High-efficiency triplet-triplet annihilation upconversion microemulsion with facile preparation and decent air tolerance.

Current research of triplet-triplet annihilation upconversion (TTA-UC) faces difficulty such as overuse of organic solvents and quenching of excited triplet sensitizers by molecular oxygen. Herein, we propose an efficient and facile preparation strategy of TTA-UC microemulsion to overcome these issues. With simple device and short preparation process, air-stable TTA-UC with a high upconversion efficiency of 16.52% was achieved in microemulsion coassembled from TritonX114, tetrahydrofuran and upconverting chromophores (platinum octaethyl-porphyrin and 9,10-diphenylanthracene). This is comparable to the highest UC efficiency ever reported for TTA-UC microemulsion systems. The excellent UC performance of TX114-THF could be attributed to two perspectives. Firstly, small-size micelle accommodated chromophores up to high concentrations in organic phase, which promoted efficient molecular collision. Additionally, high absorbance at 532 nm ensured full use of excitation light, getting more long wavelength photons involved in the TTA-UC process. Moreover, air-stable TTA-UC also performed well in microemulsion with various surfactants, including nonionic surfactants (Tween 20, Tween 80, Triton X-110, Triton X-114), ionic surfactants (sodium dodecyl sulfate, cetyltrimethyl ammonium bromide) and block copolymers (pluronic F127, pluronic P123), through three conjectural assembly models according to the structural characteristics of surfactant molecules (concentrated, uncompacted and scattered). These discoveries could provide estimable reference for selection of surfactants in relevant fields of TTA-UC.

Novel Photocatalyst Based on Through-Space Charge Transfer Induced Intersystem Crossing Enables Rapid and Efficient Polymerization Under Low-Power Excitation Light.

Currently, most photoredox catalysis polymerization systems are limited by high excitation power, long polymerization time, or the requirement of electron donors due to the precise design of efficient photocatalysts still poses a great challenge. Herein, we propose a new approach: the creation of efficient photocatalysts having low ground state oxidation potentials and high excited state energy levels, along with through-space charge transfer (TSCT) induced intersystem crossing (ISC) properties. A cabazole-naphthalimide (NI) dyad (NI-1) characterized by long triplet excited state lifetime (τT=62 µs), satisfactory ISC efficiency (ΦΔ=54.3 %) and powerful reduction capacity [Singlet: E1/2 (PC+1/*PC)=-1.93 eV, Triplet: E1/2 (PC+1/*PC)=-0.84 eV] was obtained. An efficient and rapid polymerization (83 % conversion of 1 mM monomer in 30 s) was observed under the conditions of without electron donor, low excitation power (10 mW cm-2) and low catalyst (NI-1) loading (<50 µM). In contrast, the conversion rate was lower at 29 % when the reference catalyst (NI-4) was used for photopolymerization under the same conditions, demonstrating the advantage of the TSCT photocatalyst. Finally, the TSCT material was used as a photocatalyst in practical lithography for the first time, achieving pattern resolutions of up to 10 µm.

Ru(II)-Catalyzed Divergent C-H Alkynylation Cascade with Bifunctional α-Alcohol Haloalkynes.

Native functionality directed the C-H activation cascade to enable rapid construction of molecular complexity, featuring step-economy and synthetic efficiency. Herein, by exploiting bifunctional α-alcohol haloalkynes, we developed Ru(II)-catalyzed carboxylic acid, amine, and amide assisted divergent C-H alkynylation and annulation cascade, affording polyfunctional heterocycles. Significantly, a bilateral aryl C-H polycyclization cascade of azobenzenes was achieved using the versatile haloalkynes.

Precise molecular engineering for the preparation of pyridinium photosensitizers with efficient ROS generation and photothermal conversion.

Organic photosensitizers (PSs) with aggregation-induced emission properties have great development potential in the integrated application of multi-mode diagnosis and treatment of photodynamic therapy (PDT) and photothermal therapy (PTT). However, preparing high-quality PSs with both optical and biological properties, high reactive oxygen species (ROS) and photothermal conversion ability are undoubtedly a great challenge. In this work, a series of pyridinium AIE PSs modified with benzophenone have been synthesized. A wide wavelength range of fluorescent materials was obtained by changing the conjugation and donor-acceptor strength. TPAPs5 has a significant advantage over similar compounds, and we have also identified the causes of high ROS generation and high photothermal conversion in terms of natural transition orbitals, excited state energy levels, ground-excited state configuration differences and recombination energy. Interestingly, migration of target sites was also found in biological imaging experiments, which also provided ideas for the design of double-targeted fluorescent probes. Therefore, the present work proposed an effective molecular design strategy for synergistic PDT and PTT therapy.

Ag-Catalyzed Practical Synthesis of N-Acyl Anthranilic Acids from Anthranils and Carboxylic Acids.

A practical synthesis of valuable N-acyl anthranilic acids has been achieved via a silver-catalyzed imino-ketene generation from readily available anthranils and carboxylic acids. A wide range of carboxylic acids including sterically demanding aliphatic carboxylic acids, aromatic carboxylic acids, acrylic acids, and amino acids are compatible in this reaction. Moreover, this method can be used to modify drug molecules and natural products, such as ibuprofen, probenecid, and acetylglycine.

Red-light operable photosensitizer with symmetry-breaking charge transfer induced intersystem crossing for polymerization of methyl methacrylate.

We present a red light-activated zincII bis(dipyrrin) symmetry breaking charge transfer (SBCT) architecture, showing a large molar absorption coefficient (ε = 15.4 × 104 M-1 cm-1), high reactive singlet oxygen generation efficiency (ΦΔ ≈ 0.8) and long-lived triplet state (τT = 150 µs) compared to the donor-acceptor analogue dipyrrin-BF2 complex, highlighting the superiority of the SBCT approach. For the first time, we demonstrated the potential of a SBCT scaffold in red-light-induced methyl methacrylate (MMA) polymerization, using a dual photocatalyst excitation approach.

Synergetic Modulation of Steric Hindrance and Excited State for Anti-Quenching and Fast Spin-Flip Multi-Resonance Thermally Activated Delayed Fluorophore.

Multi-resonance thermally activated delayed fluorescence (MR-TADF) materials hold great promise for advanced high-resolution organic light-emitting diode (OLED) displays. However, persistent challenges, such as severe aggregation-caused quenching (ACQ) and slow spin-flip, hinder their optimal performance. We propose a synergetic steric-hindrance and excited-state modulation strategy for MR-TADF emitters, which is demonstrated by two blue MR-TADF emitters, IDAD-BNCz and TIDAD-BNCz, bearing sterically demanding 8,8-diphenyl-8H-indolo[3,2,1-de]acridine (IDAD) and 3,6-di-tert-butyl-8,8-diphenyl-8H-indolo[3,2,1-de]acridine (TIDAD), respectively. These rigid and bulky IDAD/TIDAD moieties, with appropriate electron-donating capabilities, not only effectively mitigate ACQ, ensuring efficient luminescence across a broad range of dopant concentrations, but also induce high-lying charge-transfer excited states that facilitate triplet-to-singlet spin-flip without causing undesired emission redshift or spectral broadening. Consequently, implementation of a high doping level of IDAD-BNCz resulted in highly efficient narrowband electroluminescence, featuring a remarkable full-width at half-maximum of 34 nm and record-setting external quantum efficiencies of 34.3 % and 31.8 % at maximum and 100 cd m-2, respectively. The combined steric and electronic effects arising from the steric-hindered donor introduction offer a compelling molecular design strategy to overcome critical challenges in MR-TADF emitters.

Photoredox-Mediated Aerobic Oxidative Cleavage of 1,3-Diketones to Access 1,2-Diketones and (Z)-1,4-Enediones.

An aerobic oxidative cleavage of 1,3-diketones under visible light irradiation using an organic dye as a photocatalyst is disclosed. The newly developed reaction provides practical access to 1,2-diketones and (Z)-1,4-enediones in moderate to good yields with absolute regio- and stereoselectivity. Mechanistic studies of the reaction suggest that tetraketone intermediates might undergo a photocatalytic energy transfer from the excited photocatalyst to form biradical-like (n,π*) states of ketones.

Improving the Efficiency and Stability of MAPbI3 Perovskite Solar Cells by Dipeptide Molecules.

Passivating the electronic defects of metal halide perovskite is regarded as an effective way to improve the power conversion efficiency (PCE) of perovskite solar cells (PVSCs). Here, a series of dipeptide molecules with abundant ─C═O, ─O─ and ─NH functional groups as defects passivators for perovskite films are employed. These dipeptide molecules are utilized to treat the surface of prototype methyl ammonium lead iodide (MAPbI3 ) films and the corresponding PVSCs exhibit enhanced photovoltaic performance and ambient stability, which can be ascribed to: 1) the ─C═O and ─O─ can interact with the undercoordinated Pb2+ ions and the ─NH groups can form hydrogen bonds with the I- ions, passivating the defects in perovskite film and reducing charge recombination in PVSCs; 2) the long alkyl chain of dipeptide molecules increases the hydrophobicity of the perovskite surface and thus enhance the stability of PVSCs. The passivated MAPbI3 -based PVSCs exhibit a champion PCE of 20.3% and retain 60% of the initial PCE after 1000 h. It is believed that the defects passivation engineering using polypeptide moleculars can be applied in other perovskite compositions for high device efficiency and stability.

New [3+2+1] Iridium Complexes as Effective Phosphorescent Sensitizers for Efficient Narrowband Saturated-Blue Hyper-OLEDs.

Two newly designed and synthesized [3+2+1] iridium complexes through introducing bulky trimethylsiliyl (TMS) groups are doped with a terminal emitter of v-DABNA to form an coincident overlapping spectra between the emission of these two phosphors and the absorption of v-DABNA, creating cascade resonant energy transfer for efficient triplet harvesting. To boost the color quality and efficiency, the fabricated hyper-OLEDs have been optimized to achieve a high external quantum efficiency of 31.06%, which has been among the highest efficiency results reported for phosphor sensitized saturated-blue hyper-OLEDs, and pure blue emission peak at 467 nm with the full width at half maxima (FWHM) as narrow as 18 nm and the CIEy values down to 0.097, satisfying the National Institute of Standards and Technology (NIST) requirement for saturated blue OLEDs display. Surprisingly, such hyper-OLEDs have obtained the converted lifetime (LT50 ) up to 4552 h at the brightness of 100 cd m-2 , demonstrating effective Förster resonance energy transfer (FRET) process. Therefore, employing these new bulky TMS substituent [3+2+1] iridium(III) complexes for effective sensitizers can greatly pave the way for further development of high efficiency and stable blue OLEDs in display and lighting applications.

Efficient Intersystem Crossing and Long-lived Charge-Separated State Induced by Through-Space Intramolecular Charge Transfer in a Parallel Geometry Carbazole-Bodipy Dyad.

The design of efficient heavy atom-free triplet photosensitizers (PSs) based on through bond charge transfer (TBCT) features is a formidable challenge due to the criteria of orthogonal donor-acceptor geometry. Herein, we propose using parallel (face-to-face) conformation carbazole-bodipy donor-acceptor dyads (BCZ-1 and BCZ-2) featuring through space intramolecular charge transfer (TSCT) process as efficient triplet PS. Efficient intersystem crossing (ΦΔ =61 %) and long-lived triplet excited state (τT =186 µs) were observed in the TSCT dyad BCZ-1 compared to BCZ-3 (ΦΔ =0.4 %), the dyad involving TBCT, demonstrating the superiority of the TSCT approach over conventional donor-acceptor system. Moreover, the transient absorption study revealed that TSCT dyads have a faster charge separation and slower intersystem crossing process induced by charge recombination compared to TBCT dyad. A long-lived charge-separated state (CSS) was observed in the BCZ-1 (τCSS =24 ns). For the first time, the TSCT dyad was explored for the triplet-triplet annihilation upconversion, and a high upconversion quantum yield of 11 % was observed. Our results demonstrate a new avenue for designing efficient PSs and open up exciting opportunities for future research in this field.

Red/NIR emissive aggregation-induced emission-active photosensitizers with strong donor-acceptor strength for image-guided photodynamic therapy of cancer.

Light-mediated therapies such as photodynamic therapy (PDT) are considered emerging cancer treatment strategies. However, there are still lots of defect with common photosensitizers (PSs), such as short emission wavelength, weak photostability, poor cell permeability, and low PDT efficiency. Therefore, it is very important to develop high-performance PSs. Recently, luminogens with aggregation-induced emission (AIE) characteristics and red/near-infrared (NIR) emissive have been reported as promising PSs for image-guided cancer therapy, due to them being able to prevent autofluorescence in physiological environments, their enhanced fluorescence in the aggregated state, and generation of reactive oxygen species (ROS). Herein, we developed PSs named TBTCPM and MTBTCPM with donor-acceptor (D-A) structures, strong red/NIR, excellent targeting specificities to good cell permeability, and high photostability. Interestingly, both of them can efficiently generate ROS under white light irradiation and possess excellent killing effect on cancer cells. This study, thus, not only demonstrates applications in cell image-guided PDT cancer therapy performances but also provides strategy for construction of AIEgens with long emission wavelengths.

Molecular engineering to enhance the reactive oxygen species generation of AIEgens and exploration of their versatile applications.

Fluorescent dyes with aggregation-induced emission (AIE) characteristics have shown potential applications in the fields of biological imaging, photodynamic therapy and photothermal therapy, in which photosensitizers (PSs) play a crucial role. However, how to design high-quality PSs with high reactive oxygen species (ROS) generation efficiency remains unclear. In this contribution, an effective molecular design strategy to improve the ROS generation efficiency of AIE PSs was proposed. A series of tetraphenylethylene derivatives containing the pyridine ring or pyridinium with different substituents were designed and synthesized. All the molecules were weakly emissive when molecularly dissolved in solution but displayed intense emission upon aggregation, demonstrating a phenomenon of AIE characteristic. Pyridinium molecules could be used as visualization agents to specifically stain the mitochondria in living cells, while most of the molecules failed to generate ROS upon white light irradiation. In contrast, TPE-Pys-BP containing benzophenone produced ˙OH and 1O2 efficiently in the presence of light due to its large spin-orbit coupling constant to promote efficient intersystem crossing. Such a property allowed TPE-Pys-BP to serve as a PS to kill cancer cells using photodynamic therapy. TPE-Pys-BP also exhibited mechanochromic luminescence (ML), and its emission could be reversibly switched between two distinct colors through repeated grinding and fuming processes. A security paper was fabricated using the ML properties of TPE-Pys-BP.

Tf2O-Promoted Chemoselective C3 Functionalization of Anthranils with Phenols and Thiophenols.

Different chemoselectivities of phenols and thiophenols were observed in a Tf2O-promoted C3 functionalization of simple anthranils. The reaction of phenols and anthranils gives 3-aryl anthranils via a C-C bond formation, whereas thiophenols afford 3-thio anthranils through a C-S bond formation. Both reactions have a broad substrate scope and tolerate a wide range of functional groups, affording the corresponding products with specific chemoselectivity.

Corrigendum: Diversity and heterogeneity in human breast cancer adipose tissue revealed at single-nucleus resolution.

[This corrects the article DOI: 10.3389/fimmu.2023.1158027.].

Diversity and heterogeneity in human breast cancer adipose tissue revealed at single-nucleus resolution.

Introduction: There is increasing awareness of the role of adipose tissue in breast cancer occurrence and development, but no comparison of adipose adjacent to breast cancer tissues and adipose adjacent to normal breast tissues has been reported. Methods: Single-nucleus RNA sequencing (snRNA-seq) was used to analyze cancer-adjacent and normal adipose tissues from the same breast cancer patient to characterize heterogeneity. SnRNA-seq was performed on 54513 cells from six samples of normal breast adipose tissue (N) distant from the tumor and tumor-adjacent adipose tissue (T) from the three patients (all surgically resected). Results and discussion: Significant diversity was detected in cell subgroups, differentiation status and, gene expression profiles. Breast cancer induces inflammatory gene profiles in most adipose cell types, such as macrophages, endothelial cells, and adipocytes. Furthermore, breast cancer decreased lipid uptake and the lipolytic phenotype and caused a switch to lipid biosynthesis and an inflammatory state in adipocytes. The in vivo trajectory of adipogenesis revealed distinct transcriptional stages. Breast cancer induced reprogramming across many cell types in breast cancer adipose tissues. Cellular remodeling was investigated by alterations in cell proportions, transcriptional profiles and cell-cell interactions. Breast cancer biology and novel biomarkers and therapy targets may be exposed.

Macrocyclic Engineering of Thermally Activated Delayed Fluorescent Emitters for High-Efficiency Organic Light-Emitting Diodes.

Several thermally activated delayed fluorescence (TADF) materials have been studied and developed to realize high-performance organic light-emitting diodes (OLEDs). However, TADF macrocycles have not been sufficiently investigated owing to the synthetic challenges, resulting in limited exploration of their luminescent properties and the corresponding highly efficient OLEDs. In this study, a series of TADF macrocycles is synthesized using a modularly tunable strategy by introducing xanthones as acceptors and phenylamine derivatives as donors. A detailed analysis of their photophysical properties combined with fragment molecules reveals characteristics of high-performance macrocycles. The results indicate that: a) the ideal structure decreases the energy loss, which in turn reduces the non-radiative transitions; b) reasonable building blocks increase the oscillator strength providing a higher radiation transition rate; c) the horizontal dipole orientation (Θ) of the extended macrocyclic emitters is increased. Owing to the high photoluminescence quantum yields of ≈100% and 92% and excellent Θ of 80 and 79% for macrocycles MC-X and MC-XT in 5 wt% doped films, the corresponding devices exhibit record-high external quantum efficiencies of 31.6% and 26.9%, respectively, in the field of TADF macrocycles.

Y-Shaped D-A Type Thioxanthone Derivatives: Mechano-Induced Thermally Activated Delayed Fluorescence and High-Contrast Mechano-Responsive Luminescence.

High-contrast mechano-responsive luminescence (MRL) materials with mechano-induced emission enhancement properties are fascinating candidates but few, for applications in rewritable media and recording devices. Here, an interesting design strategy of "Y-shape" donor-acceptor (D-A) type molecules for high-contrast MRL materials was presented, based on substituted diphenylamine donor and planar acceptor. Interestingly, their D-A torsion angles are small in crystals but increased after ground, resulted in planar and twist intramolecular charge transfer (PICT and TICT) states, respectively. Therefore, high-contrast MRL switching between weak blue (450 nm) fluorescence and bright yellow (552 nm) thermally activated delayed fluorescence (TADF) can be achieved for compound TXDO (4,4'-dimethoxydiphenylamine donor), which photoluminescence quantum yield increased from 2.8 % to 54.7 % after ground. Most importantly, the two independent D-A conjugation dihedral angles are actually independent in the "Y-shape" molecules. Especially for compound TXDT (4,4'-di-tert-butyldiphenylamine donor), its crystal exhibited both PICT and TICT processes inside, resulted from the different dihedral angles of 11.8° and 35.5°, respectively. The TXDT crystal thus showed dual-peak emission, including both TICT fluorescence and PICT room-temperature phosphorescence. Therefore, this strategy of "Y-shape" D-A type molecules provide a new approach to design advanced luminescent materials with mechano-induced TADF feature, for high-contrast MRL and single-component white luminescence.

Photoinduced Radical Persistent Luminescence in Semialiphatic Polyimide System with Temperature and Humidity Resistance.

Organic persistent luminescence (pL) systems with photoresponsive dynamic features have valuable applications in the fields of data encryption, anticounterfeiting, and bioimaging. Photoinduced radical luminescent materials have a unique luminous mechanism with the potential to achieve dynamic pL. It is extremely challenging to obtain radical pL under ambient conditions; on account of it, it is unstable in air. Herein, a new semialiphatic polyimide-based polymer (A0) is developed, which can achieve dynamic pL through reversible conversion of radical under photoexcitation. A "joint-donor-spacer-acceptor" molecular design strategy is applied to effectively modulate the intramolecular charge-transfer and charge-transfer complex interactions, resulting in effective protection of the radical generated under photoirradiation. Meanwhile, polyimide-based polymers of A1-A4 are obtained by doping different amine-containing fluorescent dyes to modulate the dynamic afterglow color from green to red via the triplet to singlet Förster resonance energy-transfer pathway. Notably, benefiting from the structural characteristics of the polyimide-based polymer, A0-A4 have excellent processability, thermal stability, and mechanical properties and can be applied directly in extreme environments such as high temperatures and humidity.

A biophotonic device based on a conjugated polymer and a macrophage-laden hydrogel for triggering immunotherapy.

A biophotonic device is fabricated by a 3D printing technique for tumor immunotherapy utilizing a flexible organic light-emitting diode (OLED) with deep blue emission and a gelatin-alginate hydrogel that contains a poly(phenylene vinylene) (PPV) derivative and live immune cells of macrophages (M0-RAW264.7). PPV is excited by the OLED to generate reactive oxygen species (ROS), enabling the macrophages to polarize to the M1 phenotype and secrete cytotoxic cytokines to induce the apoptosis of tumor cells. This strategy provides a new method for fabricating cell-involved biophotonic devices for immunotherapy.