Juan Saulo González-González

Supramolecular architectures of conformationally controlled 1,3-phenyl-dioxalamic molecular clefts through hydrogen bonding and steric restraints

In this contribution the supramolecular architecture of a series of six 1,3-phenyl-dioxalamic molecular clefts is described. The conformation was controlled by the use of Me and OMe group substitution in the phenyl spacer. The structural and conformational study was carried out by X-ray diffraction analysis, DFT calculations at PBEPBE 6-31+G (3df, 3pd) theory level and variable temperature 1H NMR in solution. The C2-Me group exerts a dual influence on the conformation adopting the endo(sc) or exo(ac) conformations in the oxalamic arms, meanwhile the C2-OMe group leads to the adoption of the exo(ap) conformation. DFT study results showed that the exo(ap)–exo(ap) conformation is more stable than the other conformations due to the conjugation that stabilizes the molecule and minimizes the conformational energy. Supramolecular arrays in oxalamate/oxalamide derivatives of 1,3-diaminobenzene, 2-methyl-benzene-1,3-diamine and 2,4,6-trimethyl-benzene-1,3-diamine are directed by self-complementary N–H⋯O hydrogen bonding interactions, whose organization in the crystal depends on the twist of the oxalamic arms, meanwhile in oxalamate/oxalamide derivatives of 5-tert-butyl-2,6-diamineanisol with an exo(ap)–exo(ap) conformation, the supramolecular arrays are directed by π-stacking, dipolar carbonyl–carbonyl interactions and C–H⋯O soft contacts. N1,N1′-(1,3-(2,4,6-Trimethyl)-phenyl)-bis-(N2-(2-(2-hydroxyethoxy)ethyl)oxalamide) adopts the form of a supramolecular meso-helix, which is the first example of helical 1,3-phenyl-dioxalamide.

Synthesis, Molecular Structure of Diethyl Phenylenebis(Methylene)Dicarbamates and FTIR Spectroscopy Molecular Recognition Study with Benzenediols

The synthesis, density functional theory (DFT) molecular structure and Fourier transform infrared spectroscopy (FTIR) molecular recognition study of diethyl phenylenebis(methylene) dicarbamates with 1,2- and 1,3-benzenediols is described. The formation of the complexes was confirmed by the shift of the O-H stretching bands in the IR spectra of the complexes compared with the IR spectra of the noncomplexed benzenediols.

Helical supramolecular assembly of N2,N2′-bis[3-(morpholin-4-yl)propyl]-N1,N1′-(1,2-phenylene)dioxalamide dimethyl sulfoxide monosolvate

In the title compound, C(24)H(36)N(6)O(6)·C(2)H(6)OS, the carbonyl groups are in an antiperiplanar conformation, with O=C-C=O torsion angles of 178.59 (15) and -172.08 (16)°. An intramolecular hydrogen-bonding pattern is depicted by four N-H...O interactions, which form two adjacent S(5)S(5) motifs, and an N-H...N interaction, which forms an S(6) ring motif. Intermolecular N-H...O hydrogen bonding and C-H...O soft interactions allow the formation of a meso-helix. The title compound is the first example of a helical 1,2-phenylenedioxalamide. The oxalamide traps one molecule of dimethyl sulfoxide through N-H...O hydrogen bonding. C-H...O soft interactions give rise to the two-dimensional structure.

N,N'-Bis(4-amino-benz-yl)oxalamide.

In the title compound, C16H18N4O2, the two carbonyl groups are in an antiperiplanar conformation with an O=C—C=O torsion angle of 173.86 (17)°. In the crystal, a pair of intermolecular N—H⋯O hydrogen bonds, forming an R 2 2(10) ring motif, connect the molecules into an inversion dimer. The dimers are further linked by N—H⋯N and C—H⋯π interactions, forming a zigzag chain along the b axis.

Hydrated Solid Forms of Theophylline and Caffeine Obtained by Mechanochemistry

Caffeine and theophylline are methyl-xantine drugs, which are affected by water leading to their hydrated forms. The purpose of this work was to prepare and characterize hydrated forms of caffeine and theophylline by mechanochemistry. The obtained products were characterized by infrared spectroscopy and Xray powder diffraction. The infrared spectra and diffractograms of the ground products were similar to the reported for caffeine and theophylline hydrates.