ESTRADA DE OYA , María Dolores

En el capítulo II, tras una breve referencia a los métodos utilizados el la solución del problema de la fase, clave de todo estudio estructural, se detallan los resultados obtenidos. Las estructuras moleculares y esquemas de emepaquetamiento obtenidos se comparan con los correspondientes a cristales análogos, cuya estructura ha sido determinada...

n the title compound, C 21 H 26 N 2 O 8 , the configurations of the three chiral centres are known from the synthesis, corre- sponding to a d - arabino configuration. Both double bonds show the E configuration in the solid state. Packing of the molecules is governed by normal van der Waals contacts

Lattice-energy calculations in the atom-atom potential approach have been performed for observed and isostructurally derived hypothetical forms of phenothiazine and phenoselenazine compounds. Energy minimizations with respect to cell constants and molecular rigid-body coordinates lead to absolute minima of energy surfaces in all cases. The...

1-(4-Bromophenyl)-3-ethyl-(3,5,6-tri-Oacetyl- 1,2-dideoxy-~t-L-glucofuranoso)[2,1-d]imidazolidine- 2-thione,* C21H25BrN2OTS, M,= 529.40, orthorhombic, P2~2121, a= 12.056 (7), b= 22.420 (9), c =8.841 (2)A, V=2390(2) A3, z=4, Dm= 1.47 (2), D x = 1.47 Mg m -3, 2(Mo Ktx) = 0.7107 A, # = 1.82mm -1, F(000)= 1088, room temperature, final R = 0.070 for...

Lattice-energy minimization for seven glucofuranoimidazolidine crystals was carried out in the atom-atom approach using an (exp-6-1) form for atom-pair interactions. Molecular rotation and translation and also internal rotations were optimized along with cell parameters starting from experimental structures. The fit between optimized and...

1-(4-Bromophenyl)-3-ethyl-(3,5,6,7-tetra-0- acetyl-1,2-dideoxy-n-glycero-P-n-talo-heptofuranoso )- * IUPAC name: 1-{6-acetoxy-3-bromophenyl-2-thioxo-2,3,3a,- 5,6,6a-tetrahydro-1H-furo[2,3-d]imidazol-5-yl }propane-1,2,3-triyl triacetate. 0108-2701/87/061134-05$01.50 [2,1-d]imidazolidine-2-thione, C24H 29BrN 209S, Mr = 601·46,...

M,=433.3, orthorhombic, P2,2~2,, a= 8.466 (2), b .... 27. 136 (5), c - 7.776 (5) A, V = 1786(1)A3, Z=4, D,,,= 1.60(l),Dx= 1.61Mgm -3, Mo Ka, 2 = 0.7107 A, a = 2.42 mm-', F(000) = 888, 300 K, R =0.045 for 1 196 observed independent reflexions. The sugar ring adopts a 4T 3 conformation and the dihedral angle in the bicycle is 72-2(4) ° ....

M r = 433.3, monoclinic, P21, a = 6.924 (3), b=8.661 (1), c=15.039(3)A, #=96.92(3) ° , v= 895.3 (4) A a, Z= 2, D, = 1.598 (5), Dx= 1.607 Mg m -a, Mo Ka, 2 = 0.7107/k, # = 2.42 mm -1, F(000) = 444, T = 300 K, R = 0.039 for 2038 observed independent reflexions. The sugar ring adopts a 4E conformation and the dihedral angle in the bicycle is 49.0...

The PII proteins from the cyanobacteria Synechococcus sp. PCC 7942 and Synechocystis sp. PCC 6803 have been crystallized and high-resolution structures have been obtained using X-ray crystallography. The core of these new structures is similar to that of the PII proteins from Escherichia coli, although the structures of the T- and C-loops...

The solid-state conformation of the title compound, C23H29NOIo, has been unequivocally established. The configuration at C 1 is/3-D-glucopyranose and the pyranose ring is essentially a perfect chair. Only the E rotamer along the N---C bond is observed

DGICYT PB92-0525-C02-02

(5aI-I,6/~-I, 11 aH)-8a-Acetoxy- 1,5-dihydro-2- oxo-lct,10ct-epoxyguaian-6,12-olide, C~7H2206, Mr= 322.3, orthorhombic P2~212~, a= 14.964(6), b= 17.057(4), c=6.218(4)A, V=1587(1)A 3, Z=4, D,n=l.349(5), D x=l.349Mgm -3, 2(MoKa)= 0.7107 A, # = 0.09 mm -l, F(000) = 688, room temperature, final wR--0.068 for 1899 observed reflexions. The...

5-Hydroxy-3,3' ,4',6,7-pentamethoxyflavone (flavone is 2-phenyl-4H-1-benzopyran-4-one ), C20H20- 08, M,= 388·4, monoclinic, P2/n, a= 7·518 (4), b=13·625(3), C=17·766(5)Á, P=98·52(3) 0 , V = 1803 (l)Á\ Z=4, Dx= 1·430Mgm-J, A.(MoKa) = 0·7107 A, !J = 0·104 mm-I, F(OOO) = 816, room temperature, final wR = 0·063 for 1480 ...

The title compound, C 10 H 16 N + H 2 PO 4 H 2 O, crystallizes in the centrosymmetric space group P 2 1 / c with two independent molecules in the asymmetric unit. Therefore, nonlinear optical properties are absent. The crystal packing is governed by hydrogen bonds, so that the phosphate anions are linked head- to-tail, ...