Static Disorder in Hexagonal Crystal Structures of C60 at 100 K and 20 K

C₆₀ · 2C₈H₁₀ (100 K): hexagonal space group P6₃, a = 23.694(4), c = 10.046(2) Å, V = 4884(2) ų, D_x = 1.903 g cm⁻³, Z = 6, F(000) = 2856, γ(CuKa) = 1.54178 Å, μ = 0.84 mm⁻¹. C₆₀ · 2C₈H₁₀ (20 K): hexagonal space group P6₃, a = 23.67(1), c = 10.02(1) Å, V = 4862(6) ų, D_x = 1.912 g cm⁻³, Z = 6, F(000) = 2856, γ(CuKa) = 1.54178 Å, μ = 0.84 mm⁻¹. The structures were determined by Patterson syntheses and rigid-body refinements. The C₆₀ molecules show two orientations with one molecular centre in common. The solvent molecules are disordered too. Static disorder could not be overcome or influenced by cooling down. A coordination number of 10 was found for the fullerene molecules.     

Conversion of 2,4-dihydroxybenzaldehyde to 2-benzoyloxy-4-hydroxybenzaldehyde and structural characterization of both precursor and product

2,4-Dihydroxybenzaldehyde can be acylated at the 2 position if the more reactive 4 position is first protected as the methylmethoxy ether. Deprotection permits isolation of 2-benzoyloxy-4-hydroxybenzaldehyde. 2,4-Dihydroxybenzaldehyde, C₇H₆O₃, crystallizes in P2₁/c, with a = 7.3762(6), b = 11.7455(9), c = 7.3149(6) Å, = 90.533(2)°, Z = 4, and D _X = 1.448 g cm^–3. The individual molecules are characterized by an intramolecular hydrogen bond. The molecules form sheets with additional intermolecular hydrogen bonds. 2-Benzoyloxy-4-hydroxybenzaldehyde, C₁₄H₁₀O₂, crystallizes in Pca2₁, with a = 24.2629(14), b = 3.8445(2), c = 12.3727(8) Å, Z = 4, and D _X = 1.394 g cm^–3. The molecules consist of two planar halves twisted by 51.63(5)° about the ester linkage. Intermolecular hydrogen bonding joins the molecules into ribbons approximately parallel to c.     

Crystal and Molecular Structure of Tosyl Pyrrolidine-2-Methanol (C12H17SO3N)

C₁₂H₁₇SO₃N, M_r = 255.33, Orthorhombic, P2₁2₁2₁, a = 11.703(1) Å, b = 14.797(3) Å, c = 14.971(2) Å, V = 2592.52 ų, Z = 8, D_m = 1.309 Mgm⁻³, D_c = 1.308 Mgm⁻³, mμ = 21.57 cm⁻¹, F(000) = 1088, T = 290 K, final R = 0.080 for 2416 unique reflections. There are two crystallographically independent molecules in the unit cell of the title compound.     

The molecular and crystal structure of 2-oxo-1-pyrrolidine-acetamide

C₆H₁₀N₂O₂, P1 , a = 6,607(2) Å, b = 8,538(2) Å, c = 6,392(2) Å, α = 102,43(2)°, β = 91,11(2)°, y = 79,82(2)°, V = 349,1 ų, Z = 2, D_m = 1,36 g × cm⁻³, D_x = 1,35 g × × cm⁻³, MoKα radiation, λ = 1.71069 Å, μ(MoKα) = 1.11 cm⁻¹. The structure was solved by direct methods. The parameters were refined by full matrix least squares technique to a final R = 0.088 for 834 reflections with ∥F₀∥ > 4σ(F₀). The dihedral angle between the least-squares plane through the pyrrolidine ring and that through the acetamide group is 90.4°. The N H … O hydrogen bonds connect molecules to form bands parallel to the z axis.     

Crystal and molecular structure of 2-diazo-5-phenyl-cyclohexan-1,3-dione

M_r = 214.24, monoclinic space group P 2₁, a = 10.964(2), b = 5.870(2), c = 8.574(2) Å, β = 98.09(2)°, V = 546(1) ų, Z = 2, D_x = 1.302 Mg m⁻³, F(000) = 224, λ (MoKα) = 0.71069 Å, μ = 0.8 mm⁻¹. The crystal structure was determined by direct methods and refined by least-squares procedure to the discrepancy factor R = 0.034. M_r = 214.24, monokline Raumgruppe P 2₁, a = 10.964(2), b = 5.870(2), c = 8.574(2) Å, β = 98.09(2)°, V = 546(1) ų, Z = 2, D_x = 1.302 Mg m⁻³, F(000) = 224, λ(MoKα) = 0.71069 Å, μ = 0.8 mm⁻¹.     

Crystal and Molecular structure of 3,3-Diethyl–2,4,6–[1 H,3 H,5 H] Pyrimidine Trione

C₈H₁₂O₃N₂, M_r = 184.19, Trigonal, R3 (hexagonal axes) a = b = 26.800(1) Å, c = 6.828(3) Å, α = β = 90°, γ = 120°, V = 4247.11 ų, Z = 18, D_m = 1.297 Mg m⁻³, D_c = 1.296 Mg m⁻³, mu = 0.79 mm⁻¹, F(000) = 1764, T = 293 K, final R = 0.080 for 1205 observed reflections. There are two crystallographically independent molecules in the unit cell of the title compound.     

Syntheses and crystal structures of two soybean isoflavone derivatives

Two soybean isoflavone derivatives, 7-methoxy-4′-hydroxyisoflavone (1) and 4′, 7-diethoxyl-5-hydroxyisoflavone (2) were synthesized and their crystal structures were determined by single-crystal X-ray diffraction. Two derivatives crystallize in the monoclinic crystal system, space group P2₁/c. The cell dimensions of 1 are a = 8.696(4) Å, b = 11.947(5) Å, c = 12.078(5) Å, β = 93.594(7)^∘, D_c = 1.423 Mg/m³, V = 1252.3(10) ų, Z = 4, and those of 2 are a = 37.672(12) Å, b = 11.228(4) Å, c = 7.582 (3) Å, β = 94.150(6)^∘, D_c = 1.355 Mg/m³, V = 3198.6(18) ų and Z = 8. They have the same isoflavone skeleton which is composed of a benzopyranone moiety and a phenyl moiety. Hydrogen bonding and π < eqid1 > π stacking interactions assemble 1 into supramolecule with a three-dimensional network. And in the crystal structure of 2, hydrogen bonding and C–H ⋅s π stacking interactions lead to the formation of a two-dimensional network.     

The Crystal and Molecular Structure of 2-(2′-Cyano-2′-amido-ethylenyl)-pyridine

The title compound (C₉H₇N₃O) has been determined from three dimensional X-ray diffraction data. The crystals are monoclinic, a = 4.858(3) Å, b = 15.008(7) Å, c = 11.787(2) Å, ß = 94.107(2)°, V= 857.2(4) ų, z = 4, D_calc = 1.342 g. cm⁻³, space group P2_1/c. The structure was solved by direct methods and refined by full-matrix least-squares method (γ MoK_α′, R = 0.0766).     

Synthesis and characterization of MAgSe4 (M=Rb, Cs)

Syntheses of the title compounds were achieved from supercritical amines. The single crystal X-ray characterization of both MAgSe₄ (M=Rb, Cs) members indicates that they are isostructural. The structure is built from five membered AgSe₄ rings that are stitched together through tetrahedrally coordinated Ag(I) ions to form one dimensional chains running parallel to the a-axis. These chains are separated from each other by the alkali metal cations. Crystal data: orthorhombic, P2₁2₁2₁, Z = 4. RbAgSe₄: a = 5.809(2), b = 8.927(3), c = 13.435(4) Å, U = 698.2(4) ų, and D _c = 4.851 g/cm³. CsAgSe₄: a = 5.855(2), b = 9.090(3), c = 13.885(4) Å, U = 739.0(4) ų, and D _c = 5.003 g/cm³. The anionic chain found in the title compounds has been observed previously, and comparisons among these phases show that the silver ion coordination in the chain varies as a function of cation size. Both the title compounds are valence precise and optical diffuse reflectance studies show that they are semiconductors with moderately large band gaps.     

The Crystal Structure of Hydrated Barium Copper Oxalate

BaCu(C₂O₄₂.6 H₂O is triclinic, P1 , with a = 6.5405(9), b = 9.202(3), c = 10.939(1) Å, α = 85.46(2), β = 79.22(1), γ = 80.45(2), V = 636.99(1) ų, Z = 2, D₀ = 2.14, D_c = 2.465 g. cm⁻³, R = 0.074, wR = 0.0746 for 2219 significant reflections |F₀|≧ 6.0σF₀. The barium has eleven coordinations and the coordination polyhedra is a capped antiprism. Six water oxygen atoms are coordinated whereas the other five are coming from the oxalate group. In the unit cell the molecules form a polymeric network. One lattice water molecule belongs to the coordinating water. The barium oxygen distances vary from 2.75 Å to 3.15 Å.     

The crystal structures of NaAlR4, R=methyl,ethyl, and n-propyl

The crystal structures of the title compounds have been determined from diffractometer data and refined by full-matrix least squares. NaAlMe₄ is orthorhombic,Cmcm,a=9.234(3),b=9.221(3),c=8.303(2) Å,Z=4,D _c=1.03 g cm^–3,R=0.029 for 278 data. NaAlEt₄ is monoclinic,P2₁/c (No. 14),a=13.900(2),b=13.207(2),c=14.443(1) Å,=117.43(1)°,Z=8,D _c=0.94 g cm^–3,R=0.056 for 2747 data. NaAl(n-Pr)₄ is monoclinic,C2/c,a=9.802(5),b=15.336(4),c=21.611(10) A,=98.34(4)°,Z=8,D _c=0.92 g cm^–3,R=0.072 for 899 data. Coordination of Al is essentially tetrahedral in all structures, and closest contacts to Na⁺ involve-carbon atoms of alkyl groups.     

Solid-phase synthesis, crystal structure, and quantum chemical calculation of a molybdenum(II) complex with bis(diethyldithiocarbamate)

The complex Mo(Et₂dtc)₂ [Et₂dtc: bis(diethyldithiocarbamate)] was synthesized by solid-phase reaction at room temperature and characterized by elemental analysis, powder XRD, IR, ¹H NMR and TG/DTA. Its crystal structure was determined by X-ray single crystal diffraction. The crystals are monoclinic with space group P2₁/c, a=0.61800(12) nm; b=1.1540(2) nm; c=1.1610(2) nm; β=95.78(3)°; V=0.8238(3) nm³; D _c=1.582 g/cm³; Z=2 F(000)=400; μ=1.285 mm⁻¹; R=0.0703; wR=0.2330; GOF=1.060. The coordination geometry of Mo atom, by four S anions from Et₂dtc ligand, is that of a slightly distorted planar square. Furthermore, the optimized geometry, charge distribution, and thermodynamic functions were calculated by quantum chemical method.     

The emission and structure of a new laser crystal Nd3+: NaY(WO4)2

A new laser Nd³⁺ : NaY(WO₄)₂ crystal rod of Φ 2.5 × 5 mm was pumped by a xenon flash lamp, and a 1.06 μm laser output was for the first time obtained in our laboratory, which has a threshold lower than 1 J. The crystal structure of NaY(WO₄)₂ was determined. The crystal is tetragonal, with the space group 14₁/a, a = 5.205(2) Å, c = 11.251(3) Å, V = 304.8(2) ų, Z = 2, D_calc = 6.62 g/cm³, D_obs = 6.51 g/cm³.     

Asymmetric hetero-Diels-Alder reactions: X-ray structures of three novel chiral dihydropyrimidines

Three novel dihydropyrimidine compounds N8,6-di(4-nitrophenyl)-(3R)-ethyl-(7R)-methyl-5-oxo-2,3,6,7-tetrahydrooxazolo[3,2,c] pyrimidine-8-carboxamide (2), N8,6-di((4-methylphenyl)-sulfonyl)-(3R)-ethyl-5-oxo-(7R)-phenyl-2,3,6,7-tetrahydrooxazolo [3,2,c]pyrimidine-8-carboxamide (3) and N8,6-di ((4-methylphenyl)sulfonyl)-(3R)-ethyl-(7R)-methyl-5-oxo-2,3,6,7-tetrahydrooxazolo[3,2,c] pyrimidine-8-carboxamide (4) have been prepared (from 2-amino-1-butanol of 64.4% e.e.) and structurally characterized by X-ray crystallography. All three compounds contain stereogenic centers, but the crystal of (2) chosen was found to be racemic whilst those of (3) and (4) were found to be homochiral. Compound (2) crystallizes in the monoclinic space group P2₁/c, with a = 17.958(4), b = 12.431(2), c = 9.653(2) Å, = 96.20(3)°, U = 2142.3(7) ų, Z = 4, and D _c = 1.449 g cm^–3. Compounds (3) and (4) both crystallize in the monoclinic space group P2₁, with a = 9.349(2), b = 5.824(5), c = 26.513(8) Å, = 99.43(2)°, U = 1424.1(13) ų, Z = 2 and D _c = 1.389 g cm^–3 for (3), and a = 5.9526(9), b = 16.3521(10), c = 13.2263(11) Å, = 92.81(12)°, U = 1285.9(2) ų, Z = 2 and D _c = 1.378 g cm^–3 for (4).     

Crystal structure determination of 2-acetylamino-4-benzoyl-5,5-dimethyl-4,5-dihydro-1,3,4-thiadiazolin,C13H15N3O2S

Thiosemicarbazone is receiving increasing interest because of the biological activity of some of its derivatives. Mr = 277.35, space group P2₁2₁2₁, Z = 4, a = 9.290(3), b = = 11.512(2), c = 13.286(2) Å, V = 1421 (1) ų, D_m = 1.29(1) Mg m⁻³, D_x = 1.296 Mg m⁻³, λ(MoK_α) = 0.71062 Å, μ = 0.230 mm⁻¹, F(000) = 584, T = 296 K, final R = 0.028 for 1255 reflections. All hydrogen atoms were located. The structure determed by X-ray analysis confirms the chemical results. The structure analysis of the title compound is described and its molecular and crystal structure discussed.     

Electrical Characterization of Irradiation plus Annealing – induced VAsZnGa Pairs in p-type GaAs (Zn) Crystals

Effect of fast electron irradiation (E =2.2 Mev, ϕ_c = 1 × 10¹⁶ el/cm²) and subsequent annealings (T = 150 to 350 °C, t = 10 to 600 min) of zinc-doped p-type GaAs crystals on the formation and dissociation of V_AsZn_Ga, pairs is studied. An analysis of the formation and dissociation kinetics of V_AsZn_Ga pairs permitted to find the diffusion coefficient of radiation-induced arsenic vacancies D(D = 1.5 × 10⁻¹⁸, 1 × 10⁻¹⁷ and 5 × 10⁻¹⁷ cm²/s at 150, 175 and 200 °C accordingly), their migration energy ϵ_m(ϵ_m = 1.1 eV), the binding energy of V_AsZn_Ga, pairs ϵ_b(ϵ_b = 0.5 eV), and also their dissociation energy ϵ_d(ϵ_d = 1.6 eV).     

Crystal and molecular structures of N-alkyl-N,N-dimethyl-3-(heptamethyltrisiloxan-3-yl) propylammonium bromides

C₁₆H₄₂NO₂Si₃Br: M_r = 444.76, monoclinic space group P 2₁/c, a = 23.300(8), b = 8.918(4), c = 13.403(2) Å, β = 101.69(4)°, V = 2727(1) ų, D_x = 1.08 Mgm⁻³, D_exp = 1.06 Mgm⁻³, Z = 4, F(000) = 932, λ(MoKα) = 0.71069 Å, μ = 16.3 cm⁻¹. The crystal structure was determined by direct methods and refined by least-squares procedure to the discrepancy factor R = 0.117. C₁₅H₄₀NO₂ Si₃Br: M_r = 430.34, monoclinic space group P2₁/c, a = 23.460(4), b = 8.518(2), c = 13.403(2) Å, β = 102.03(2)°, V = 2619(1) ų, D_x = 1.09 Mgm⁻³, D_exp = 1.07 Mg⁻³, Z = 4, F (000) = 920, λ(MoKα) = 0.71069 Å, μ = 33.9 cm⁻¹. The crystal structure was determined by least-squares refinement of the structure model derived from structure determination of C₁₆H₄₂NO₂·Si₃Br to the discrepancy factor R = 0.099. C₁₆H₄₂NO₂Si₃Br: Daten siehe oben. C₁₅H₄₀NO₂Si₃Br: Daten siehe oben.     

2-(1-Methyl-1H-indol-3-ylmethylene)-1-aza-bicyclo[2.2.2] octan-3-one: Acid-catalyzed isomerization of the Z isomer to the E isomer

Crystals of (Z)-2-(1-methyl-1H-indol-3-ylmethylene)-1-aza-bicyclo[2.2.2]octan-3-one (I) were obtained from a condensation reaction of 1-methyl-1H-indole-3-carboxaldehyde with 1-aza-bicyclo[2.2.2]octan-3-one and subsequent crystallization of the product from methanol. The isomeric (E)-2-(1-methyl-1H-indol-3-ylmethylene)-1-aza-bicyclo[2.2.2] octan-3-one hydrochloride (II) was obtained by treating a methanolic solution of I with a 1M solution of hydrogen chloride diethyl ether, followed by crystallization of resultant product from methanol. Crystal data: I, is monoclinic, P2₁, a = 5.7440(10), b = 11.102(2), c = 10.708(2) Å, = 91.751(10)°, and V = 682.5(2) ų with Z = 2, for D _cal= 1.296 mg/m³ and II, is monoclinic, P2₁/c, a = 8.8510(2), b = 17.4990(5), c = 20.4300(5) Å, = 101.3620(12)°, V = 3102.26(14) with Z = 8, for D _cal= 1.316 mg/m³.     

Crystal and molecular structure of 1-diazo-2,3,4,5-tetraphenylcyclopentadiene

M_r = 396.30, monoclinic space group P 2₁/c, a = 10.145(2), b = 18.523(4), c = 12.443(2) Å, β = 110.31(2)°, V = 2193(1) ų, Z = 4, D_x = 1.201 Mg m⁻³, F(000) = 832, λ(MoKα) = 0.71069 Å, μ = 0.7 mm⁻¹. The crystal structure was determined by direct methods and refined by least-squares procedure to the discrepancy factor R = 0.039.     

Primary to secondary sphere coordination of 18-crown-6 to lanthanide (III) nitrates: Structural analysis of [Pr(NO3)3-(18-crown-6)] and [M(NO3)3(OH2)3]·18-crown-6 (M=Y,Eu, Tb−Lu)

The direct reaction of hydrated lanthanide nitrate salts with 18-crown-6 in 31 CH₃CNCH₃OH has resulted in the isolation and structural characterization of [Pr(NO₃)₃(18-crown-6)] and [M(NO₃)₃(OH₂)₃]·18-crown-6 (M=Y, Eu, Tb–Lu). (The Eu and Yb analogs were confirmed with preliminary cell data only.) [Pr(NO₃)₃(18-crown-6)] is 12-coordinate icosahedral and crystallizes in the orthorhombic space group Pbca with (at 20°C)a=12.230(2),b=15.598(4),c=21.777(9)Å andD _calc=1.89 g cm^–3 forZ=8. The seven isostructural [Pr(NO₃)₃(18-crown-6)] complexes all contain 9-coordinate capped square antiprismatic metal centers hydrogen bonded via the bound water molecules to D_3d 18-crown-6 within the lattice to form hydrogen bonded polymeric chains. Each complex is orthorhombic Pnma with cell parameters as follows: M=Tb (20°C):a=15.242(6),b=14.253(11),c=11.070(6)Å,D _calc=1.83 g cm^–3 forZ=4; M=Dy (20°C):a=15.248(3),b=14.239(5),c=11.058(3)Å,D _calc=1.84 g cm^–3 forZ=4; M=Y (19°C):a=15.260(2),b=14.238(2),c=11.048(3) Å,D _calc=1.64 g cm^–3 for Z=4; M=Ho (20°C):a=15.226(4),b=14.208(15),c=11.028(3)Å,D _calc=1.86 g cm^–3 forZ=4; M=Er (20°C):a=15.250(3),b=14.208(7),c=11.028(3)Å,D _calc=1.87 g cm^–3 forZ=4; M=Tm (20°C):a=15.246(6),b=14.190(16),c=11.013(6) Å,D _calc=1.88 g cm^–3 forZ=4; M=Lu (21°C):a=15.244(9),b=14.158(6),c=10.980(7)Å,D _calc=1.90 g cm^–3 forZ=4.