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Nicolás Yutronic Juan Merchán Paul Jara Guillermo Gonzalez María T. Garland 《Journal of inclusion phenomena and macrocyclic chemistry》2003,45(1-2):51-57
Thiourea reacts with 1-azabicyclo[2.2.2]octane (quinuclidine, Q) in methanol at room temperature leading to the formation of Q(3-thiourea).Single crystal X-ray diffraction analysis shows that the product has a rhombohedral structure, = = 90°, = 120°,a = b = 15.9371(2),c = 12.4248(2),which may bedescribed as a thiourea matrix defining hexagonal channels where the quinuclidine molecules are located. The 13C-cross polarisation magic angle spinning (CP-MAS) study indicates that the guest inside the cavities has high conformational, rotational and translational mobility at room temperature. Thermal studies indicate that the structural identity of the thiourea matrix remains after a partial loss of amine, and this result suggests that the thiourea-amine inclusion compound possesses an open host structure, or that a topotactic process is associated. 相似文献
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In a previous paper, we have shown the utility of cluster analysis for identifying patterns in the way the C atoms of fragments of the -turn are distributed in three dimensions. This work has been extended to the C–C bond vectors of 2- and 3-side-chain fragments. Again, distinct patterns emerge and 10 and 12 classes of vector orientation have been identified for the 2- and 3-vector problem, respectively. These clusters of vector distribution provide an optimal reduced set of design criteria for the de novo generation of novel peptidomimetics for fragments of the -turn. 相似文献
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Sergio Baggio M. Enriqueta Díaz de Vivar María Teresa Garland Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(4):m157-m158
The title compound, {[Zn2(SO3)2(C10H8N2)]·H2O}n, is a two‐dimensional polymer built up of a [ZnSO3]n chain evolving around a 21 axis and interconnected by a 4,4′‐bipyridine spacer. The resulting two‐dimensional structures are linked, in turn, by hydrogen bonding mediated by the solvent water molecule. The organic ligand lies on a centre of symmetry located on the mid‐point of the bond between the rings, while the solvent water molecule is halved by a twofold axis passing through the O atom. 相似文献
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Ana María Atria María Teresa Garland Ricardo Baggio Piedad Corts 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(7):m297-m302
Two new oxo complexes, namely hexa‐μ2‐acetato‐acetatoaquabis(di‐3‐pyridylamine)di‐μ3‐oxo‐tetrairon(III) chloride monohydrate ethanol 1.25‐solvate, [Fe4(C2H3O2)7O2(C10H9N3)2(H2O)]Cl·1.25C2H6O·H2O, (I), containing a tetranuclear [Fe4(μ3‐O)2]8+ unit, and 2‐methylimidazolium hexa‐μ2‐acetato‐acetatodiaqua‐μ3‐oxo‐triiron(III) chloride dihydrate, (C4H7N2)[Fe3(C2H3O2)7O(H2O)2]Cl·2H2O, (II), with a trinuclear [Fe3(μ3‐O)]7+ unit, are presented. Both structures are formed by two well differentiated entities, viz. a compact isolated cluster composed of FeIII ions coordinated to O2− and CH3CO2− anions, and an external group formed by a central Cl− ion surrounded by different solvent groups to which the anion is bound through hydrogen bonding. In the case of (I), charge balance cannot be achieved within the groups, so the structure is macroscopically ionic; in the case of (II), in contrast, each group is locally neutral owing to the internal compensation of charges. The trinuclear complex crystallizes with the metal cluster, chloride anion and 2‐methylimidazolium cation bisected by a crystallographic mirror plane. 相似文献
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