Independent Part Of Unit Cell Research Articles

Crystal Structure of 2,2-dimethyl-5-[(2-metylhydrazinyl)methylidene-1,3-dioxan-4,6-dione

The 2,2-dimethyl-5-[(2-metylhydrazinyl)methylidene-1,3-dioxan-4,6-dione has been prepared and its crystal structure of 2,2-dimethyl-5-[(2-metylhydrazinyl)methylidene-1,3-dioxan-4,6-dione (C8H12O4, Mr = 200.19) has been determinated by single-crystal X-ray diffraction analysis. The compound crystallizes in the monoclinic system with space group C2/c and unit cell parameters: a = 27.9436(6), b = 10.1683(3), c = 14.1604(3) A, β = 100.334(2)° and Z = 16. The final reliability index is 0.0412 for the 2866 observed reflections. The two molecules of 1 are localized in independent part of unit cell. The title compounds are linked through N–H⋯O, C–H⋯O and C–H⋯N hydrogen bonds into 1-D rail-like supramolecular chains. The 2,2-dimethyl-5-[(2-metylhydrazinyl)methylidene-1,3-dioxan-4,6-dione has been prepared and its crystal structure of 2,2-dimethyl-5-[(2-metylhydrazinyl)methylidene-1,3-dioxan-4,6- has been determinated by single-crystal X-ray diffraction analysis. .

Crystal Structure of 2-Cyclohexylethyl α-d-Mannopyranoside

The crystal structure of 2-cyclohexylethyl α-d-mannopyranoside (C14H26O6, Mr = 290.35) has been determined by single crystal X-ray diffraction analysis. The compound crystallizes in the monoclinic crystal system with space group C2 and unit cell parameters: a = 14.2420(2), b = 6.0320(1), c = 17.8065(3) A, β = 102.131(2)° and Z = 4. The final reliability index is 0.0256 for 2,654 observed reflections. The one molecule of 2-cyclohexylethyl α-d-mannopyranoside is localized in independent part of unit cell. The molecules of 2-cyclohexylethyl α-d-mannopyranoside are linked through O–H···O hydrogen bond into bilayer.

The Molecular and Crystal Structures of 2-Iodokojic Acid: Experimental and Theoretical Determination

The crystal structure of 2-iodokojic acid, (2-jodo-3-hydroxy-6-hydroxymethyl)-4-H-pyran-4-one) (C6H5IO4, Mr = 268.00) has been determined by single crystal X-ray diffraction analysis. The compound crystallizes in the orthorhombic crystal system with space group Pc21b and unit cell parameters: a = 4.0830(2), b = 15.3510(5), c = 23.517(1) A and Z = 8. The final reliability index is 0.0288 for 2,584 observed reflections. The two molecules of iodokojic acid, slightly differing in their molecular structure, are localized in independent part of unit cell. The crystal packing is stabilized by O–H···O hydrogen bonds and I···O intermolecular interactions. The molecular structure of iodokojic acid determined experimentally little differs from that obtained by the applied theoretical (Hartree–Fock and four versions of DFT) methods, the differences should not be taken as a measure of the reliability of the theoretical methods. The crystal structure of 2-iodokojic acid, (2-jodo-3-hydroxy-6-hydroxymethyl)-4-H-pyran-4-one) (C6H5IO4, Mr = 268.00) has been determined by single crystal X-ray diffraction analysis. The two molecules of iodokojic acid, slightly differing in their molecular structure, are localized in independent part of unit cell. The crystal packing is stabilized by O–H···O hydrogen bonds and I···O intermolecular interactions. The molecular structure of iodokojic acid determined experimentally little differs from obtained by the applied theoretical (Hartree–Fock and four versions of DFT) methods, the differences should not be taken as a measure of the reliability of the theoretical methods.

Crystal Structure of 2-(2,2-Dibromovinyl)-1-methyl-1H-imidazole-4,5-dicarbonitrile

The crystal structure of 2-(2,2-dibromovinyl)-1-methyl-1H-imidazole-4,5-dicarbonitrile (C8H4Br2N4, Mr = 315.92) has been determined by single crystal X-ray diffraction analysis. The compound crystallizes in the monoclinic crystal system with space group P21/c and unit cell parameters: a = 15.144(2), b = 16.382(3), c = 8.267(1) A, β = 95.76(2)o and Z = 8. The final reliability index is 0.0297 for 2505 observed reflections. The two molecules of 2-(2,2-dibromovinyl)-4,5-dicyano-1-methylimidazole are localized in independent part of unit cell. The crystal packing is stabilized by C–H···N hydrogen bonds and Br···N intermolecular interactions.

Crystal structure and solid-state 13C NMR analysis of N- p-nitrophenyl-α- d-ribopyranosylamine, N- p-nitrophenyl-α- d-xylopyranosylamine, and solid-state 13C NMR analysis of N- p-nitrophenyl-2,3,4-tri- O-acetyl-β- d-lyxopyranosylamine and N- p-nitrophenyl-2,3,4-tri- O-acetyl-α- l-arabinopyranosylamine

The X-ray diffraction analysis of N- p-nitrophenyl-α- d-ribopyranosylamine ( 1) and N- p-nitrophenyl-α- d-xylopyranosylamine ( 2) was performed. It was found that an independent part of the unit cell of compound 1 is formed by three molecules of sugar whereas the crystals of compound 2 have one molecule in the independent part of the crystal unit cell. Additionally, 1 crystallizes with one molecule of water. The solvent molecule forms an extensive hydrogen bond network with the hydroxyl groups of the sugar, and this efficiently stabilizes the crystal lattice. Contrary to 2, the sugar moieties of 1 adopt the 1 C 4 conformation. In the spectra of 2, N- p-nitrophenyl-2,3,4-tri- O-acetyl-β- d-lyxopyranosylamine and N- p-nitrophenyl-2,3,4-tri- O-acetyl-α- l-arabinopyranosylamine the number of resonances does not exceed the number of carbon atoms in the molecules, thus indicating no polymorphism. In the spectrum of ( 1) the signals are split, confirming the presence of three independent molecules in the crystal unit cell.