Photoactive metallocyclodextrins: sophisticated supramolecular arrays for the construction of light activated miniature devices

Abstract

The introduction of photoactive metal centres onto cyclodextrin receptors opens up new possibilities for the design of sensors, wires and energy conversion systems. This tutorial review focuses on strategies involving such metallocyclodextrins for the construction of supramolecular arrays with light-activated functions. The assembly procedures for building such arrays are presented, together with the features required for their functions both as sensors for ion or small molecule detection and as wires for photoinduced long-range energy or electron transport. Systems for metal ion sensing are described where the cyclodextrin plays a mediating role in influencing the luminescence properties of an organic probe, responsive to metal binding. Small molecule sensing by the cyclodextrin cavity is realised using luminescent lanthanide or transition metal functionalised cyclodextrins. The light signal of the photoactive metal is switched on or off upon binding an analyte in the cyclodextrin cavity. The metallocyclodextrin systems that function as wires are distinguished by the controlled assembly of transition metal polypyridine and metalloporphyrin units. These units have inherent photoactivity that defines the vectorial direction of energy or electron transfer processes through the wire.

Uni‐molecular detection and quantification of selected β‐lactam antibiotics with a hybrid α‐hemolysin protein pore

“…By doing so, it was demonstrated that many chromophore-modified CDs are capable of changing fluorescence and absorption intensities upon inclusion of a guest molecule, and these spectral variations were seen to take place following induced-fit conformational changes of the hosts (Ueno et al, 1990(Ueno et al, , 1992Minato et al, 1991;Kuwabara et al, 1994;Corradini et al, 1996). Other groups have focused on photoactive metal ion-ligand appended CDs, metallocyclodextrins (Haider and Pikramenou, 2005), and applied as chemical sensors. For a very good review on such work please see Ogoshi and Harada (2008).…”

Synthesis and NMR characterization of β‐alanine‐bridged hemispherodextrin, a very efficient chiral selector in EKC

“…Due to their relatively apolar cavities and to their solubilities in water, they can be used in an aqueous solution to interact with apolar molecules, as well as with apolar moieties of amphiphilic molecules, in a variety of different applications [5][6][7]. These characteristics are related to their saccharidic nature, together with the particular spatial disposition of their cyclic chain, with polar groups on the external surface.…”

Ultrasensitive and Signal‐on Electrochemiluminescence Aptasensor Using the Multi‐tris(bipyridine)ruthenium(II)‐β‐cyclodextrin Complexes

“…[35,36] To date, metallocyclodextrins have generally been used in metal ion sensors, [37,38] small molecule detectors [39] and electron transport wires. [40] However, most of these reports are based on fluorescent phenomena related to the recognition between the cyclodextrin cavity and various guests.…”