X-ray studies of crystalline complexes involving amino acids and peptides. XLIV. Invariant features of supramolecular association and chiral effects in the complexes of arginine and lysine with tartaric acid

Crystal structure and Hirshfeld surface analysis of poly[[di-μ3-glycine-lithium] perchlorate]

In the title salt, {[Li(C2H5NO2)2]ClO4} n , the Li+ cation is coordinated by four carboxyl-ate oxygen atoms of the glycine mol-ecules with a distorted tetra-hedral geometry. The glycine exists in a zwitterionic form with protonated amino and deprotonated carboxyl-ate groups. In the crystalline state, the title salt is primarily stabilized by inter-molecular N-H⋯O and Cα-H⋯O inter-actions which inter-connect various units. Hirshfeld surface analysis indicates that the inter-molecular H⋯O/O⋯H inter-actions are the most important contributors to the crystal packing.

Crystal structure and Hirshfeld surface analysis of 1-carb-oxy-2-(3,4-di-hydroxy-phen-yl)ethan-1-aminium bromide 2-ammonio-3-(3,4-di-hydroxy-phen-yl)propano-ate

In the title mol-ecular salt, C9H12NO4+·Br-·C9H11NO4, one of the dopa mol-ecules is in the cationic form in which the α-amino group is protonated and the α-carb-oxy-lic acid group is uncharged, while the second dopa mol-ecule is in the zwitterion form. The Br- anion occupies a special position and is located on a twofold rotation axis. The two dopa mol-ecules are inter-connected by short O-H⋯O hydrogen bonds. In the crystal, the various units are linked by O-H⋯O, N-H⋯Br and N-H⋯O hydrogen bonds, forming a three-dimensional framework. The title compound was refined as an inversion twin with an absolute structure parameter of 0.023 (8).

Crystal structure and Hirshfeld surface analysis of 1-carb-oxy-2-(3,4-di-hydroxy-phen-yl)ethan-1-aminium chloride 2-ammonio-3-(3,4-di-hydroxy-phen-yl)propano-ate: a new polymorph of l-dopa HCl and isotypic with its bromide counterpart

The title mol-ecular salt, C9H12NO4+·Cl-·C9H11NO4, is isotypic with that of the bromide counterpart [Kathiravan et al. (2016 ▸). Acta Cryst. E72, 1544-1548]. The title salt is a second monoclinic polymorph of the l-dopa HCl structure reported earlier in the monoclinic space group P21 [Jandacek & Earle (1971 ▸). Acta Cryst. B27, 841-845; Mostad & Rømming (1974 ▸). Acta Chemica Scand. B28, 1161-1168]. In the title compound, monoclinic space group I2, one of the dopa mol-ecules has a positive charge with a protonated α-amino group and the α-carb-oxy-lic acid group uncharged, while the second dopa mol-ecule has a neutral charge, the α-amino group is protonated and the α-carb-oxy-lic acid is deprotonated. In the previously reported form, a single dopa mol-ecule is observed in which the α-amino group is protonated and the α-carb-oxy-lic acid group is uncharged. The invariant and variations of various types of inter-molecular inter-actions present in these two forms of dopa HCl structures are discussed with the aid of two-dimensional fingerprint plots.

Crystal structure of poly[[μ2-di-aqua-di-aqua-μ2-l-proline-κ(2) O:O'-strontium] dibromide]

In the title coordination polymer, {[Sr(C5H9NO2)(H2O)4]Br2} n , the proline mol-ecule exists in a zwitterionic form with one of the ring C atoms disordered over two sites [site-occupancy factors = 0.57 (6):0.43 (6)]. The Sr(II) ion is nine-coordinated by six water O atoms, two monodentate and two μ2-bridging, and three carboxyl-ate O atoms of the proline ligands, with two bridging [Sr-O range = 2.524 (4)-2.800 (5) Å]. In the crystal, there is no direct inter-action between the proline mol-ecules. However, the proline and water mol-ecules associate with the bromide counter-anions through a number of inter-molecular O-H⋯Br and N-H⋯Br hydrogen-bonding inter-actions, giving a three-dimensional supra-molecular structure.

Crystal structure of catena-poly[[[tri-aqua-strontium]-di-μ2-glycinato] dibromide]

In the title coordination polymer, {[Sr(C2H5NO2)2(H2O)3]Br2} n , the Sr(2+) ion and one of the water mol-ecules are located on twofold rotation axes. The alkaline earth ion is nine-coordinated by three water O atoms and six O atoms of the carboxyl-ate groups of four glycine ligands, two in a chelating mode and two in a monodentate mode. The glycine mol-ecule exists in a zwitterionic form and bridges the cations into chains parallel to [001]. The Br(-) counter-anions are located between the chains. Inter-molecular hydrogen bonds are formed between the amino and carboxyl-ate groups of neighbouring glycine ligands, generating a head-to-tail sequence. Adjacent head-to-tail sequences are further inter-connected by inter-molecular N-H⋯Br hydrogen-bonding inter-actions into sheets parallel to (100). O-H⋯Br and O-H⋯O hydrogen bonds involving the coordinating water mol-ecules are also present, consolidating the three-dimensional hydrogen-bonding network.

catena-Poly[[[aqua-(glycine-κO)lithium]-μ-glycine-κ(2) O:O'] bromide]

In the title coordination polymer, {[Li(C₂H₅NO₂)₂(H₂O)]Br}_n, the Li⁺ cation is coordinated by three carboxyl­ate O atoms of zwitterionic glycine mol­ecules and by a water mol­ecule, forming a distorted tetra­hedral geometry. One of the two glycine mol­ecules bridges neighbouring complexes, forming an infinite chain parallel to the c axis. Polymeric chains are further linked by extensive hydrogen bonds involving the Br⁻ anions and glycine and water mol­ecules, producing a three-dimensional network.

Glycine-phthalic acid (1/1)

In the title compound, C₂H₅NO₂·C₈H₆O₄, the glycine mol­ecule exists as a zwitterion (2-aza­niumyl­ethano­ate) with a positively charged amino group and a negatively charged carboxyl­ate group. In the crystal, N—H⋯O and O—H⋯O hydrogen bonds link the components into layers parallel to the ab plane. The central part of each layer is composed of hydrogen-bonded glycine zwitterions, while phthalic acid mol­ecules inter­act with the zwitterions in such a way that benzene rings protrude up and down from the layer.

Dolabranes from the Chinese Mangrove, Ceriops tagal

Six new dolabranes, named tagalsins P-U (1-6), were isolated from stems and twigs of a Chinese mangrove, Ceriops tagal, along with seven known dolabranes, an abietane, and a pimarane. The structures of these compounds were established on the basis of spectroscopic data or comparison with data in the literature. The relative configurations of tagalsins P and Q (1, 2), two new 15,16-dinor-dolabranes, were confirmed by means of single-crystal X-ray diffraction analysis. This is the first report of 16-nordolabranes and 15,16-dinordolabranes from plants of the Ceriops genus. Tagalsins Q (2), R (3), and U (6) showed moderate antifeedant activity against the third-instar larvae of Brontispa longissima at a concentration of 1 mg/mL. However, none of the new dolabranes exhibited significant activity against human cancer cell lines.