Hydrogen bonding in melamine compounds of amino acids

The theme of this work is part of the study of intermolecular interactions that hold the crystal structures of hybrid compounds based sulphuric acid, nitric acid, Melamine, Diethylamine, L-(+) - glutamic acid, DL-2-amino butyric acid. The aim of this work is to enlarge our laboratory researches [1-3] and methods in synthesis of new hybrid compounds consisting in organic cation(s) and mineral anion(s). We have obtained single crystals of a few samples after several trials and we plan to synthesize and characterize these crystals by X-ray diffraction, FTIR and Raman. The crystals structures allow us to study the 3D network hydrogen bonding, electron density and collect several other informations useful in FTIR and Raman studies of these hybrid compounds.

Structure and thermal analysis of amino acids

The twenty amino acids are chemical compounds having two functional groups (carboxyl:-COOH, amine:-NH2) and an asymmetric carbon (except glycine). They are amphoteric and can exist as zwitterion. Because of the reactivity of amino acids (esterification, amidation, N-alkylisation, N-arylation, protonation), and their conformation (aliphatic, aromatic) chemical, properties (acid, base, and / or hydroxylated, solubility), and physical properties (absorbance, NLO), our laboratory contribute to the study (synthesis and X ray single crystal structures) of new organic-inorganic hybrid compounds which allows to the development of materials with novel properties [1-3]. Our work is also based on the relationship between the thermal decomposition of amino acids and their chemical structures, dozens compounds were selected and the results of the DTA, TG and DTG thermal decomposition was performed by several methods. Diffraction results are used for the identification of degradation mechanisms of the chemical structure, the stability of the compound studied and the anticipation of possible syntheses of hybrid compounds.

Synthesis, spectroscopic and structural analysis of a melamine copper complex

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]