Molecular Devices: Energy Transfer

Abstract

Devices are systems able to perform specific functions, which result from the coordinated action of different components. The design of these systems is, hence, based on the identification or the development of the necessary parts, and in their integration in a suitable supramolecular architecture. The main challenge in such a process is undoubtedly synthetic: the control of the mutual interactions between the active moieties, in fact, requires a fine‐tuning of the distance and orientation of the components and, in the case of physically connected donor‐acceptor moieties, of the electronic properties of the interconnecting linkers. Organization through covalent bonding has, in this context, several advantages, and many examples of covalent supramolecular devices have been reported in the last two decades. Besides, the covalent approach led to the design of fascinating and efficient prototypes, that often require the preparation of beautiful but complicated chemical systems, through time‐demanding multistep synthetic paths and that are not suitable for large‐scale production. Many examples of devices derived from a more traditional supramolecular approach based on self‐assembly and host‐guest interactions have also been reported. In this chapter, some relevant examples of both covalent and self‐organizing supramolecular devices based on energy‐transfer (ET) processes are reviewed. The basic principles of ET are also discussed. Recently, the advent of nanomaterials offered to supramolecular chemists new active components and structural platforms suitable for the design of nanometric molecular devices. At the present stage, nanomaterials represent, in fact, an ideal platform to achieve a reasonable degree of spatial organization especially when the integration of a large number of components is required or desired. This approach allows the achievement of complex, extensive devices otherwise not accessible. Moreover, some nanomaterials have unique photophysical properties and can become themselves active nanosized component of the final device. In this chapter, we discuss selected examples of ET‐based supramolecular devices with increasing complexity and size; going from dyads to multicomponent nanostructures.

LIBS e nanopartículas fluorescentes

“…Uma destas estratégias consiste na imobilização de reagentes luminescentes na matriz de sílica por encapsulamento. Esta categoria de nanopartícula é conhecida como DDSN (do inglês, Dye-Doped Silica Nanoparticle) (Díaz-García & Dios, 2010; Liang et al, 2010;Bonacchi et al, 2011).…”

“…Dada sua importância, o design destes sensores tem sido amplamente discutido pela comunidade científica, conseqüentemente, numerosas revisões sobre este assunto têm sido disponibilizados na literatura (Prodi, 2005;Wang et al, 2006;Liang et al, 2010;Bonacchi et al, 2011;Prodi et al, 2011).…”

“…As nanopartículas de sílica atuam como suporte sólido e podem ser dopadas com diferentes tipos de reagentes luminescentes, tal como os complexos de rutênio (Moreno-Bondi et al, 1998;Orellana et al, 1999;Glomm et al, 2005;Tfouni et al, 2010). Essa classe de nanopartículas pode se estabelecer como uma nova alternativa para determinação de íons metálicos em amostras com aplicação biológica, toxicológica e ambiental (Wiesner & Burns, 2006;Bonacchi et al, 2011;Prodi et al, 2011).…”