Donor–acceptor fluorophores as efficient energy transfer photocatalysts for [2 + 2] photodimerization

Abstract

Donor–acceptor fluorophores can act as efficient energy transfer photocatalysts to activate enone substrates, realizing photodimerization and isomerization reaction of enone substrates without precious metal photocatalysts.

Organic thermally activated delayed fluorescence (TADF) compounds used in photocatalysis

“…179). 362 This reaction is known to proceed via a Dexter energy transfer mechanism with fac-Ir(ppy) 3 as the photosensitizer. 363 Ten TADF compounds were considered as PCs in this reaction: 4CzIPN, 4CzIPN-t Bu, 4CzIPN-Ph, 4CzIPN-OMe, 4CzPN, 4CzPN-t Bu, 4CzPN-Ph, 5CzBN, 5CzBN-OMe and 3DPAFIPN, all of which giving yields ranging from 60-71%, except 4CzIPN-OMe, which managed only 23%.…”

Thermally Activated Delayed Fluorescence Sensitizers As Organic and Green Alternatives in Energy-Transfer Photocatalysis

“…Similar to Koenig's work, Luo and co-workers reported a [2 + 2] photodimerization process involving chalcone scaffolds (Scheme 2A). 94 The methodology developed improves upon Liebermann's original direct-sensitization method from 1877, 95 with drastic improvements in yield and expanded functional group tolerance. In this study, tBu-4CzIPN sensitizes both cis and trans olefins, whereby the excited triplet state forms a biradical.…”

4,7-Diarylbenzo[c][1,2,5]thiadiazoles as fluorophores and visible light organophotocatalysts

“…Organic π-conjugated electron donor-acceptor (D-A) systems have firmly established themselves as a powerful design motif for applications such as organic photovoltaics, fluorophores and photocatalysts. [1][2][3][4] Among the endless combinations of donor and acceptor groups, the benzo[c] [1,2,5]thiadiazole (BTZ) motif has received appreciable attention as a strongly electron accepting moiety, primarily for use in photovoltaic applications but also as fluorescent sensors or bioimaging probes for lipid droplets, mitochondria and plasma membranes. [5][6][7][8][9][10][11][12] The BTZ group has also been researched for photocatalytic applications although this has mainly been limited to heterogeneous systems involving BTZ containing metal-organic frameworks (MOFs), [13][14][15] covalent organic frameworks (COFs), [16][17][18] and conjugated porous polymers (CPPs).…”