Photoinduced Energy and Electron Transfer Between a Photoactive Cage Based on a Thermally Activate Delayed Fluorescence Ligand and Encapsulated Fluorescent Dyes

Abstract

The vast majority of polyhedral assemblies prepared by combining organic bent ligands and "photophysically innocent" palladium(II) metal ions are non-emissive. Here we report a simple strategy to switch on the luminescence properties of a polyhedral assembly by combining a Thermally Activated Delayed Fluorescence (TADF) organic emitter based on a dipyridylcarbazole ligand scaffold with Pd 2+ ions, giving rise to a luminescent Pd 6 L 12 molecular cube. The assembly is capable of encapsulating within its cavity up to three molecules per cage of Fluorescein, in its neutral lactone form, and up to two molecules of Rose Bengal in its dianionic quinoidal form. Photoinduced electron Transfer (PeT) between the photoactive cage and the encapsulated Fluorescein and Photoinduced Energy Transfer (PET) from the cage to encapsulated Rose Bengal have been observed by steady-state and time-resolved emission spectroscopy. Introduction.

Photoactive supramolecular cages incorporating Ru(ii) and Ir(iii) metal complexes

“…70 For both Ru11 and Ru12 a chemically reversible Ru II/III oxidation was observed at E ox 1/2 = 1.31 V and E ox 1/2 = 1. 32 (Figure 14). In summary, cage compounds incorporating ruthenium complexes generally maintain the redox properties associated with the ruthenium chromophores.…”

“…This immediately opens the door to many possible applications such as sensing and photocatalysis involving bound guests that can photophysically interact with the emitting hosts. Indeed, incorporation of fluorescent emitters such as porphyrins and BODIPYs, 19a, 30 -conjugated organic compounds, 31 and more recently thermally activated delayed fluorescent emitters (TADF) 32 into the ligand backbone of cages and macrocycles have been shown to give rise to luminescent cages and macrocycles. 29b, 30c, 33 Less studied are supramolecular cages incorporating d-block transition metal complexes such as ruthenium(II), iridium(III), platinum(II), rhenium(I), gold(I), silver(I), rhodium(III) and osmium(II) complexes.…”

Redox‐Guest‐Induced Multimode Photoluminescence Switch for Sequential Logic Gates in a Photoactive Coordination Cage

“…Especially, photophysical and photochemical behaviors related to the confined and oriented electron transfer (ET) or energy transfer (EnT) processes in MOCs are intriguing because these approaches offer opportunities for the development of novel light‐harvesting, light‐emitting and photosynthesizing materials. Meanwhile, specific interactions between MOCs and guest molecules can interfere with the photoelectronic processes, and trigger changes in PL intensity or emitting positions of the MOCs . In this way, a PL responsive integrated system can be established based on the principles of supramolecular chemistry by utilizing the host–guest interactions to modulate ET/EnT processes.…”

“…Meanwhile, specific interactions between MOCs and guest molecules can interferew ith the photoelectronic processes, and trigger changesi nP Li ntensity or emitting positions of the MOCs. [11][12][13] In this way,aP Lr esponsivei ntegrated system can be established based on the principles of supramolecular chemistry by utilizing the host-guesti nteractions to modulate ET/EnTp rocesses.…”

Confinement of a Au–N-heterocyclic carbene in a Pd6L12 metal–organic cage

“…39324 | RSC Adv., 2020,10,[39323][39324][39325][39326][39327] This journal is © The Royal Society of Chemistry 2020RSC Advances Paper Open Access Article. Published on 27 October 2020.…”