Crystal Structure of 14-Deoxy-11,12-Didehydroandrographolide — A Diterpenoid

The crystal structure of 14-deoxy-11,12-didehydroandrographolide has been determined by X-ray structure analysis. The compound crystallizes in the trigonal space group P3₁ with cell parameters a = b 15.860(3), c = 6.437(2) Å. The structure has been solved by direct methods and refined to R = 0.048. The six-membered rings are trans-fused and both are in the chair conformation. The furan ring is planar with maximum deviation −0.011 (4) Å for C(14). Molecular are held together by hydrogen bonds.     

Refined Crystal and Molecular Structure of Andrographolide — Diterpene

A refined crystal structure of andrographolide has been obtained by X-ray anaysis using CuKα radiation. It crystallizes in the monoclinic crystal system with unique b-axis in space group P2₁. The unit cell parameters are a = 6.552(2) Å, b = 8.009(1) Å, c = 17.989(1) Å and interaxial angle β = 97.32(1)°. The structure has been solved by direct methods and was refined up to R = 0.041, ωR = 0.0464. Both the cyclohexane rings are in chair conformation with the furan ring in twist conformation. The crystal structure is stabilized by hydrogen bonding.     

Crystal and Molecular Structure of Diterpenoid Alkaloid 3-Acetylaconitine

Abstract  3-Acetylaconitine (1), C₃₆H₄₉NO₁₂, was isolated from the ammonium hydroxide wetted root of A. szechenyianum Gay. X-ray diffraction analysis demonstrated that it consists of four-six-membered rings A, B, C, D and two-five-membered rings E, F. The fused-ring system A, B, C and D are in chair, chair, chair and boat conformations, respectively; ring E is in a half-chair; and ring F is in an envelope confirmation. The crystal of 3-acetylaconitine is in orthorhombic crystal system with space group P2₁2₁2₁, lattice constants: a = 9.2002(8) ?, b = 11.06454(9) ?, and c = 33.072(3) ?, V = 3543.3(5) ?³, Z = 4. Index Abstract  3-Acetylaconitine, C₃₆H₄₉NO₁₂, was isolated from the ammonium hydroxide wetted root of A. szechenyianum Gay, and its crystal and molecular structure was determined by X-ray diffraction analysis.      

The Crystal and Molecular Structure of 11,12‐dibromo‐ 7,8—benzo‐1,5‐di(p—tolylsulphonyl)‐1,5‐diazacyclononan

The crystal structure of the title compound, C₂₅H₂₆Br₂N₂O₄S₂ was determined by single crystal X‐ray diffraction technique. The crystals are monoclinic, space group C 2/c, with a=20.7142(2) Å b=11.7910(2) Å, c= 10.6735(3) Å, β=98.549(2)°, V=2577.94(9) ų, Z=4. The structure was solved by direct methods and refined by least‐squares methods to a final R=0.046 for 1866 observed reflections with I>2sigma(I). The title compound, displays disordered geometry around the C1 atom located almost on twofold axis. The nine‐membered heterocylic ring is close to the half‐chair conformation. The dihedral angle between phenyl rings is 34.2(1)°.     

Novel Indole-Pyrazine Alkaloid: Synthesis,Characterization, and Crystal Structure

Crystallography Reports - A heterocyclic molecule of a novel class with a multiple ring system has been synthesized using a new and simple strategy and acetic acid as catalyst. The structure of the...     

Crystal Structure of 5,6‐Dinitrobenzimidazole.monohydrate

The title compound (C₇H₆N₄O₅) crystallizes in the monoclinic space group P2₁/c with a=8.566(1) Å, b=14.493(3) Å, c=7.583(1) Å, β=87.75(1)°, V=940.7(3) ų, Z=4, D_x=1.597 g.cm^‐3. The structure was solved by direct methods and refined by full‐matrix least‐squares method (R=0.0696). The title compound consists of an imidazole ring with the two NO₂ groups and one water molecule. The short inter‐ molecular N‐H^…N [2.03(5) Å] and O_water‐H^…O [1.98(5) Å] hydrogen bonds are highly effective in holding the molecule in a stable state as a whole.     

The Molecular and Crystal Structure of 3β-O-(2′,3′ -O-isoropylidene-α-L-rhamnopyranosyl) — digitoxigenin

3β-O-(2′,3′ -O-isoropylidene-α-L-rhamnopyranosyl) — digitoxigenin crystallizes in the monoclinic space group P 2₁ with two molecules C₃₂H₄₈O₈ per unit cell and the lattice constants a = 7.865, b = 6.470, c = 29.803 Å, β = 93.95°. The structure was solved by direct methods of phases determination and subsequently refined by least squares technique to the final R-value 0.06. The position of the lactone ring is disordered in the crystal.     

Crystal Structure of 2‐methyl cinnamanilide and 2‐methoxy cinnamanilide

The crystal structures of two cinnamanilide derivatives 2‐methyl cinnamanilide (C₁₆ H₁₅ N O – compound I) and 2‐methoxy cinnamanilide (C₁₆ H₁₅ N O₂ – compound II) are reported. In both crystal structures, the cinnamamide group is almost planar. The inter‐planar angle between the two phenyl rings are 71.6(1)° for compound I and 7.5(1)° for compound II. The N‐H…O and C‐H…O type of hydrogen bond interactions between the amide group and the carbonyl group stabilizes the molecular packing as chains in the crystal lattice.     

Growth Characteristics of Mercuric Iodide Single Crystal

The HgI₂ single crystal with few large smooth faces, high quality and 360 g in weight has been grown by a new technique of modified vapour phase located point method, and the growth characteristics of HgI₂ single crystals have been investigated in detail. It is found by means of X-ray diffraction that the crystals grown with the c-axis parallel or perpendicular to the pedestal plane have both the prism faces {110}.     

Epitaxial Growth of α-Mercuric Iodide

Mercuric iodide has been grown for the first time heteroepitaxially on a substrate. α-HgI₂ is deposited as a single crystalline layer which is azimuthally completely oriented. The orientation of the grown layer has been confirmed with texture X-ray diffractometry, reflection powder diffractometry and Atomic Force Microscopy.     

超快闪烁晶体碘化亚铜的生长研究

在氮气保护的条件下,采用恒温蒸发法,在乙腈溶液中生长超快闪烁晶体碘化亚铜,获得了尺寸为3 mm×2 mm×2 mm的单晶体.测定了CuI在乙腈中的溶解度曲线和结晶度曲线.利用紫外-可见光谱对CuI的乙腈溶液中的碘离子存在形式作了判断和分析,对溶液中的黑色沉淀物氧化铜进行了IR和XRD表征.通过结晶实验,研究了温度、氧气和还原剂对晶体结晶形态的影响.实验表明:晶体生长温度应在45 ℃以上,铜粉具有很好的还原性能.     

The Crystal and Molecular Structure of tert‐Butoxycarbonyl ‐ α‐aminoisobutyryl ‐ isoleucyl ‐methylester

The crystal structure of the synthetic peptide Boc — Aib — Ile ‐ OMe (C₁₆ H₃ 0 N₂ O₅ ) has been determined from three‐dimensional X — ray diffraction data. The peptide crystallizes in triclinic space group P1 with a = 9.570(9), b = 10.261(7), c = 10.610(2) Å , α = 101.9(0), β = 91.7(0), γ = 98.6(0)° V = 1006.1(12) ų, Z = 2, D_calc = 1.09 Mg m^‐3. The structure was solved by direct methods and refined by full‐matrix least‐squares method to an R value of 0.072 (λ = 1.5418Å). The conformation of Aib residue in molecule A is αL and in molecule B is αR. The Ile residue in molecule A adopts folded conformation, while in molecule B it is in the extended region. The peptide units are trans and show significant deviations from planarity.     

Crystal Structure of Rabdoternin A

Abstract  

Rabdoternin A is a natural diterpenoid isolated from Rabdosia rubescen and its crystal structure was determined by X-ray single crystal diffraction. The compound compactly packs in an orthorhombic unit cell in the P2₁2₁2₁ space group with unit cell dimensions a = 7.9200(10) ?, b = 11.2411(14) ?, c = 20.474(2) ?, V = 1822.8(4) ?³ and Z = 4. Two intermolecular hydrogen bonds assemble the title compound into infinite two-dimensional networks along (001) plane.     

Crystal structure of a daturalactone – A withanolide

The crystal structure of a daturalactone derivative has been determined by X-ray structural analysis. The compound crystallizes in orthorhomic space group P2₁2₁2₁ with cell parameters a - 15.141(1) Å, b - 18.425(1) Å, c - 19.251(2) Å. The structure was solved by direct methods and refined to R - 0.082. The asymmetric unit contains two non-equivalent molecules. Extensive hydrogen bonding is present. The conformations of the rings are A: a distorted half-chair, B: a perfect half-chair, C: a chair, D: an envelope-half chair and E: a twist boat. Ring junctions A/B, B/C, C/D are all trans fused. Methyl carbons C(18), C(19), C(27) and the lactone moiety is β-oriented whereas the methyl carbons C(21) and C(28) are α-oriented.     

Static fatigue in glass — A reappraisal

The delayed failure of soda-lime glass was tested after different surface and heat treatments and at different humidities. It was found that the treatment history of the glass strongly influenced the characteristics times of failure and the effect of humidity on these times. However, the functional dependence of log failure time on relative stress was similar for most treatments. Analysis of the distributions of failure times at particular stresses showed that the log failure time was not linear with applied stress, as often assumed. The experimental data fit better inverse proportionality between log time and relative stress. Analysis of previous data on crack propagation (‘K - ν curves’) in glass also showed this proportionality. Some theoretical reasons for these results are examined.