Juan Teodomiro López-Navarrete

DNA-chlorpheniramine interaction studied by spectroscopic techniques

It was previously studied that the antihistaminic chlorpheniramine elicits a biphasic response on cell growth and regulates polyamine metabolism, as described for polyamines. In part, polyamine effects on macromolecular synthesis and cell growth are attributed to nucleic acid:polyamine interactions. In this work, we have tested the hypothesis of a DNA:chlorpheniramine interaction, using fluorometry, FTIR and Raman spectroscopic techniques. The results indicate that DNA:chlorpheniramine interaction occurs inducing conformational changes in the macromolecule by affecting both phosphodiester bonds and bases. Results open new perspectives for characterization of action mechanisms of natural or synthetic diamines with pharmacological or physiological importance.

Modulation of the exfoliated graphene work function through cycloaddition of nitrile imines

After the feasibility of the 1,3-dipolar cycloaddition reaction between nitrile imines and exfoliated graphene by density functional theory calculations was proved, very few-layer graphene was effectively functionalized using this procedure. Hydrazones with different electronic properties were used as precursors for the 1,3-dipoles, and microwave irradiation as an energy source enabled the reaction to be performed in a few minutes. The anchoring of organic addends on the graphene surface was confirmed by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis. Ultraviolet photoelectron spectroscopy (UPS) was used to measure the work function and band gap of these new hybrids. Our results demonstrate that it is possible to modulate these important electronic valence band parameters by tailoring the electron richness of the organic addends and/or the degree of functionalization.