Effects of the Mixing Protocol on the Self-Assembling Process of Water Soluble Porphyrins

The hierarchical self-assembling kinetics of the porphyrin 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (H2TPPS44−) into J-aggregates at high ionic strength under acidic conditions and eventually in the presence of an added chiral templating agent (tartrate) were investigated through UV/Vis spectroscopy, resonance light scattering, and circular dichroism (CD). The effect of changing the mixing order of the various components in the solution on the kinetic parameters and the expression of chirality on the final J-aggregates was evaluated. In this latter case, only when the chiral tartrate anion is premixed with the porphyrin, the resulting nano-architectures exhibit CD spectra that reflect the handedness of the chiral inducer. We discuss a general mechanistic scheme, with the involvement of ion pairs or dimers that offer an alternative pathway to the aggregation process.

Crystal structure of rivastigmine hydrogen tartrate Form I (Exelon®), C14H23N2O2(C4H5O6)

The crystal structure of rivastigmine hydrogen tartrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Rivastigmine hydrogen tartrate crystallizes in space group P21 (#4) with a = 17.538 34(5), b = 8.326 89(2), c = 7.261 11(2) Å, β = 98.7999(2)°, V = 1047.929(4) Å3, and Z = 2. The un-ionized end of the hydrogen tartrate anions forms a very strong hydrogen bond with the ionized end of another anion to form a chain. The ammonium group of the rivastigmine cation forms a strong discrete hydrogen bond with the carbonyl oxygen atom of the un-ionized end of the tartrate anion. These hydrogen bonds form a corrugated network in the bc-plane. Both hydroxyl groups of the tartrate anion form intramolecular O–H⋯O hydrogen bonds. Several C–H⋯O hydrogen bonds appear to contribute to the crystal energy. The powder pattern is included in the Powder Diffraction File™ as entry 00-064-1501.

Crystal structure of lead(II) tartrate: a redetermination

Single crystals of poly[μ4-tartrato-κ6O1,O3:O1′:O2,O4:O4′-lead], [Pb(C4H4O6)]n, were grown in a gel medium. In comparison with the previous structure determination of this compound from laboratory powder X-ray diffraction data [De Ridderet al.(2002).Acta Cryst.C58, m596–m598], the redetermination on the basis of single-crystal data reveals the absolute structure, all atoms with anisotropic displacement parameters and a much higher accuracy in terms of bond lengths and angles. It could be shown that a different space group or incorporation of water as reported for similarly gel-grown lead tartrate crystals is incorrect. In the structure, each Pb2+cation is bonded to eight O atoms of five tartrate anions, while each tartrate anion links four Pb2+cations. The resulting three-dimensional framework is stabilized by O—H...O hydrogen bonds between the OH groups of one tartrate anion and the carboxylate O atoms of adjacent anions.

Crystal structure of 1H,1′H-[2,2′-biimidazol]-3-ium hydrogen tartrate hemihydrate

In the crystal of the title hydrated salt, C6H7N4+·C4H5O6−·0.5H2O, the biimidazole monocation, 1H,1′H-[2,2′-biimidazol]-3-ium, is hydrogen bonded,viaN—H...O, O—H...O and O—H...N hydrogen bonds, to the hydrogen tartrate anion and the water molecule, which is located on a twofold rotation axis, forming sheets parallel to (001). The sheets are linkedviaC—H...O hydrogen bonds, forming a three-dimensional structure. There are also C=O...π interactions present [O...π distances are 3.00 (9) and 3.21 (7) Å], involving the carbonyl O atoms and the imidazolium ring, which may help to consolidate the structure. In the cation, the dihedral angle between the rings is 11.6 (2)°.

Bis(ethylammonium) (–)-(2S,3S)-tartrate monohydrate

The asymmetric unit of the title salt, 2C2H8N+·C4H4O6 −·H2O, contains two ethylammonium cations, one (2S,3S)-(−)-tartrate anion and one water molecule, which are linked by intermolecular N—H...O and O—H...O hydrogen bonds, leading to an infinite three-dimensional framework. An intramolecular hydrogen bond influences the structure of the (2S,3S)-(−)-tartrate anion.

(R)-1-Hydroxybutan-2-ammonium (2R,3R)-tartrate monohydrate

In the formation of the title compound, C4H12NO+·C4H5O6 −·H2O, the (R)-2-amino-1-butanol molecule is converted to a cationic form containing a positively charged amino group, and the tartaric acid molecule to a mono- or half-ionized tartrate anion. The structure is stabilized by a three-dimensional network of hydrogen bonds.

Dicatharanthinium (2R,3R)-tartrate trihydrate

The title salt, bis(methyl 3,4-didehydroibogamin-6-ium-18-carboxylate) (2R,3R)-tartrate trihydrate, 2C21H25N2O2 +·C4H4O6 2−·3H2O, contains two catharanthinium cations, a (2R,3R)-tartrate anion and three water solvent molecules. The cation contains an indole ring system with a planar conformation and a seven-membered nitrogen-containing ring with a distorted chair conformation. A network of O—H...O and N—H...O intermolecular hydrogen bonds stabilizes the crystal packing.

The Solution and Solid State Structure of L-Carnitine L-Tartrate

L-Carnitine forms a salt-like 2:1 adduct with L-tartaric acid which crystallizes in the or-thorhombic space group P212121 with Z = 4 formula units in the unit cell. The lattice is composed of an L-tartrate dianion and two crystallographically independent L-carnitinium cations. The two cations show only very minor differences in their conformation. Anions and cations are arranged in separate stacks which are linked via hydrogen bonds. The tartrate anion and the carnitinium cations show standard geometries known from the structures of other salts of these ions, like the L-carnitine component of the R,L-carnitinium chloride or the dianion in alkali tartrates. The title compound has galenic advantages as an L-carnitine drug because of its non-hygroscopic properties. Aqueous solutions have been shown to contain solvated ionic components, i.e. L-tartrate and L-hydrogentartrate anions, L-tartaric acid (15:70:15) and carnitinium cations. The title compound can therefore be classified as a genuine L-carnitinium salt of L-tartaric acid.