Algorithm for optimized mRNA design improves stability and immunogenicity.

Messenger RNA (mRNA) vaccines are being used to combat the spread of COVID-19 (refs. 1-3), but they still exhibit critical limitations caused by mRNA instability and degradation, which are major obstacles for the storage, distribution and efficacy of the vaccine products4. Increasing secondary structure lengthens mRNA half-life, which, together with optimal codons, improves protein expression5. Therefore, a principled mRNA design algorithm must optimize both structural stability and codon usage. However, owing to synonymous codons, the mRNA design space is prohibitively large-for example, there are around 2.4 × 10632 candidate mRNA sequences for the SARS-CoV-2 spike protein. This poses insurmountable computational challenges. Here we provide a simple and unexpected solution using the classical concept of lattice parsing in computational linguistics, where finding the optimal mRNA sequence is analogous to identifying the most likely sentence among similar-sounding alternatives6. Our algorithm LinearDesign finds an optimal mRNA design for the spike protein in just 11 minutes, and can concurrently optimize stability and codon usage. LinearDesign substantially improves mRNA half-life and protein expression, and profoundly increases antibody titre by up to 128 times in mice compared to the codon-optimization benchmark on mRNA vaccines for COVID-19 and varicella-zoster virus. This result reveals the great potential of principled mRNA design and enables the exploration of previously unreachable but highly stable and efficient designs. Our work is a timely tool for vaccines and other mRNA-based medicines encoding therapeutic proteins such as monoclonal antibodies and anti-cancer drugs7,8.

Narrowband TADF emitters with high utilization of triplet excitons: theoretical insights and molecular design.

Narrowband emitters with thermally activated delayed fluorescence (TADF) features, known as multi-resonant TADF (MR-TADF) emitters, are drawing increasing research interest owing to their properties of high efficiency and excellent color purity. However, MR-TADF-based devices often face serious efficiency roll-off at high luminance intensity, which could be attributed to undesired triplet-triplet annihilation (TTA) caused by the structural planarity and relatively small reverse intersystem crossing rate constants (krisc) of MR-TADF emitters. Herein, combining a sp3-C inserted strategy to suppress harmful bimolecular interactions and chalcogens to improve the krisc, a series of asymmetric narrowband emitters, namely, DMAC-O, DMAC-S, and DMAC-Se, have been theoretically designed to break the slow rate-limiting step of krisc of experimental BN-DMAC. For comparison, both O and Se atoms were doped into the MR skeleton to substitute two sp3-inserted units, yielding BN-O-Se. The combination of TD-DFT and the wavefunction-based STEOM-DLPNO-CCSD approach exhibits that those asymmetric molecules are promising for simultaneously exhibiting narrow emission spectral full-width at half-maximums (FWHMs) and high luminous efficiencies. The contributions of chalcogens to hole distributions result in red-shifted fluorescent peaks, and the asymmetric strategy also helps with twisted molecular configuration, which is beneficial for suppressing unfavorable TTA. Furthermore, the incorporation of chalcogens is sufficient to promote the intersystem crossing and reverse intersystem crossing channels of asymmetric emitters. More importantly, the doped heavy Se atom results in a significantly increased krisc of 2.32 × 106 s-1 for DMAC-Se, which is more than 200 times larger than 1.09 × 104 s-1 of pristine BN-DMAC. These results suggest that the combination of the heavy Se atom and an sp3-inserted unit is a feasible strategy for achieving poor planarity and significantly enhancing krisc, which will help in harvesting triplet excitons, thereby inhibiting efficiency roll-off in corresponding narrowband devices.

Narrowband emission from fully-bridged triphenylamine derivatives: insights into effects of structure modification and pressure.

Triphenylamine derivatives with narrowband emission have attracted growing attention in purely organic thermally-activated fluorescence (TADF) materials owing to their enhanced color purity and flexible molecular design strategy. Combined time-dependent density functional theory (TD-DFT) and ONIOM (QM/MM) calculations indicate that the excellent planarity of the experimentally developed DQAO could result in gradually decreased intermolecular interactions in the aggregated state at ambient pressure and upon compression, which is unfavorable for suppressing structural relaxation and achieving narrowband emission in its non-doped practical application. Therefore, three structure-modified derivatives, DQAO-Cb, DQAO-Ph, and DQAO-PhCb, were theoretically designed by introducing the spherical o-carborane and dangling phenyl units positioned para to the N atom of the DQAO to provide additional geometrical distortion and steric hindrance. The explorations on the reported DQAO, OQAO, and SQAO found that small structural relaxations, suppressed low-frequency vibrations, and noticeable short-range charge-transfer (SR-CT) natures of DQAO and OQAO are responsible for their much narrower emission spectral full-width at half-maxima (FWHMs) compared to that of SQAO. Introducing the o-carborane unit directly at the para position of the N atom could result in additional scissoring and stretching vibrations of the corresponding DQAO-Cb while the presence of the phenyl unit in DQAO-Ph is beneficial for suppressing the high-frequency vibrations of the pristine DQAO. More importantly, the bridged phenyl unit incorporated in DQAO-PhCb is of particular importance to inhibit the undesired low-frequency scissoring and high-frequency stretching vibrations of the o-carborane unit, which is crucial to reduce the reorganization energy of DQAO-PhCb and achieve narrowband emission. Also, the phenyl unit in DQAO-Ph and DQAO-PhCb helps to shorten charge transfer distances and improve ISC and RISC processes. Since the o-carborane unit is an adopted building block to achieve piezochromic behaviors, the theoretically structure-modified DQAO-PhCb is expected to exhibit narrowband emission, TADF, and piezochromic features all together. Our findings will hopefully provide ideas for designing triphenylamine-based TADF emitters with narrowband emission and piezochromic behaviors.

Unusual Thermal Quenching of Photoluminescence from an Organic-Inorganic Hybrid [MnBr4 ]2- -based Halide Mediated by Crystalline-Crystalline Phase Transition.

The ability to generate and manipulate photoluminescence (PL) behavior has been of primary importance for applications in information security. Excavating novel optical effects to create more possibilities for information encoding has become a continuous challenge. Herein, we present an unprecedented PL temporary quenching that highly couples with thermodynamic phase transition in a hybrid crystal (DMML)2 MnBr4 (DMML=N,N-dimethylmorpholinium). Such unusual PL behavior originates from the anomalous variation of [MnBr4 ]2- tetrahedrons that leads to non-radiation recombination near the phase transition temperature of 340 K. Remarkably, the suitable detectable temperature, narrow response window, high sensitivity, and good cyclability of this PL temporary quenching will endow encryption applications with high concealment, operational flexibility, durability, and commercial popularization. Profited from these attributes, a fire-new optical encryption model is devised to demonstrate high confidential information security. This unprecedented optical effect would provide new insights and paradigms for the development of luminescent materials to enlighten future information encryption.

Organic-Inorganic Hybrid Ferroelectric and Antiferroelectric with Afterglow Emission.

Luminescent ferroelectrics are holding exciting prospect for integrated photoelectronic devices due to potential light-polarization interactions at electron scale. Integrating ferroelectricity and long-lived afterglow emission in a single material would offer new possibilities for fundamental research and applications, however, related reports have been a blank to date. For the first time, we here achieved the combination of notable ferroelectricity and afterglow emission in an organic-inorganic hybrid material. Remarkably, the presented (4-methylpiperidium)CdCl3 also shows noticeable antiferroelectric behavior. The implementation of cationic customization and halogen engineering not only enables a dramatic enhancement of Curie temperature of 114.4 K but also brings a record longest emission lifetime up to 117.11 ms under ambient conditions, realizing a leapfrog improvement of at least two orders of magnitude compared to reported hybrid ferroelectrics so far. This finding would herald the emergence of novel application potential, such as multi-level density data storage or multifunctional sensors, towards the future integrated optoelectronic devices with multitasking capabilities.

ATP-P2X7R-mediated microglia senescence aggravates retinal ganglion cell injury in chronic ocular hypertension.

BACKGROUND: Dysfunction of microglia during aging affects normal neuronal function and results in the occurrence of neurodegenerative diseases. Retinal microglial senescence attributes to retinal ganglion cell (RGC) death in glaucoma. This study aims to examine the role of ATP-P2X7R in the mediation of microglia senescence and glaucoma progression. METHODS: Forty-eight participants were enrolled, including 24 patients with primary open-angle glaucoma (POAG) and age-related cataract (ARC) and 24 patients with ARC only. We used ARC as the inclusion criteria because of the availability of aqueous humor (AH) before phacoemulsification. AH was collected and the adenosine triphosphate (ATP) concentration was measured by ATP Assay Kit. The chronic ocular hypertension (COH) mouse model was established by microbead occlusion. Microglia were ablated by feeding PLX5622 orally. Mouse bone marrow cells (BMCs) were prepared and infused into mice through the tail vein for the restoration of microglia function. Western blotting, qPCR and ELISA were performed to analyze protein and mRNA expression in the ocular tissue, respectively. Microglial phenotype and RGC survival were assessed by immunofluorescence. The mitochondrial membrane potential was measured using a JC-1 assay kit by flow cytometry. RESULTS: ATP concentrations in the AH were increased in older adults and patients with POAG. The expression of P2X7R was upregulated in the retinal tissues of mice with glaucoma, and functional enrichment analysis showed that P2X7R was closely related to cell aging. Through in vivo and in vitro approaches, we showed that pathological activation of ATP-P2X7R induced accelerated microglial senescence through impairing PTEN-induced kinase 1 (PINK1)-mediated mitophagy, which led to RGC damage. Additionally, we found that replacement of senescent microglia in COH model of old mice with BMCs from young mice reversed RGC damage. CONCLUSION: ATP-P2X7R induces microglia senescence by inhibiting PINK1-mediated mitophagy pathway. Specific inhibition of ATP-P2X7R may be a fundamental approach for targeted therapy of RGC injury in microglial aging-related glaucoma.

Near-Infrared Piezochromism from an o-Carborane Dyad: Boron Clusters Facilitating a Wide-Range Redshift and High Sensitivity.

Piezochromic materials, which exhibit a fluorescence response with large emission spectral shifts and high sensitivity, may be useful in important applications, but there have been few reports of such organic luminophores. Herein, we report a new high-sensitivity piezochromic material based on the incorporation of an o-carborane unit, which exhibits aggregation-induced emission properties. In a high-pressure experiment, compared to carborane-free MTY, which exhibits an emission spectral shift of 75 nm and a sensitivity of 19.1 nm ⋅ GPa-1 , the o-carborane dyad MTCb shows a larger emission wavelength difference of 131 nm and a higher sensitivity of 32.8 nm ⋅ GPa-1 , demonstrating a performance that ranks among the best of organic piezochromic materials reported thus far. MTCb molecules adopt a J-aggregated pattern and have relatively loose molecular packing in the crystalline state. Interestingly, nonconjugated spherical carborane can disrupt the π-π interactions between adjacent molecules during compression, which results in excellent piezochromic performance.

Near-infrared Piezochromic Materials at High Pressure.

The study of piezochromic materials (PCMs) has become an attractive field and numerous scholars have reported various material structures and phenomena. PCMs incorporating near-infrared (NIR) emission have led to a broader range of applications due to the strong penetration and interference resistance of longer wavelength light sources. However, NIR PCMs are still rare due to difficulties in tuning molecular configuration, conformation and stacking structure. In this review, organic compounds are classified according to their types and structures, and recent advances in NIR PCMs are comprehensively summarized and described. The various factors affecting the piezochromic properties from the perspective of the compound structure are shown. The effects of pressure on the photophysical changes of different compounds are discussed. It is expected to provide ideas for subsequent NIR PCMs, from structural design to predicting their photophysical properties under pressure.

Forensic Pathological Analysis of Death Due to Pulmonary Thromboembolism: A Retrospective Study Based on 145 Cases.

ABSTRACT: Pulmonary thromboembolism (PTE) is a common cause of sudden unexpected death in forensic and clinical practice. Although the prevention of thrombosis has been paid more attention in clinical practice in recent years, the number of deaths due to PTE remains extensive. In the present study, 145 cases of fatal PTE were collected and retrospectively analyzed from 2001 to 2020 at the School of Forensic Medicine, China Medical University in Liaoning Province, northeast of China. The demographic characteristics, risk factors of PTE, origins of thrombi, and time interval from the occurrence of main risk factors to PTE were retrospectively analyzed. The 40 to 59 age group accounted for the 51.0% of the total cases. Immobilization, trauma (especially fracture of the pelvis, femur, tibia, or fibula), surgery, cesarean section, and mental disorders were the top 5 high-risk factors. Among the involved cases, 92.9% of the PTE (130/140) occurred within 60 days and peak at 8 to 15 days after the exposure of main risk factors. According to the autopsy findings, 87.6% of the thrombi blocked the bilateral pulmonary arteries at pulmonary hilus, with a maximum diameter of 1.6 cm and a maximum length of 21.9 cm, which were mainly derived from lower limb (65.5%) or pelvic veins (10.3%). Although the embolus limited the pulmonary circulation, there is no difference on the ratio of lung-to-heart weight between PTE and the disease-free accident victims. Overall, our present retrospective study provides important information for the forensic analysis on the cause of death and potential guidance on clinical prevention of PTE.

Host-Guest Doping in Flexible Organic Crystals for Room-Temperature Phosphorescence.

Organic single crystals (OSCs) with excellent flexibility and unique optical properties are of great importance due to their broad applicability in optical/optoelectronic devices and sensors. Nevertheless, fabricating flexible OSCs with room-temperature phosphorescence (RTP) remains a great challenge. Herein, we propose a host-guest doping strategy to achieve both RTP and flexibility of OSCs. The single-stranded crystal is highly bendable upon external force application and can immediately return to its original straight shape after removal of the stress, impressively emitting bright deep-red phosphorescence. The theoretical and experimental results demonstrate that the bright RTP arises from Förster resonance energy transfer (FRET) from the triphenylene molecules to the dopants. This strategy is both conceptually and synthetically simple and offers a universal approach for the preparation of flexible OSCs with RTP.

Excitation-Dependent Multicolour Luminescence of Organic Materials: Internal Mechanism and Potential Applications.

Excitation-dependent emission (Ex-de) materials have been of considerable academic interest and have potential applications in real life. Such multicolour luminescence is a characteristic exception to the ubiquitously accepted Kasha's rule. This phenomenon has been increasingly presented in some studies on different luminescence systems; however, a systematic overview of the mechanisms underlying this phenomenon is currently absent. Herein, we resolve this issue by classifying multicolour luminescence from single chromophores and dual/ternary chromophores, as well as multiple emitting species. The underlying processes are described based on electronic and/or geometrical conditions under which the phenomenon occurs. Before we present it in categories, related photophysical and photochemical foundations are introduced. This systematic overview will provide a clear approach to designing multicolour luminescence materials for special applications.

Confining isolated chromophores for highly efficient blue phosphorescence.

High-efficiency blue phosphorescence emission is essential for organic optoelectronic applications. However, synthesizing heavy-atom-free organic systems having high triplet energy levels and suppressed non-radiative transitions-key requirements for efficient blue phosphorescence-has proved difficult. Here we demonstrate a simple chemical strategy for achieving high-performance blue phosphors, based on confining isolated chromophores in ionic crystals. Formation of high-density ionic bonds between the cations of ionic crystals and the carboxylic acid groups of the chromophores leads to a segregated molecular arrangement with negligible inter-chromophore interactions. We show that tunable phosphorescence from blue to deep blue with a maximum phosphorescence efficiency of 96.5% can be achieved by varying the charged chromophores and their counterions. Moreover, these phosphorescent materials enable rapid, high-throughput data encryption, fingerprint identification and afterglow display. This work will facilitate the design of high-efficiency blue organic phosphors and extend the domain of organic phosphorescence to new applications.

Microglia-derived TNF-α mediates Müller cell activation by activating the TNFR1-NF-κB pathway.

Microglia and its interaction with Müller cells are responsible to retinal surveillance during retinal neurodegeneration, however, the role and mechanism of microglia-derived tumor necrosis factor (TNF)-α in the activation of retinal Müller cells have not been fully elucidated. In the present study, primary microglia and Müller cells were isolated from newborn Sprague-Dawley (SD) rats with purities of 88.2 ± 6.2% and 92.2 ± 2.2%, respectively. By performing immunofluorescence and Western blot analysis, we found that TNF receptor (TNFR)-1 and TNFR2 were expressed in Müller cells. After co-cultured with microglia-conditioned medium (MCM), the elevated mRNA levels of glial fibrillary acidic protein (GFAP), proinflammatory factors (TNF-α, IL-1ß, CXCL-1, CSF-1, NOS2, COX2) and decreased CNTF mRNA levels were found in Müller cells. However, pretreatment with R-7050 (a TNF-α receptor inhibitor) or anti-TNFR1 significantly abrogated the changes. Simultaneously, pretreatment with anti-TNFR2 slightly inhibited the expression of GFAP in MCM-incubated Müller cells. Meanwhile, anti-TNFR1 treatment reversed the increased expression of CSF-1 and IL-1ß induced by TNF-α. Compared to the control groups, the phosphorylation of NF-κB P65, MAPK P38 and ERK1/2 in TNF-α-treated Müller cells was significantly increased. Nevertheless, pretreatment with anti-TNFR1 inhibited the phosphorylation of NF-κB P65 and MAPK p38, especially NF-κB P65. Additionally, pretreatment with Bay117082 (an NF-κB inhibitor) also significantly inhibited NF-κB P65 phosphorylation and GFAP expression. Moreover, anti-TNFR1 and Bay117082 treatment reduced NF-κB P65 phosphorylation of Müller cells induced by MCM. These results suggested that microglia-derived TNF-α served as a vital role in regulating Müller cells activation during retinal neurodegeneration.

A Water-Soluble Epoxy-Based Green Crosslinking System for Stabilizing PVA Nanofibers.

With the ever-growing concern about environmental conservation, green production and water-based nanofibers have attracted more and more interest from both academic and industrial fields; nevertheless, the stabilization process of water-based nanofibers is primarily relying on the application of organic solvent-based crosslinking agents. In this work, we develop a green approach to fabricate water-resistant polyvinyl alcohol (PVA) nanofibers by using a water-based epoxy compound, N1, N6-bis(oxiran-2-ylmethyl) hexane-1,6-diamine (EH), as the crosslinker. This EH/sodium carbonate/sodium bicarbonate (CBS) solution system can break down large aggregates of PVA molecules into small ones and promote the uniform distribution of EH in the solution, resulting in the improved stability of crosslinked PVA nanofibers. We firstly report that the uniform dispersion of crosslinking agents in the electrospinning solution plays a vital role in improving the stability of spinning solutions and the water resistance of crosslinked PVA nanofibers by comparing crosslinking performances between water-based epoxy and conventional water-based blocked isocyanate (BI). This work could open up a novel strategy and green approach for the stabilization of water-based nanofibers.

Piezochromic Tetracoordinate Boron Complex: Blue-Shifted and Enhanced Luminescence.

Achieving blueshifted and enhanced emission from purely organic luminophors remains a major challenge. Herein, we report a tetracoordinate boron complex with polymorphism (Y-phase and O-phase)-dependent luminescence. Impressively, the Y-phase crystals exhibited rare piezochromic luminescent properties such as pressure-induced blue-shifted and enhanced emission. The results of theoretical and experimental tests demonstrated that this phenomenon results from the cooperative effect between the restriction of intramolecular motions and alterable charge transfer (CT) behavior during compression. This work provides an ideal model to investigate the optoelectronic properties of boron complexes. Importantly, manipulating the CT behavior through the electrophilicity of boron atoms may become a new principle for the design of piezochromic materials with blueshifted and enhanced emission.

Multicolour Fluorescence Based on Excitation-Dependent Electron Transfer Processes in o-Carborane Dyads.

Organic materials with excitation wavelength-dependent (Ex-de) emission are highly attractive for anticounterfeiting, optoelectronics and bioassay applications; however, the realization of Ex-de fluorescence, independent of aggregation states, remains a challenge. We herein report a photoinduced electron transfer (PeT) strategy to design Ex-de fluorescence materials by manipulating the relaxation pathways of multiple excited states. As expected, the o-carborane dyad presents a clear Ex-de fluorescence colour in the aggregated states, resulting from the tunable relative intensity of the dual-fluorescence spectra. Taking TP[1]B as an example, the amorphous powders emitted bright blue-violet, white and yellow colours under 390 nm, 365 nm and 254 nm UV illumination, respectively. Importantly, multicolour, flexible and transparent films as well as an anticounterfeiting application using this o-carborane dyad are demonstrated.

Blood biomarkers of bone metastasis in digestive tract malignant tumors.

Aim: To evaluate the role of clinical features and blood markers in patients with malignant digestive tract tumors bone metastasis. Materials & methods: A total of 267 patients were included in this trial. Age, gender, primary tumor site, metastatic sites, T/N stage, high-density lipoprotein, low-density lipoprotein, total cholesterol, triglycerides, alkaline phosphatase, LDH, Ca levels, platelet, neutrophils to absolute value of lymphocytes (NLR), ratio of platelets to absolute values of lymphocytes (PLR) were analyzed. Results: T stage, lymph node metastasis, N stage and liver and lung metastasis were independent risk factors. LDH + alkaline phosphatase + NLR + PLR and LDH + NLR, respectively have higher predictive value for bone metastasis compared with patients with early-stage malignant digestive tract tumor and patients with advanced malignant digestive tract tumor without bone metastasis. Conclusion: Some clinical features or blood markers have the potential to detect bone metastasis early to avoid skeletal complications.

Associations of plasma 8-iso-prostaglandin F2αlevels with fasting blood glucose (FBG) and intra-abdominal fat (IAF) area in various Glycometabolism populations.

BACKGROUND: This study aimed to investigate the differences in oxidative stress (OS) levels represented by 8-iso-prostaglandin F2α (8-iso-PGF2α) and analyze its correlation with the intra-abdominal fat (IAF) area and the glycolipid index. METHODS: We recruited a total of 160 eligible subjects. According to the blood glucose levels and the T2DM duration, subjects were divided into three groups: Type 2 Diabetes (T2DM) group, Prediabetic group, and Normal glucose-tolerance (NC) group, containing 66, 41, 53 patients, respectively. T2DM groups were additionally divided into a new-onset T2DM group including 29 patients and a non-new-onset T2DM group including 37 patients. General clinical data and biochemical indicators were collected. Intra-abdominal fat (IAF) was measured by MRI. 8-iso-PGF2α was measured by ELISA. RESULTS: Compared with the NC group, levels of systolic blood pressure (SBP), waist-to-hip ratio (WHR), FBG, 2 h postprandial glycemia(2hPG), 2 h insulin (2 h INS), IAF area, HOMA-IR, and 8-iso-PGF2α increased, and high-density lipoprotein cholesterol (HDL-C) decreased in T2DM groups and Prediabetic group (P < 0.05). The 2 h INS level was the highest in the Prediabetic group; 2hPG, and IAF area were the highest in the new-onset T2DM group; WHR, FBG, HOMA-IR and 8-iso-PGF2α were the highest in the non-new-onset T2DM group. Multiple stepwise regression analysis identified IAF area and FBG as the strongest and independent determinant of 8-iso-PGF2α (P < 0.01). CONCLUSIONS: In various glycometabolism populations, 8-iso-PGF2α is significantly correlated with FBG and IAF, this suggests that high blood glucose and abdominal obesity can increase the damage related to the OS in vivo.

Associations between health indicators and sleep duration of American adults: NHANES 2011-16.

BACKGROUND: This study aimed to investigate associations between health indicators and sleep duration in the general population. METHODS: This cross-sectional data from the National Health and Nutrition Examination Survey. Self-reported sleep duration was classified into short sleep (<7 h/day), regular sleep (7-8 h/day) and long sleep duration (>8 h/day). Health indicators included lifestyle indicators (smoking, alcohol use and physical inactivity), general health indicators (waist circumference and self-reported health condition) and chronic conditions [overweight/obesity, hypertension, diabetes, high cholesterol, chronic low back pain (CLBP) and oral health problems]. A series of multinomial logistic regression analysis were performed, controlling for confounders (age, sex, marital status, ethnic background, education level and poverty-to-income ratio). RESULTS: Data of 12 835 participants were analyzed. The mean (SD) age of participants was 50.0 (±17.4) years, and 50.6% were women. After adjusting for all health indicators, current smoking (OR: 1.37; 95% CI: 1.17-1.61), a poor (OR: 1.52; 95% CI: 1.23-1.88) health condition, CLBP (OR: 1.40; 95% CI: 1.16-1.69) and oral health problems (OR: 1.28; 95% CI: 1.10-1.49) were associated with short sleep duration. No independent association with long sleep duration was observed in this study. CONCLUSIONS: The results confirm that lifestyle indicators (current smoking and physical inactivity), general health indicators (self-reported health condition) and presence of some chronic conditions (CLBP and oral health problems) are associated with short sleep duration. The results did not confirm that any health indicator was associated with long sleep duration.

Design of Persistent and Stable Porous Radical Polymers by Electronic Isolation Strategy.

Conjugated organic radical polymers with stable radical features are difficult to design because the π conjugation in the polymer backbones makes the radicals readily delocalize and tend to undergo covalent bonding processes. In this work, we report an electronic isolation strategy to design stable porous radical polymers by homocoupling reaction from a meta-position active monomer. The meta linkage ensures less conjugation in the polymer skeletons, localizes the resonant radicals, and prevents them from recombination. The resulting porous radical polymer exhibits exceptional radical characters with ultralow band gap of 0.68 eV, strong yet extended UV/Vis-NIR absorption up to 1800 nm, and high spin density. The above features make the polymer very promising in the photothermal conversion with record-high photothermal temperature increment of ≈∼240 °C and striking solar-driven water evaporation efficiency of 96.8 %. Our results demonstrate the feasibility of electronic isolation of radicals for producing outstanding photothermal materials.