2-[3-(1H-Benzimidazol-2-yl)prop-yl]-1H-benzimidazol-3-ium 3,4,5-tri-hydroxy-benzoate-1,3-bis-(1H-benzimidazol-2-yl)propane-ethyl acetate (2/1/2.94): co-crystallization between a salt, a neutral mol-ecule and a solvent.

The chemical formula of the title compound, 2C17H17N4 +·2C7H5O5 -·C17H16N4·2.94C4H8O2, was established by X-ray diffraction of a single-crystal obtained by reacting 1,3-bis-(benzimidazol-2-yl)propane (L) and gallic acid (HGal) in ethyl acetate. The mol-ecular structure can be described as a salt (HL)+(Gal)- co-crystallized with a mol-ecule L, with a stoichiometric relation of 2:1. Moreover, large voids in the crystal are filled with ethyl acetate, the amount of which was estimated by using a solvent mask during structure refinement, affording the chemical formula (HL +·Gal-)2·L·(C4H8O2)2.94. The arrangement of components in the crystal is driven by O-H⋯O, N-H⋯O and O-H⋯N hydrogen bonds rather than by π-π or C-H⋯π inter-actions. In the crystal, mol-ecules and ions shape the boundary of cylindrical tunnels parallel to [100] via R (rings) and D (discrete) supra-molecular motifs. These voids, which account for about 28% of the unit-cell volume, contain disordered solvent mol-ecules.

Meloxicam hydro-chloride.

The title salt, C14H14N3O4S2 +·Cl- [systematic name: 2-(4-hy-droxy-2-methyl-1,1-dioxo-1,2-benzo-thia-zine-3-amido)-5-methyl-1,3-thia-zol-3-ium chloride] is the hydro-chloride derivative of meloxicam, a drug used to treat pain and inflammation in rheumatic disorders and osteoarthritis. Although its mol-ecular structure is similar to that previously reported for the hydro-bromide analogue, both salts are not isomorphous. Different crystal structures originate from a conformational modification, arising from a degree of rotational freedom for the thia-zolium ring in the cations. By taking as a reference the conformation of meloxicam, the thia-zolium ring is twisted by 10.96 and -16.70° in the hydro-chloride and hydro-bromide salts, while the 1,2-benzo-thia-zine core is a rigid scaffold. This behaviour could explain why meloxicam is a polymorphous compound.

Solution and Solid-State Photophysical Properties of Positional Isomeric Acrylonitrile Derivatives with Core Pyridine and Phenyl Moieties: Experimental and DFT Studies.

The compounds I (Z)-2-(phenyl)-3-(2,4,5-trimethoxyphenyl)acrylonitrile with one side (2,4,5-MeO-), one symmetrical (2Z,2'Z)-2,2'-(1,4-phenylene)bis(3-(2,4,5-trimethoxyphenyl)acrylonitrile), II (both sides with (2,4,5-MeO-), and three positional isomers with pyridine (Z)-2-(pyridin-2- 3, or 4-yl)-3-(2,4,5-trimethoxyphenyl)acrylonitrile, III-V were synthetized and characterized by UV-Vis, fluorescence, IR, H1-NMR, and EI mass spectrometry as well as single crystal X-ray diffraction (SCXRD). The optical properties were strongly influenced by the solvent (hyperchromic and hypochromic shift), which were compared with the solid state. According to the solvatochromism theory, the excited-state (µe) and ground-state (µg) dipole moments were calculated based on the variation of Stokes shift with the solvent's relative permittivity, refractive index, and polarity parameters. SCXRD analyses revealed that the compounds I and II crystallized in the monoclinic system with the space group, P21/n and P21/c, respectively, and with Z = 4 and 2. III, IV, and V crystallized in space groups: orthorhombic, Pbca; triclinic, P-1; and monoclinic, P21 with Z = 1, 2, and 2, respectively. The intermolecular interactions for compounds I-V were investigated using the CCDC Mercury software and their energies were quantified using PIXEL. The density of states (DOS), molecular electrostatic potential surfaces (MEPS), and natural bond orbitals (NBO) of the compounds were determined to evaluate the photophysical properties.

One mol-ecule, three crystal structures: conformational trimorphism of N-[(1S)-1-phenyl-eth-yl]benzamide.

The title compound, C15H15NO, is an enanti-opure small mol-ecule, which has been synthesized many times, although its crystal structure was never determined. By recrystallization from a variety of solvent mixtures (pure aceto-nitrile, ethanol-water, toluene-ethanol, THF-methanol), we obtained three unsolvated polymorphs, in space groups P21 and P212121. Form I is obtained from aceto-nitrile, without admixture of other forms, whereas forms II and III are obtained simultaneously by concomitant crystallizations from alcohol-based solvent mixtures. All forms share the same supra-molecular structure, based on infinite C 1 1(4) chain motifs formed by N-H⋯O inter-molecular hydrogen bonds, as usual for non-sterically hindered amides. However, a conformational modification of the mol-ecular structure, related to the rotation of the phenyl rings, alters the packing of the chains in the crystal structures. The orientation of the chain axis is perpendicular and parallel to the crystallographic twofold screw axis of space group P21 in forms I and II, respectively. As for form III, the asymmetric unit contains two independent mol-ecules forming parallel chains in space group P212121, and the crystal structure combines features of monoclinic forms I and II.

(2SR,3RS)-Methyl 2-(adamantan-1-yl)-3-phenyl-sulfonyl-3-(pyridin-2-ylsulfan-yl)propano-ate dichloro-methane hemisolvate.

The title compound, C(25)H(29)NO(4)S(2) 0.5CH(2)Cl(2), was obtained as a racemate. The pyridine and phenyl rings are arranged face-to-face, giving a weak intra-molecular π-π inter-action [centroid-centroid separation = 3.759 (3) Å]. These inter-actions are extended inter-molecularly, forming chains of stacked rings along [001] with separations of 3.859 (3) and 3.916 (3) Å. The solvent used for crystallization, CH(2)Cl(2), is located in voids between the chains of mol-ecules, with a site occupancy of 0.5.

5-Fluoro-1-[(4S,5R)-5-(2-hydroxy-ethyl)-2,2-dimethyl-1,3-dioxolan-4-yl]pyrimidine-2,4(1H,3H)-dione.

In the title compound, C(11)H(15)FN(2)O(5), the five-membered ring has an envelope conformation, while the six-membered ring is essentially planar, with a maximum deviation of 0.032 (2) Šfrom the mean plane. The crystal packing is stabilized by inter-molecular N-H⋯O and O-H⋯O hydrogen bonds, generating a layer structure parallel to (001).

Molecular modeling of salt (lithium chloride) effects on the enantioselectivity of diethylzinc addition to benzaldehyde in the presence of chiral beta-amino alcohols.

Beta-amino alcohols (S,S,S)-1 and (R,R,S)-1, derived from cyclohexene oxide and containing alpha-phenylethyl auxiliaries, were examined as chiral promoters in the addition of diethylzinc to benzaldehyde. In agreement with literature precedent, the N-alpha-phenylethyl chiral auxiliary had no significant impact on enantioinduction, which is determined by the configuration of the framework's C(OH), with unlike induction. Contrary to some literature reports, stereoinduction by lithium salt derivatives of (S,S,S)-1 and (R,R,S)-1 was lower than that obtained with the free amino alcohol. Remarkable lithium chloride salt effects were observed in the reaction. In particular, an opposite chiral induction was found with (S,S,S)-1-Li(2) as ligand and in the presence of "inert" salt. N-Alkylated derivatives (S,S,S)-3-7 proved to be more efficient ligands, providing higher yields and enantioselectivities in the formation of carbinols (R)- or (S)-2. BP86/DN**//PM3 theoretical calculations proved remarkably successful in reproducing the experimental observations and permitted expansion of Noyori's catalytic cycle [J. Am. Chem. Soc. 1995, 117, 6327] to understand the relevant N-substitution and medium salt effects that determine the enantioselection in this catalytic asymmetric reaction.