Search results for "Diffraction"
showing 10 items of 1584 documents
Two polymorphs of afobazole from powder diffraction data
2012
Afobazole {systematic name: 2-[2-(morpholin-4-yl)ethylsulfanyl]-1H-benzimidazole} is a new anxiolytic drug and Actins, Auzins & Petkune [(2012). Eur. Patent EP10163962] described four polymorphic modifications. In the present study, the crystal structures of two monoclinic polymorphs, 5-ethoxy-2-[2-(morpholin-4-ium-4-yl)ethylsulfanyl]-1H-benzimidazol-3-ium dichloride, C15H23N3O2S2+·2Cl−, (II) and (IV), have been established from laboratory powder diffraction data. The crystal packing and conformation of the dications in (II) and (IV) are different. In (II), there are channels in the [001] direction, which offer atmospheric water molecules an easy way of penetrating into the crystal stru…
Theoretical and Experimental Study of the Crystal Structures, Lattice Vibrations, and Band Structures of Monazite-Type PbCrO4, PbSeO4, SrCrO4, and Sr…
2015
The crystal structures, lattice vibrations, and electronic band structures of PbCrO4, PbSeO4, SrCrO4, and SrSeO4 were studied by ab initio calculations, Raman spectroscopy, X-ray diffraction, and optical-absorption measurements. Calculations properly describe the crystal structures of the four compounds, which are isomorphic to the monazite structure and were confirmed by X-ray diffraction. Information is also obtained on the Raman- and IR-active phonons, with all of the vibrational modes assigned. In addition, the band structures and electronic densities of states of the four compounds were determined. All are indirect-gap semiconductors. In particular, chromates are found to have band gap…
Crystal structure of lactitol (4-O-beta-D-galactopyranosyl-D-glucitol) dihydrate.
1992
Abstract Lactitol dihydrate, C 12 H 24 O 11 ·2H 2 O, is tetragonal, space group P 4 3 2 1 2 with cell dimensions a and b = 8.762(1), c = 45.500(3) A, and V = 3493.2(3) A 3 ; Z = 8, D x = 1.45 Mg.m −3 , λ(Cu- K α ) = 1.54056 A, μ = 1.108 mm −1 , F (000) = 1632, and T = 23°. The structure was solved by direct methods and refined by least-squares calculations to R = 0.054 for 2037 unique observed reflections. There are three intra- and twelve inter-molecular hydrogen bonds in the structure. Bond lengths and angles accord quite well with the mean values of related structures. The galactopyranosyl ring has a chair of conformation.
Insertion of a single-molecule magnet inside a ferromagnetic lattice based on a 3D bimetallic oxalate network: Towards molecular analogues of permane…
2014
The insertion of the single-molecule magnet (SMM) [MnIII(salen) (H2O)]2 2+ (salen2-=N,N-ethylenebis- (salicylideneiminate)) into a ferromagnetic bimetallic oxalate network affords the hybrid compound [MnIII(salen)(H2O)] 2[MnIICrIII(ox)3] 2×(CH3OH)×(CH3CN)2 (1). This cationic Mn2 cluster templates the growth of crystals formed by an unusual achiral 3D oxalate network. The magnetic properties of this hybrid magnet are compared with those of the analogous compounds [Mn III(salen)(H2O)]2[ZnIICr III(ox)3]2×(CH3OH) ×(CH3CN)2 (2) and [InIII(sal 2-trien)][MnIICrIII(ox)3] ×(H2O)0.25×(CH3OH) 0.25×(CH3CN)0.25 (3), which are used as reference compounds. In 2 it has been shown that the magnetic isolatio…
Two copper complexes from two novel naphthalene-sulfonyl-triazole ligands: different nuclearity and different DNA binding and cleavage capabilities.
2013
[EN] Two novel naphthalene-sulfonyl-triazole ligands, 5-amino-N1-(naphthalen-3-ylsulfony1)-1,2,4-triazole (anstrz) and 3,5-diamino-N1-(naphthalen-3-ylsulfony1)-1,2,4-triazole (danstrz), purposely designed to interact with DNA, have been prepared for the first time and then fully characterized by H-1, C-13 NMR and IR spectroscopy, mass spectrometry and elemental analysis. The crystal structures of two copper complexes of these derivatives, i.e. [Cu(anstrz)(4)(NO3)(2)]center dot 4CH(3)OH (1), mononuclear, and [Cu(danstrz)(mu-OAc)(2)](2)center dot 2(danstrz) (OAc = acetato) (2), dinuclear, have been determined by single-crystal X-ray diffraction. In both cases the ligand coordinates in a monod…
Revised structure of trans-resveratrol: Implications for its proposed antioxidant mechanism
2015
The crystal structure of trans-resveratrol has been redetermined by X-ray diffraction. The newly refined structure demonstrates that the previously reported, dynamically disordered hydrogen-bonding network is rather the superposition of two crystallographically independent molecules of trans-resveratrol. This latter arrangement possesses a well-defined hydrogen-bonding network in a unit cell of double the previously reported volume. While not meant as a criticism of the proposed antioxidant mechanism itself, the present studies clearly show that the X-ray diffraction data should no longer be used for its additional support.
Finely Tuned Temperature-Controlled Cargo Release Using Paraffin-Capped Mesoporous Silica Nanoparticles
2011
[EN] Trapped: Mesoporous silica nanoparticles were loaded with a fluorescent guest and functionalized with octadecyltrimethoxysilane. The alkyl chains interact with paraffins, which build a hydrophobic layer around the particle (see picture). Upon melting of the paraffin, the guest molecule is released, as demonstrated in cells for the guest doxorubicin. The release temperature can be tuned by choosing an appropriate paraffin. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Crystal structure of lactitol (4-O-beta-D-galactopyranosyl-D-glucitol).
1992
Abstract Lacitol, C 12 H 24 O 11 , is monoclinic, space group P 2 1 with cell dimensions a = 7.614(1), b = 10.757(1), c = 9.370(1) A, β = 108.19(1)°, and V = 729.0(1) A 3 ; Z = 2, D x = 1.57 Mg.m −3 , λ(Cu- K α ) = 1.5406 A, μ = 1.166 mm −1 , F (000) = 368, and T = 23°. The structure was solved by direct methods and refined by least-squares calculations to R = 0.048 for 1510 unique observed reflections. There are one intra- and eight inter-molecular hydrogen bonds in the structure. Bond lengths and angles accord well with the mean values of related structures. The galactopyranosyl ring has a chair conformation.
Crystallization, spectral, crystallographical, and thermoanalytical studies of succinobucol polymorphism.
2011
Four different polymorphs, A, C, D, and E, of succinobucol were isolated and characterized by means of solid-state nuclear magnetic resonance spectroscopy, single crystal and powder X-ray diffraction, differential scanning calorimetry, thermogravimetry, and attenuated total reflection–infrared spectroscopy. From a number of experiments, the same polymorphs (C, D, and E) and an equilibrium phase mixture B consisting of polymorphs C and D were repeatedly gained using different solvents or their mixtures. Although polymorph A was obtained directly from recrystallization only on few occasions, polymorphs C, D, and E proved to be metastable kinetic polymorphs, which slowly transform to a thermod…
Synthesis and characterization of 4,6-O-butylidene-N-(2-hydroxybenzylidene)-beta-D-glucopyranosylamine: crystal structures of 4,6-O-butylidene-alpha-…
2002
4,6-O-Butylidene-N-(2-hydroxybenzylidene)-β-D-glucopyranosylamine was synthesized and characterized using analytical, spectral and single-crystal X-ray diffraction methods. 1H and 13C NMR studies showed the presence of the β-anomer, which has also been confirmed by the crystal structure. The molecular structure of this compound showed the presence of the tridentate ONO ligation-core. Both precursors, 4,6-O-butylidene-α-D-glucopyranose and 4,6-O-butylidene-β-D-glucopyranosylamine were characterized using single crystal X-ray diffraction. The α-anomeric nature of the former and β-anomeric nature of the latter were proposed based on 1H NMR studies and were confirmed by determining the crystal …