Systematic Studies on 3d- and 4f-Metal Containing Polyoxometalates Suitable for Organic Derivatization

Resumo

The organic derivatization of polyoxometalates (POMs) has been identified as a key factor for these anionic metal-oxo clusters to be suitably incorporated into different materials. In the first part of this work, systematic studies on the organic functionalization of the [{M(H2O)3}2(WO2)2(SbW9O33)2]10- Krebs-type POMs are discussed. As a result, 11 novel hybrid POMs have been synthesized and characterized by elemental and thermal analyses, FT-IR spectroscopy and single-crystal X-ray diffraction. Moreover, their solution behavior has also been studied by 1H-NMR and electrospray ionization-mass spectrometry (ESI-MS). The second part of this dissertation includes the synthesis of new POM clusters with accessible 3d- and 4f-metal centers suitable for further organic derivatization. In a first stage, the preparation of four series of 4f-metal containing assemblies is reported, whereas the heterometallic 3d-4f clusters obtained from the reaction of Krebs-type POMs with lanthanides are described later on. The 28 novel POMs have also been characterized by elemental and thermal analyses, FT-IR spectroscopy and single-crystal X-ray diffraction. Some interesting properties of these clusters, such as photoluminescence or magnetism have also been analyzed. The solution behavior has been studied by a combination of ESI-MS experiments and 183W-NMR spectroscopy. Furthermore, the highly charged and gigantic lanthanide containing tungstogermanates obtained in this section have shown the ability to self-assemble in solution into hollow, single-layered and vesicle-like blackberry-type structures. The formation of the blackberries has been monitored by laser light scattering techniques (dynamic light scattering and static light scattering) and its hollow and spherical nature has been confirmed by TEM images.