Clar's Aromatic π-Sextet Rule for the Construction of Red Multiple Resonance Emitter.

Despite the proliferation of multiple resonance (MR) materials in the blue to green spectral ranges, red MR emitters remain scarce in the literature, an area that certainly warrants attention for future applications. Here, through a clever application of classic Clar's aromatic π-sextet rule, we triumphantly constructed the first red MR emitter by substituting the conventional benzene ring core with anthracene (fewer π-sextets). Theoretical studies indicate that the quantity of π-sextets ultimately determines the optical band gap of a molecule, rather than the number of fused benzene rings.

Cascade Effect of a Dimerized Thermally Activated Delayed Fluorescence Dendrimer.

Thermally activated delayed fluorescence (TADF) emitters with a high horizontal orientation are highly essential for improving the external quantum efficiency (EQE) of organic light-emitting diodes; however, pivotal molecular design strategies to improve the horizontal orientation of solution-processable TADF emitters are still scarce and challenging. Herein, a phenyl bridge is adopted to connect the double TADF units, and generate a dimerized TADF dendrimer, D4CzBNPh-SF. Compared to its counterpart with a single TADF unit, the proof-of-the-concept molecule not only exhibits an improved horizontal dipole ratio (78 %) due to the π-delocalization-induced extended molecular conjugation, but also displays a faster reversed intersystem crossing rate constant (6.

Single Wavelength Laser Excitation Ratiometric NIR-II Fluorescent Probe for Molecule Imaging in Vivo.

Fluorescence (FL) imaging in the second near-infrared window (NIR-II, 1000-1700 nm) has emerged as a promising bioimaging modality that enables noninvasive visualization of deep tissue with an unprecedented resolution. However, there is a paucity of studies on high-quality responsive NIR-II FL molecules. Herein we report a novel activated NIR-II FL molecule, 4,7-bis(5-(4-(diphenylamine)phenyl)-2-thiophene) [1,2,5]selenadiazolo[3,4-]benzo[][1,2,5]thiadiazole (SeTT), which exhibits fast and specific responsive capability to hypochlorous acid (HClO).

Dye-Modified Metal-Organic Framework as a Recyclable Luminescent Sensor for Nicotine Determination in Urine Solution and Living Cell.

A water-stable and pH-independent sensor for qualitative and quantitative detection of nicotine in urine solution and living cell was successfully developed. This material, named MB@UiO-66-NH, can be synthesized by encapsulating methylene blue (MB) with a well-known metal-organic framework (MOF) UiO-66-NH through a simple impregnation method. The fluorescence intensity of the system was significantly enhanced when a certain amount of nicotine was added.