Cadmium sulfite hexahydrate revisited

The present structural revision of the title compound, tetra­cadmium tetra­sulfite hexa­hydrate, [Cd4(SO3)4(H2O)5]·H2O, is a low-temperature upgrade (T = 100 K and R = 0.017) of the original room-temperature structure reported by Kiers & Vos [Cryst. Struct. Commun. (1978). 7, 399–403; T = 293 K and R = 0.080). The compound is a three-dimensional polymer with four independent cadmium centres, four sulfite anions and six water mol­ecules, five of them coordinated to two cadmium centres and the remaining one an unbound solvent mol­ecule which completes the asymmetric unit. There are two types of cadmium environment: CdO8 (through four chelating sulfite ligands) and CdO6 (by way of six monocoordinated ligands). The former groups form planar arrays [parallel to (001) and separated by half a unit cell translation along c], made up of chains running along [110] and [10], respectively. These chains are, in turn, inter­connected both in an intra­planar as well as in an inter­planar fashion by the latter CdO6 polyhedra into a tight three-dimensional framework. There is, in addition, an extensive network of hydrogen bonds, in which all 12 water H atoms act as donors and eight O atoms from all four sulfite groups and two water mol­ecules act as acceptors

Hydrogen-bonding synthons in lamotrigine salts: 3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazin-2-ium 2-[(2-carboxyphenyl)disulfanyl]benzoate in its monohydrate and anhydrous forms

Lamotrigine is a drug used in the treatment of epilepsy and related convulsive diseases. The drug in its free form is rather inadequate for pharmacological use due to poor absorption by the patient, which limits its bioavailability. On the other hand, the lamotrigine mol­ecule is an excellent hydrogen-bonding agent and this has been exploited intensively in the search for better formulations. The formulation presently commercialized (under the brand name Lamictal) is rather complex and includes a number of anions in addition to the active pharmaceutical ingredient (API). The title salts of lamotrigine, namely 3,5-di­amino-6-(2,3-di­chloro­phen­yl)-1,2,4-triazin-2-ium 2-[(2-carb­oxy­phen­yl)di­sul­fan­yl]benzoate monohydrate, C9H8Cl2N5+·C14H9O4S2-·H2O, (I), and the anhydrate, C9H8Cl2N5+·C14H9O4S2-, (II), contain a lamotriginium cation (L), a hydrogen di­thio­dibenzoate monoanion (D) and, in the case of (I), a disordered solvent water mol­ecule. Both L and D present their usual configurations severely twisted around their central C-C and S-S bonds, respectively. The supra­molecular structure generated by the many available donor and acceptor sites is characterized by a planar anti­symmetric motif of the form D-L-L-D, i.e. the structural building block. Although this characteristic motif is extremely similar in both structures, its conformation involves different donors and acceptors in its R22(8) central L-L homosynthon. The lateral R22(8) D-L hetero­synthons are, on the other hand, identical. These substructures are further connected by strong hydrogen bonds into broad two-dimensional structures, in turn weakly linked to each other. Even if the homo- and heterosynthons in (I) and (II) are rather frequent in lamotrigine structural chemistry, the composite tetra­meric synthon appears to be much less common. The occurrence of these motifs among lamotrigine salts and cocrystals is analyzed.Fil: Freire Espeleta, Eleonora. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Polla, Griselda Ines. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Baggio, Ricardo Fortunato. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentin

Poly[[tetra-μ3-acetato-hexa-μ2-acetato-diaqua- μ2-oxalato-tetra-praseodymium(III)] dihydrate]

The title complex, {[Pr4(C2H3O 2)10(C2O4)(H2O)2] ·2H2O} n , was synthesized under hydro-thermal conditions from praseodymium acetate and the ionic liquid 1-butyl-3-methyl-imidazolium chloride via an in situ oxalate-ligand synthesis. The compound is a two-dimensional polymer and in the structure presents tightly bound planes parallel to (100), which are in turn linked into a three-dimensional network by hydrogen bonds involving both coordinated and solvent water mol-ecules. The oxalate anion lies across an inversion centre and acts as a bridge between pairs of Pr atoms within a tetra-nuclear segment of the polymer.Fil: Gutkowski, Karin. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Freire Espeleta, Eleonora. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Baggio, Ricardo. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentin

A triclinic polymorph of cyclo-tetra - Thio-saccharinato- 8 S:S-tetra-kis[(triphenyl-phosphane-P)silver(I)]

The triclinic structure of the title compound, cyclo-tetra-kis-(-1,1-dioxo- 1 6,2-benzothia-zole-3-thiol-ato- 2 S:S)tetra-kis- [(triphenyl-phosphane-P)silver(I)], [Ag4(C7H4NO2S2)4(C18H15P)4], is a polymorph of the previously reported monoclinic structure [Dennehy, Mandolesi, Quinzani & Jennings (2007). Z. Anorg. Allg. Chem. 633, 2746-2752]. In both polymorphs, the complex lies on a crystallographic inversion centre and the bond distances are closely comparable. Some differences can be found in the inter-atomic angles and torsion angles involving the inner Ag4S4 skeleton. The polymorphs contain essentially identical two-dimensional layers, but with different layer stacking arrangements. In the triclinic form, all layers are related by lattice translation, while in the monoclinic form they are arranged around glide planes so that adjacent layers are mirrored with respect to each other.Fil: Dennehy, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Sur; ArgentinaFil: Freire Espeleta, Eleonora. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Unidad de Actividad de Materiales (CAC); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Baggio, Ricardo Fortunato. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Unidad de Actividad de Materiales (CAC); Argentin

Di-μ-acetato-κ3 O,O′:O;κ3 O:O,O′-bis­[(acetato-κ2 O,O′)(1,10-phenan­throline-κ2 N,N′)cadmium(II)]

The title compound, [Cd2(C2H3O2)4(C12H8N2)2], consists of dimeric units built up around a crystallographic symmetry centre. Each cadmium(II) unit is chelated by a 1,10-phenanthroline (phen) group and two acetate ligands, one of which also acts as a bridge, linking both seven-coordinated cadmium(II) centres. The crystal structure is governed by a single π–π inter­action between stacked phen groups [centroid–centroid distance 3.5209 (11) Å], leading to a planar structure parallel to (010)

Polymorphic forms of bendamustine hydro­chloride: crystal structure, thermal properties and stability at ambient conditions

Crystallographic, thermal and stability analyses are presented of three different anhydrated forms of bendamustine hydro­chloride [(I), (III) and (IV)] and a fourth, monohydrated one (II). Since form (I) presents the higher melting point and the higher heat of fusion, according to the 'heat of fusion' rule it should be the most stable in thermodynamic terms [Burger & Ramberger (1979). Mikrochim. Acta, 72, 259-271], though it is unstable in high-humidity conditions. The monohydrate structure (II), in turn, dehydrates by heating and topotactically transform into anhydrate (III). This latter form appears as less stable than anhydrate (I), to which it is linked via a monotropic relationship. For these three different forms, the crystal structure has been determined by single crystal X-ray diffraction. The crystal structures and molecular conformations of forms (II) and (III) are quite similar, as expected from the topotactic transformation linking them; furthermore, under high-humidity conditions, form (III) shows changes compatible with a transformation into form (II) within 24 h. The crystal structure of form (I) is different from the other two. The remaining polymorphic form (IV) could only be obtained as a powder, from which its crystalline structure could not be determined. The relative thermodynamic stability of the different crystalline forms was determined by differential scanning calorimetry and thermogravimetrical studies, and their stability under different humidity conditions analysed.Fil: Gaztañaga, Pablo Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Baggio, Ricardo Fortunato. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Vega, Daniel Roberto. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentin

Aripiprazole salts: II. Aripiprazole perchlorate

The molecular structure of aripiprazole perchlorate (systematic name: 4-(2,3-dichlorophenyl)-1-{4-[(2-oxo-1,2,3,4-tetrahydroquinolin-7-yl)oxy]butyl} piperazin-1-ium perchlorate), C23H28Cl2N 3O2 +-ClO4-, does not differ substantially from the recently published structure of aripiprazole nitrate [Freire, Polla & Baggio (2012). Acta Cryst. C68, o170-o173]. Both compounds have almost identical bond distances, bond angles and torsion angles. The two different counter-ions occupy equivalent places in the two structures, giving rise to very similar first-order 'packing motifs'. However, these elemental arrangements interact with each other in different ways in the two structures, leading to two-dimensional arrays with quite different organizations.Fil: Freire Espeleta, Eleonora. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Constituyentes); Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Polla, Griselda Ines. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Constituyentes); ArgentinaFil: Baggio, Ricardo Fortunato. Comisión Nacional de Energía Atómica. Gerencia del Área de Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Constituyentes); Argentin

Aripiprazole salts: I. Aripiprazole nitrate

The crystal structure of aripiprazole nitrate (systematic name: 4-(2,3-dichloro-phen-yl)-1-{4-[(2-oxo-1,2,3,4-tetra-hydro-quino-lin-7-yl)-oxy] but-yl}piperazin-1-ium nitrate), C 23H 28Cl 2N 3O 2 +·NO 3 - or AripH +·NO 3 -, is presented and the mol-ecule com-pared with the aripiprazole molecules reported so far in the literature. Bond distances and angles appear very similar, except for a slight lengthening of the C - NH distances involving the protonated N atom, and the main differences are to be found in the mol-ecular spatial arrangement (revealed by the sequence of torsion angles) and the inter-molecular inter-actions (resulting from structural elements specific to this structure, viz. the nitrate counter-ions on one hand and the extra protons on the other hand as hydrogen-bond acceptors and donors, respectively). The result is the formation of [100] strips, laterally linked by weak π-π and C - Cl⋯π inter-actions, leading to a family of undulating sheets parallel to (010).Fil: Freire Espeleta, Eleonora. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Polla, Griselda Ines. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Baggio, Ricardo Fortunato. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentin

A new polymorph of bis[2,6-bis(1H-benzimidazol-2-yl-κN 3)pyridinido-κN]zinc(II)

The title compound, [Zn(C19H12N5)2], crystallizes in the tetragonal space group P43212, with the monomer residing on a twofold axis. The imidazole N-bound H atoms are disordered over the two positions, with refined occupancies of 0.59 (3) and 0.41 (3). The strong similarities to, and slight differences from, a reported P42212 polymorph which has a 50% smaller unit-cell volume [Harvey, Baggio, Muñoz & Baggio (2003). Acta Cryst. C59, m283-m285], to which the present structure bears a group-subgroup relationship, are discussed.Fil: Harvey, Miguel Angel. Consejo Nacional de Invest.cientif.y Tecnicas. Centro Nacional Patagonico; Argentina. Universidad Nacional del Comahue; ArgentinaFil: Suarez, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Doctorovich, Fabio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Baggio, Ricardo Fortunato. Comisión Nacional de Energía Atómica; Argentin

Cyclization of 1,2:3,4-di-O-isopropylidene-α-D-galacto-1,6-hexodialdo-1,5-pyranose acylhydrazone and semicarbazone

Cyclization of 1,2:3,4-di-O-isopropylidene-α-D-galacto-1,6-hexodialdo-1,5-pyranose benzoylhydrazone using acetylating mixtures led us to the corresponding (2R)- and (2S)-5- phenyl-1,3,4-oxadiazoline derivatives. The same conditions applied to the semicarbazone produced the 5-methyl-1,3,4-oxadiazoline derivative as the main compound, which is formed with acetylating mixtures even at room temperature. X-Ray analysis and NMR techniques were used to determine the stereochemistry of the new asymmetric centers.Fil: Martins Alho, Miriam Amelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; Argentina; Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Química; Argentina;Fil: Baggio, Ricardo Fortunato. Comisión Nacional de Energía Atómica. Gerencia de Investigación y Aplicaciones; Argentina;Fil: D'accorso, Norma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; Argentina