Highly efficient photosensitizers with aggregation-induced emission characteristics obtained through precise molecular design

Abstract

We herein report a new strategy to obtain highly efficient photosensitizers (PSs) by reducing the singlet-triplet energy gap (ΔE) and blocking the non-radiative decay pathways. Through precise molecular design, TP1-8 were synthesized to exhibit predictable properties including moderate to high photosensitizing efficacy, tunable absorption and emission wavelengths and aggregation-induced emission characteristics.

Far‐Red/Near‐Infrared Emissive (1,3‐Dimethyl)barbituric Acid‐Based AIEgens for High‐Contrast Detection of Metastatic Tumors in the Lung

“…Some key synthesis steps are described as follows. Both the compounds 2 and 6 were obtained by Suzuki–Miyaura coupling reaction . Compound 4 was synthesized as a yellow solid by Stille coupling reaction between 1 and 3 in 75 % yield.…”

“…Both the compounds 2 and 6 were obtainedb yS uzuki-Miyaura coupling reaction. [17,18] Compound 4 was synthesized as ay ellow solid by Stille coupling reaction between 1 and 3 in 75 %y ield. The compounds 2, 4,a nd 6 were then reacted with (1,3-dimethyl)barbituric acidv ia Knoevenagel condensation to afford TPE-Ph-B, TPE-ETh-B, and TPE-Th-B, respectively, in moderate yields rangingf rom 60-69 %.…”

Membrane‐Anchoring Photosensitizer with Aggregation‐Induced Emission Characteristics for Combating Multidrug‐Resistant Bacteria

“…The PS sensitivity or its effectiveness in ROS production is highly dependent on its capability in light absorption and intersystem crossing (ISC) . ISC can be adjusted through HOMO–LUMO engineering to realize a small energy gap between the triplet (T1) and singlet (S1) states.…”

Self-assembled nanostructured photosensitizer with aggregation-induced emission for enhanced photodynamic anticancer therapy

“…An efficient intersystem crossing (ISC) rate (K ISC ) from the lowest excited state (S 1 ) to the lowest triplet state (T 1 ) increased the 1 O 2 production ability of PS, and large spin-orbit coupling (SOC) as well as a small ∆E ST (the energy gap between singlet and triplet states) could enhance K ISC [49][50][51][52]. To improve the photosensitization of AIEgen PSs, strong electron accepting and donating groups were introduced on different sides of AIEgens' skeleton to construct donor-acceptor (D-A), donor-acceptor-donor (D-A-D), or acceptor-donor-acceptor (A-D-A) systems for accurate tuning of the highest-energy occupied molecular orbital (HOMO) and lowest-energy unoccupied molecular orbital (LUMO) to minimize the ∆E ST [11,[37][38][39][53][54][55]. Another way to minimize ∆E ST is to insert conjugated moieties as a linker between donor and acceptor moieties to lengthen the HOMO-LUMO space for efficient 1 O 2 production capability of PSs.…”