| 1. |
- Besnard, Céline, et al.
(författare)
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Azinyl sulfides - Part LXVIII - X-ray structure of 14-phenyldiquino[3,4 b;4 ',3 '-e][1,4]thiazine
- 2005
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Ingår i: Journal of Chemical Crystallography. - : Springer Science and Business Media LLC. - 1074-1542 .- 1572-8854. ; 35:9, s. 731-736
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Tidskriftsartikel (refereegranskat)abstract
- The title compound 1 (C24H15N3S) crystallizes in an orthorhombic unit cell, with a = 8.2355(3), b = 19.1499(8), and c = 11.3520(5) angstrom, Z = 2, and space group Pnma. The pentacyclic ring system is folded mainly along the S-N(2) axis and slightly along the C(3)-C(4) and C(3')-C(4') axes. The butterfly folding angle between the two quinoline planes is 48.96(3)degrees and the angle between the planes of the two halves of the thiazine ring is 43.46(7)degrees. The central thiazine ring is in a boat conformation. The phenyl substituent is unexpectedly in an axial location with respect to the thiazine ring with the C-N center dot center dot center dot S angle of 114.0(1)degrees and it is perpendicular to the bisecting plane of the pentacyclic ring system.
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| 2. |
- Casari, Barbara M., et al.
(författare)
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The orthorhombic polymorph of diammonium trichromate(VI) decaoxide, α-(NH4)2Cr3O10
- 2007
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Ingår i: Journal of Chemical Crystallography. - : Springer Science and Business Media LLC. - 1074-1542 .- 1572-8854. ; 37:2, s. 135-140
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Tidskriftsartikel (refereegranskat)abstract
- Synthesis and crystal structure of a trichromium(VI) decaoxide compound, α-(NH4)2Cr3O10, is reported. The crystal structure has been determined from three dimensional X-ray data collected at low temperature, 173 K. The structure is isomorphous with its Rb and Cs trichromate analogues, orthorhombic, space group Pbca, with a = 11.2558(3), b = 9.3193(3), c = 18.9819(5) Å and Z = 8. The title compound is composed of discrete [Cr3O10]2- chains held together by the counter ion charge and a hydrogen bonding network. The different conformations adopted by trichromate anion within its ammonium, alkali and organic salts are discussed.
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| 3. |
- Eriksson, Lars, 1960-, et al.
(författare)
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Crystal Structure of Methyl 3-O-α-D-Glucopyranosyl 2-Acetamido-2-Deoxy-α-D-Galactopyranoside Hydrate
- 2023
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Ingår i: Journal of Chemical Crystallography. - : Springer Science and Business Media LLC. - 1074-1542 .- 1572-8854. ; 53:3, s. 400-406
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Tidskriftsartikel (refereegranskat)abstract
- Methyl 3-O-α-D-glucopyranosyl 2-acetamido-2-deoxy-α-D-galactopyranoside as a monohydrate, C15H27NO11·H2O, crystallizes in space group P212121, with four molecules in the unit cell. It constitutes the methyl glycoside of the carbohydrate part of the teichoic acid type polysaccharide from Micrococcus sp. A1, in which the disaccharides are joined through phosphodiester linkages. The conformation of the disaccharide is described by the glycosidic torsion angles ϕ = − 31° and ψ = + 1°, and the hydroxymethyl groups of the constituent monosaccharides are present in the gg and gt conformations for the sugar residues having the gluco- and galacto-configuration, respectively. For the N-acetyl group at C2 of the galactosamine residue the torsion angle τH = 147°, i.e., the amide proton has an antiperiplanar relationship to H2 of the sugar ring. The structure shows extensive hydrogen bonding along the a-direction, including the water molecule, and forms sheets with hydrophilic interactions within the sheets as a result of hydrogen bonding between disaccharides as well as hydrophobic interactions between the sheets, in particular, amongst methyl groups of the N-acetyl group of the α-D-GalpNAc residue in the disaccharides.
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| 4. |
- Henriques, M. S. C., et al.
(författare)
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Columnar Formation in Sodium Triphenylacetate
- 2014
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Ingår i: Journal of Chemical Crystallography. - : Springer Science and Business Media LLC. - 1074-1542 .- 1572-8854. ; 44:11-12, s. 543-547
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Tidskriftsartikel (refereegranskat)abstract
- A new sodium salt, sodium triphenylacetate has been synthesized and characterized by single-crystal X-ray diffraction: triclinic, P-1 with a = 8.3846(2) angstrom, b = 13.5992(3) angstrom, c = 15.5288(3) angstrom, a = 76.7270(11)degrees, b = 74.4500(11)degrees, c = 84.7410(13)degrees, M-W = 656.65, V = 1659.42(6) angstrom(3), Z = 2. The triphenylacetic molecules bridge the metallic ions forming an infinite columnar structure. Calorimetric data does not support the existence of a mesophase induced by temperature.
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| 5. |
- Odell, Luke R., et al.
(författare)
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Crystal and Molecular Structures of Benzyl-(2-chloro-6-methylpyrimidin-4-yl)amine and Benzyl-(4-chloro-6-methylpyrimidin-2-yl)amine : Confirmation of Computationally Predicted Restricted Rotation
- 2007
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Ingår i: Journal of Chemical Crystallography. - : Springer Science and Business Media LLC. - 1074-1542 .- 1572-8854. ; 37:12, s. 817-824
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Tidskriftsartikel (refereegranskat)abstract
- Crystal structures for the isomeric compounds benzyl-(2-chloro-6-methylpyrimidin-4-yl)amine (1), as its hemi-hydrate, and benzyl-(4-chloro-6-methylpyrimidin-2-yl)amine (2) have been determined. Conformational differences lead to multiple molecules, i.e. two and three, in their respective structures. Layers feature in each of the crystal structures and are stabilized by substantial hydrogen-bonding interactions. Compound (1) crystallizes as a hemi-hydrate in the triclinic space group P-1 with a = 8.667(5) Å, b = 11.421(7) Å, c = 12.954(8) Å, α = 78.330(10)°, β = 84.553(10)°, γ = 75.510(9)°, and Z = 4. Compound (2) crystallizes in the monoclinic space group P21/c with a = 10.740(3) Å, b = 21.487(6) Å, c = 14.914(4) Å, β = 95.014(5)°, and Z = 12.
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| 6. |
- Scholtzová, Eva, et al.
(författare)
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Crystal Structure, Infrared Spectra and DFT Study of Benzyl 2,3-Anhydro-β-D-Ribopyranoside
- 2011
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Ingår i: Journal of Chemical Crystallography. - 1074-1542 .- 1572-8854. ; 41:2, s. 167-174
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Tidskriftsartikel (refereegranskat)abstract
- The crystal structure of benzyl 2,3-anhydro-β-D-ribopyranoside is orthorhombic, P212121, Z = 4. The pyranose ring adopts the EO conformation distorted considerably to the 5HO direction. The molecules of the title compound are linked into infinite chains running along the a-axis by bifurcated O–H···O hydrogen bonds. Interaction energies of these hydrogen bonds are significantly different, ~−5.4 for the bond with the smaller and ~−1.1 kcal/mol for the bond with the larger O···O separation. The hydrogen-bond pattern is completed by the two weaker C–H···O intermolecular hydrogen bonds, aiming at the epoxy oxygen atom. IR vibrational spectrum was interpreted by means of comparison with the full list of vibrational modes predicted using DFT method in the solid state. While till 1495 cm−1 the individual bands can be reconciled with single calculated modes, the region below this limit is populated by heavily overlapped HCH, HCO, HOC, COC and HCC bending modes merged with few ν(CC) and ν(CO) modes. The respective “red” shifts of the positions of the ν(OH) bands correlate well with the size of the O···O separation.
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| 7. |
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| 8. |
- Nordén, Bengt, 1945, et al.
(författare)
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Nucleic acid-metal interactions. IV. Complexes of Ag(I) with thymine and cytosine from studies of UV and IR dichroic spectra
- 1986
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Ingår i: Journal of Crystallographic and Spectroscopic Research. - : Springer Science and Business Media LLC. - 0277-8068 .- 1572-8854. ; 16:2, s. 217-226
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Tidskriftsartikel (refereegranskat)abstract
- The linear dichroism of the complexes of thymine and cytosine with silver(I) ions dispersed in stretched polyvinylalcohol films was measured in the infrared and in the near ultraviolet regions of the spectrum. The infrared results were helpful in establishing the orientation of the complexes in the films; they also confirmed that the site of silver binding in the case of cytosine involves the carbonyl oxygen. The ultraviolet spectra were deconvoluted into separate electronic transitions and the corresponding transition moments of silver complexes were determined.
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| 9. |
- Xiong, Ya, et al.
(författare)
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Crystal structures and supramolecular assembly of 1 : 2 piperazine with o- and p-nitrophenol
- 2002
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Ingår i: Journal of Chemical Crystallography. - 1074-1542. ; 32:8, s. 219-225
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Tidskriftsartikel (refereegranskat)abstract
- 1:2 Cocrystals of piperazine (PPN) with o- and p-nitrophenol (oNPH and pNPH) were obtained from aqueous solution. The co-crystal structure of PPN, 2pNPH, and 2H(2)O is triclinic space group P (1) over bar: a = 6.401(1) Angstrom, b = 6.7515(1) Angstrom, c = 11.219(1) Angstrom, alpha = 100.37(1)degrees, beta = 97.10(1)degrees, gamma = 99.99(1)degrees,V= 465.5(1) Angstrom(3), Z = 2. Refinement led to a final conventional R value of 0.0365 for 2081 reflections. PPN, 2oNPH, and 2H(2)O cocrystallize in the monoclinic space group P2(1) : a = 7.753(1) Angstrom, b = 10.888(2) Angstrom, c = 11.378(2) Angstrom, beta = 92.89(1)degrees, V = 953.1(3) Angstrom(3), Z = 2. Refinement led to a final conventional R value of 0.0347 for 1978 reflections. It was found in both cocrystals that the hydroxyl H-atom of pNPH and oNPH was transferred to a N-atom of PPN, forming new ionic complexes PPNH22+.2(oNP(-)) and PPNH22+.2(pNP(-)), respectively.
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