Azidoacetone as a complexing agent of transition metals Ni2+/Co2+ promoted dissociation of the C-C bond in azidoacetone

The relevance of metal interactions with azides has led us to the study of the complexation of some transition metals, nickel and cobalt, by azidoacetone by means of electrospray ionization mass spectrometry (ESI-MS). Complexes were obtained from solutions of NiCl(2) and CoCl(2) , in methanol/water. Nickel was electrosprayed with other counter ion, bromide (Br), as well as other solvent (ethanol/water). For nickel and cobalt, the complexes detected were single positively charged, with various stoichiometries, some resulted from the fragmentation of the ligand, the loss of N(2) being quite common. The most abundant species were [Ni(II)Az(2)X](+) where X = Cl, Br and Az = azidoacetone. Some of the complexes showed solvation with the solvent components. Metal reduction was observed in complexes where a radical was lost, resulting from the homolytic cleavage of a metal coordination bond. Collision-induced dissociation (CID) experiments followed by tandem mass spectrometry (MS-MS) analysis were not absolutely conclusive about the coordination site. However, terminal ions of the fragmentation routes were explained by a gas-phase mechanism proposed where a C-C bond was activated and the metal inserted subsequently. Density functional theory calculations provided structures for some complexes. In [Ni(II)Az(2)X](+) species, one azidoacetone ligand is monodentate and the dominant binding location is the alkylated nitrogen and not the carbonyl group. The other azidoacetone ligand is bidentate showing coordination through alkylated nitrogen and the carbonyl group. These are also the preferential binding sites for the most stable isomer of [Ni(II)AzX](+) species.     

Study of the structural and electronic properties of valproic acid and new derivatives used as anticonvulsant agents

The conformational and electronic characteristics of the polar O(9)═C(8)-X(10) moiety in the anticonvulsant valproic acid (Vpa) drug and some of their amides and ester derivatives are analyzed at the B3LYP level using the 6-31+G(d,p) and 6-311++G(d,p) 6d,10f basis sets. Exploring the delocalization of the electron density of the O(9)═C(8)-X(10) moiety by means of ELF, NBO, and AIM calculations, we found that the bending away from coplanarity of the atoms in O(9)═C(8)-X(10) is accompanied by a three-dimensional arrangement of donor and acceptor proton units closing nearly planar pseudorings of four, five, and six members arising from stabilizing interactions around the O(9)═C(8)-X(10) backbone. From the structure-property relationship analysis, we explain the origin of the change in the structural parameters and atomic charges in the polar moiety.     

Biomolecule profiles in inedible wild mushrooms with antioxidant value

The use of natural products isolated from mushrooms, included inedible species, against infection, cancer diseases and other oxidative-stress related diseases is one of the cornerstones of modern medicine. In the present work, the antioxidant molecule profiles of inedible mushroom species were evaluated and compared with those of edible species. The order of antioxidant abundance found in inedible wild mushrooms was: phenolics > flavonoids > ascorbic acid > tocopherols > carotenoids, similar to that of edible species. Furthermore the same energetic biomolecules were found including the disaccharide trehalose, the monosaccharide alcohol derivative mannitol and the fatty acids palmitic, oleic and linoleic acids. Fomitopsis pinicola revealed a very high phenolics concentration (388 mg GAE/g extract) and powerful antioxidant properties, mainly reducing power (EC??) value 60 μg/mL similar to the standard Trolox?). It could find applications in the prevention of free radical-related diseases as a source of bioactive compounds.     

Fast synthesis employing a microwave assisted neat protocol of new monomers potentially useful for the preparation of PDLC films

It has been reported that the length of the molecular chain and the rigidity of molecules influence the structure of the polymer network in PDLC films and hence the electro-optical properties of the composites. Herein, a series of new aromatic monomeric monomethacrylates, bismethacrylates and monovinylbenzene derivatives with a mesogenic core were successfully synthesized under microwave irradiation. The microwave assisted synthesis resulted in decreased reaction times, reduced solvent requirement, increased operational simplicity, and in most cases, improved yields and selectivity.      

Nanocarbon-Iridium Oxide Nanostructured Hybrids as Large Charge Capacity Electrostimulation Electrodes for Neural Repair

Nanostructuring nanocarbons with IrO_x yields to material coatings with large charge capacities for neural electrostimulation, and large reproducibility in time, that carbons do not exhibit. This work shows the contributions of carbon and the different nanostructures present, as well as the impact of functionalizing graphene with oxygen and nitrogen, and the effects of including conducting polymers within the hybrid materials. Different mammalian neural growth models differentiate the roles of the substrate material in absence and in presence of applied electric fields and address optimal electrodes for the future clinical applications.     

Effect of substrate’s nature on the growth of HgBCCO thin films

The synthesis of HgBCCO films by spray pyrolysis on single crystals is investigated. It is shown that in conditions where the precursor is expected to give Hg-1223, Hg-1212 grows on LaAlO₃ (0 0 1) while Hg-1223 grows on MgO (0 0 1). The samples are analysed by X-ray pole figures, SEM and critical current measurements. Both samples were superconducting but the sample on MgO had a negligible I_c while 17 A was measured on LAO at 77 K (sf). These differences are analysed in terms of texture and microstructure and some conclusions concerning the growth are drawn. On LAO, the nucleation is probably epitaxial and the anisotropy of the growth inhibits the transformation into Hg-1223 while some interfacial contribution expected to occur on MgO makes this transformation easier.     

Magnetic,Spectroscopic and Thermal Study of [Cu(NO3)(PyTz)2](NO3). A Copper(II) Complex Containing Thiazine Derivative Ligand

The copper(II) complex [Cu(NO₃)(PyTz)₂](NO₃) has been previously characterized means X‐ray powder diffraction and now studied by IR spectroscopy, UV‐Vis‐NIR diffuse reflectance, magnetic susceptibility measurement, electronic spin resonance (ESR) and thermal analysis. The results are correlated with a distorted square pyramidal coordination around copper(II) ion rather than the cis‐distorted octahedral stereochemistry of a CuN₄OO′ chromophore in good concordance with their structure. Likewise, in order to indicate towards what square pyramidal isomer the complex is distorted, the method proposed by Carugo and Bisi has been applied to the structural data of [Cu(NO₃)(PyTz)₂](NO₃). It is deduced that there is a large distortion from the trigonal bipyramid geometry, close to a square pyramid geometry, being produced almost exclusively through the B route of the Berry mechanism.     

Closed free hyperelastic curves in the hyperbolic plane and Chen-Willmore rotational hypersurfaces

We show that closed Chen-Willmore rotational hypersurfaces of nonnegative curved real space forms are shaped on closed hyperelastic curves of the hyperbolic plane. Then, we study the variational problem associated to this class of curves, proving that there exist a rationally dependent family of closed solutions. They give rise to the first non-trivial examples of Chen-Willmore hypersurfaces in real space forms. Research partially supported by a MCYT-FEDER grant No. BFM2001-2871-C04 and by a UPV grant 9/UPV00127.310-13574/01.