Polyoxometalate-Based Hybrids with 3d- and 4f-Metal Complexes Bearing Multidentate Organic Ligands From Magnetoluminescent Molecular Species to Extended Frameworks with Sorption Ability

Abstract

This dissertation explores the reactivity of polyoxometalates (POMs) - a well-known class of anionic metal-oxo clusters- towards 3d- or 4f-metal complexes of multidentate organic ligands. In the first part of this work, the influence of the pH on the polyoxomolybdate/{Cu(cyclam)}2+ (cyclam = 1,4,8,11-tetraazacyclotetradecane) synthetic system is evaluated. As a result, 4 different extended structures containing hepta- or octamolybdate anions have been synthesized, and chemical and structurally characterized. Moreover, their thermostructural behavior has been analyzed, which reveals the ability to undergo sequential thermally-triggered single-crystal-to-single-crystal transformations. Selective water and gas sorption properties have also been studied for anhydrous phases. Furthermore, the effect of the different aqueous reaction media on the assembly of Anderson-Evans/{Cu(DMC)}2+ (DMC = 1,8-dimethylcyclam) synthetic system has also been studied. The new 7 hybrid compounds with different dimensionalities have been characterized and their thermostructural behavior analyzed.The second part of this work includes the derivatization of mid-to-late 4f-metal-substituted Keggin-type POMs with compartmental organic ligands. The 10 novel molecular POMs have been chemical and structurally characterized. Some interesting properties of these clusters, such as photoluminescence or the slow relaxation of magnetization have also been analyzed and their solution behavior assessed by a combination of ESI-MS experiments and 1H-NMR spectroscopy.