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abstracts
2-carboxy-4-methylaniline is a biologically active molecule serving as a pharmaceutical intermediate [1]. We've synthesized, studied and refined the crystal structure of its derivative 2-carboxy-4-methylanilinium chloride monohydrate using three different electron-density models. In the first model, the ELMAM2 multipolar electron-density database [2] was transferred to the molecule. Theoretical structure factors were also computed from periodic density functional theory calculations [3] and yielded, after multipolar-atoms refinement, the second charge-density model. An alternative electron-density modelling, based on spherical atoms and additional charges on the covalent bonds and electron lone-pair sites, was used in the third model in the refinement versus the theoretical data. The crystallographic refinements, structural properties, electron-density distributions and molecular electrostatic potentials obtained from the different charge-density models were compared.
abstracts
Owing to its multiple sites acting as H-bonds' donors, melamine and its derivatives are considered as excellent building blocks for the construction of various crystalline supramolecular architectures based on phosphate, sulfate, chloride and carboxylic anions [1-10] on one hand and chlorometallate anions on the other hand [11-13]. In our contribution, we will discuss the synthesis, FTIR spectra and the structural investigation using the single crystal X-ray diffraction of (H2Melamine) [CuCl5]Cl, (I). The structural analysis of (I) revealed that it consists of alternating negative and positive layers running through the a-axis direction. The negative layers are built up of alternatively CuCl53- and discrete non-coordination Cl- anions, whereas the positive sheets are formed of [H2melamine2+]2 Hydrogen-bonded dimers. The N-H...N and N-H...Cl interactions are assembled to build three-dimensional H-bond patterns which insure the cohesion within the lattice (Fig. 01). A previous work showed that (I) exhibits antiferromagnetic properties [14]
