrogen bond with carbonyl oxygen, and four weak hydrogen bonds with the amide groups and etheral oxygen atoms.     

Synthesis,structure and IR characterization of disodium tetra(9,10-dihydro-9-oxo-10-acridineacetato)zincate(II) bis(ethanol) heptahydrate

The synthesis, crystal structure and IR data are reported for Na₂[Zn(CMA)₄]·2EtOH·7H₂O, where CMA^– is the 9,10-dihydro-9-oxo-10-acridinacetate ion. The complex crystallizes in the monoclinic space group P2/n, with cell dimensionsa=17.335(9),b=8.440(5),c=21.875(12) Å, =91.94(5)°,Z=2. The structure was solved by direct methods and refined to a finalR value of 0.0363 for 3022 non-zero reflections. The Zn²⁺ ion occupies twofold axis and is coordinated to four carboxylate ligands, the ZnO₄ tetrahedron is considerably distorted with Zn–O distances of 1.978(3) and 1.961(3)Å. Each Na⁺ cation interacts with two water, one ethanol, and three carboxylate O atoms comprising distorted octahedron. The Zn²⁺ and Na⁺ cations are linked through monooxygen and syn-syn carboxylate bridges forming a trinuclear, mixed-metal cluster. The Zn...Na separation is 3.267(2)Å and Na...Na distance equals 3.520(2)Å. All oxygen bonded H-atoms are utilized in hydrogen bonds. The acridone rings overlap in the crystal with the 3.5 Å interlayer separations. The compound has been characterized by IR spectroscopy.     

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.     

Synthesis,crystal and molecular structure and vibrational characterization of N,N-dimethyl-oxathioamidate monohydrate

The title compound (SO₂NC₄H₆) has been prepared and characterized by X-ray diffraction and infra-red and Raman spectra. The structure has been refined using single-crystal X-ray diffraction data measured at 295K [MoK-radiation with =0.71073 Å]. The crystals are monoclinic, space groupP2₁/n,Z=4,a=6.240(2),b=6.786(2),c=19.988(1)Å, =108.47(2)°,V=802.8(7)ų.D _calc.=1.566 Mg m^–3,F(000)=392, =8.582 cm^–1. The final agreement factors for 1906 observed refections [I>3(I)] were:R=0.030 andR _w=0.043. The dihedral angle between de C–C–S–N plane and the C–C–O–O plane is 88.31(4). The potassium atom within the title compound structure has a slightly distorted trigonal bipyramidal coordination. Infrared and Raman spectra of the normal CH₃/CD₃ and H₂O/D₂O isotopes and the waterfree compounds at different temperatures made it possible to perform isotopes complete vibrational analysis and clearly shows the very special hydrogen bonded water molecule in the crystal.     

Structure and properties of cobalt(II) complex with a tetraaza macrocycle containing 2-pyridylmethyl pendant arms

The complex [Co(L)]Cl₂·10H²O (1) (L = 2,13,-bis(2-pyridylmethyl)-3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0^1.18,0^7.12]docosane) has been synthesized and structurally characterized. Compound 1 crystallizes in the triclinic system, space group P-1 with a = 9.731(2) Å, b = 9.789(2) Å, c = 11.998(1) Å, = 66.66(1)°, = 76.95(1)°, = 87.99(2)°, V = 1020.4(3) ų, and Z = 1. The crystal structure of 1 shows that the complex is centrosymmetric and the cobalt(II) ion has a slightly distorted octahedral geometry with four nitrogen atoms of the macrocycle and two nitrogen atoms of the pendent arms at the axial positions. Cyclic voltammetry for 1 undergoes reversible one-electron oxidation to the Co(III) and irreversible one-electron reduction to the Co(I).     

Crystal structure of aquo (hydroxo) (ethylenediaminetetraacetato) sodium(I) tin(IV), NaSn(OH)(edta)(H2O)

NaSn(OH)(edta)(H₂O) is monoclinic, space groupP2₁/c, witha=9.747(3)Å,b=9.121(3)Å,c=16.430(6)Å, =98.69(4)°, ų, andZ=4. The coordination environment of Sn(IV) is a capped octahedron. Sn–O distances range from 1.990(6)Å to 2.351(7)Å. Na(I) is five coordinated to three different edta molecules. Na–O distances range from 2.283(9)Å to 2.414(7)Å. The edta ligand presents the E, G/R conformation. The crystal structure is composed of sheets parallel to (001): inside a sheet Sn(OH)(edta) molecules are connected to each other by the Na(I) interactions.     

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.