Supramolecular structures with luminescent properties. Molecular recognition studies.

Abstract

Supramolecular chemistry focusses on the study of the weak intermolecular interactions between molecules. Among the great variety of molecular recognition processes, anion sensing deserves a special attention, since it is well known that anions are involved in many areas of both chemical and biological significance. In order to explore the fundamental chemistry of 5f-elements and their application in anion sensing, uranyl-salophen complexes were studied in this work. These complexes used a vacant coordination site in the equatorial plane to bind anions in terms of a Lewis acid-base interaction. In particular, we present our study of molecular recognition of fluoride and chloride anions using two different uranyl-salophen complexes that differ in the position of the tert-butyl substituent in two organic solvents: dichloromethane and chloroform. On the other hand, in order to obtain water soluble species that can be used in molecular recognition processes, the research developed in this area is based on self-assembly reactions to obtain heterometallic macrocycles. For this purpose, three polyamine ligands that contain two N-donor units (pyridine) at the end positions and [Pt(en)(NO3)2] and [Pd(en)(NO3)2] complexes were used as precursors. Due to the intrinsic luminescent properties of most of the nitrogenate ligands, spectrophotometric and spectrofluorimetric titrations were performed in order to follow the formation of the macrocycles.