Encapsulated guests, energy transfer

Moreover, these dendrimers proved to be good hosts for anionic dye molecules. Films prepared from these host-guest complexes showed efficient ( > 90%) energy transfer from the OPV units to the encapsulated dye molecules... 

In the presence of visible light irradiation provided by a 120 W lamp and with 1 atm of O2, the Ru(II) complex in solution promoted the oxidation of dibutyl sulfide to the corresponding dibutyl sulfoxide obtained in 32% yield. Under identical experimental conditions but in the presence of the capsule, the reaction did not occur as a consequence of the encapsulation of the Ru(ll) photocatalyst. The catalytic activity was restored when repeating the same experiment with [Ru(bpy)3] in the presence of both capsule and tetraethylam-monium competitive guest, due to the displacement of the metal catalyst from the cavity of the capsule. Similar results were observed with other thioethers showing conversions to the corresponding sulfoxides that were dependent on the electron density on the sulfur atom in all cases, no conversion was observed with the encapsulated Ru(ll) catalyst. Since it was danonstrated that the absorption properties of the Ru(ll) metal center were substantially not influenced by the capsule, it is likely that the inactivation provided by the capsule could be due to interrupted energy transfer from the Ru(ll) center to O2. 

While several researchers have investigated energy transfer from a host (often the dendron itself) to a guest at the core of the dendrimer, there are few examples of guests that are not covalently bound but encapsulated in... 

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