ZnO-Porphyrin Composite Nanostructures as Discriminating Adducts for Metallic Ions in Aqueous Matrices

摘要

abstract_textpTetrapyrrolic macrocycles are largely used in the sensing of various analytes both in liquid and in gaseous phase, but the strong electronic delocalization of this class of molecules makes difficult to realize a selective active layer. To overcome this problem, in the present work it is proposed the synthesis of a supramolecular adduct of zinc oxide nanostructure and a freebase tetra-pyridyl substituted porphyrin. The electronic structure of the two organic/inorganic compounds allows to observe a surface-enhanced Raman scattering (SERS) of the porphyrin vibrational bands. This phenomenon is quenched by the presence of mercuric and cupric ions according to two different mechanisms monitored and explained by means of time resolved fluorescence spectroscopy. It was demonstrated that other substances in complex matrices, such as the food extracts, do not affect the electronic communication between ZnO and porphyrin preserving the SERS effect and minimizing the effect of interfering compounds./p/abstract_text