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]

Synthesis and Chiral Recognition Properties of a Novel Colorimetric Chiral Sensor for Carboxylic Anions

Chiral colorimetric sensor 4 has been synthesized, and the structure characterized by IR and 1H NMR spectroscopy, mass spectrometry, and elemental analysis. The chiral recognition of the receptor was studied by 1H NMR and UV-vis spectroscopy. The results of non-linear curve fitting indicate that the receptor 4 and l- or d-mandelate and alanine anions form a 1:1 stoichiometric complex. The obvious colour change of receptor 4 can be observed by the naked eye when the enantiomers of mandelate and alanine anions are added, which demonstrates that receptor 4 may be used as the colorimetric sensor for the two carboxylic anions.

Sulfate/oxalate exchange by lobster hepatopancreatic basolateral membrane vesicles

Purified basolateral membrane vesicles (BLMV) were prepared from lobster hepatopancreas by osmotic disruption and discontinuous sucrose gradient centrifugation. Radiolabeled sulfate uptake was stimulated by 10 mM intravesicular oxalate compared with gluconate-loaded vesicles. Sulfate/oxalate exchange was not affected by transmembrane valinomycin-induced potassium diffusion potentials (inside negative or inside positive), suggesting electroneutral anion transport. Sulfate uptake was not stimulated by the similar carboxylic anions formate, succinate, oxaloacetate, or ketoglutarate. Sulfate influx occurred by at least one saturable Michaelis-Menten carrier system [apparent Km = 6.0 +/- 1.7 mM; maximum flux (Jmax) = 382.3 +/- 37.0 pmol.mg protein-1 x 7 s-1]. Sulfate/oxalate exchange was significantly reduced by the anion antiport inhibitors 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid and 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid but was not affected by bumetanide or furosemide. The possible physiological role of this exchange mechanism in anion/sulfate transport across the crustacean hepatopancreas is discussed.