Diels-Alder Reaction Mechanisms of La@C60 and Gd@C60 Studied Using Density Functional Theory.

Encapsulation of transition metals represents a crucial method for modifying the electronic structure and regulating the reactivity of fullerene, thereby expanding its applications. Herein, we present calculations with density functional theory methods to investigate the mechanisms of the Diels-Alder (DA) reactions of cyclopentadiene and La@C60 or Gd@C60 as well as their tricationic derivatives. Our findings indicate that the encapsulation of La and Gd into the C60 cage is thermodynamically favorable. The DA reactions are favored by the presence of La and Gd, with lower barriers, though the regioselectivity, favoring 6-6 bonds in the fullerene, is not affected. The effect of external electric fields has been also considered.

JAM3 promotes cervical cancer metastasis by activating the HIF-1α/VEGFA pathway.

Cervical cancer is the fourth most common cancer and the leading cause of mortality among women worldwide. Tumor metastasis is an important cause of poor prognosis. Determining the exact mechanisms of metastasis and potential targeted therapies is urgently needed. Junctional adhesion molecule 3 (JAM3) is an important member of the TJ tight junction (TJ) family, and its biological function in cervical cancer needs to be further clarified. We found that JAM3 was highly expressed in cervical cancer patients with lymph node metastasis and that high expression of JAM3 promoted cervical cancer cell metastasis both in vitro and in vivo. In addition, overexpression of JAM3 induces epithelial-mesenchymal transition (EMT). Moreover, silencing JAM3 suppressed cervical cancer cell migration and invasion in vitro. Finally, JAM3 overexpression activated the HIF-1α/VEGFA pathway. In conclusion, our results suggested that JAM3 promotes cervical cancer cell migration and invasion by activating the HIF-1α/VEGFA pathway. JAM3 may be a promising biomarker and effective therapeutic target for cervical cancer.

The role of walnut bZIP genes in explant browning.

BACKGROUND: Basic leucine zipper (bZIP) proteins are important transcription factors in plants. To study the role of bZIP transcription factors in walnut explant browning, this study used bioinformatics software to analyze walnut bZIP gene family members, along with their transcript levels in different walnut tissues, to evaluate the transcriptional expression of this gene family during the primary culture of walnut explants and to reveal the mechanism of action of walnut bZIP genes in walnut explant browning. RESULTS: The results identified 65 JrbZIP genes in the walnut genome, which were divided into 8 subfamilies and distributed on 16 chromosomes. The results of transcriptome data analysis showed that there were significant differences in the expression of four genes, namely, JrbZIP55, JrbZIP70, JrbZIP72, and JrbZIP88, under both vermiculite and agar culture conditions. There were multiple hormone (salicylic acid, abscisic acid, auxin, and gibberellin) signaling and regulatory elements that are responsive to stress (low temperature, stress, and defense) located in the promoter regions of JrbZIP55, JrbZIP70, JrbZIP72, and JrbZIP88. The walnut JrbZIP55 protein and Arabidopsis bZIP42 protein are highly homologous, and the proteins interacting with Arabidopsis bZIP42 include the AT2G19940 oxidoreductases, which act on aldehyde or oxygen-containing donors. CONCLUSION: It is speculated that JrbZIP55 may participate in the regulation of browning in walnut explants.

Additive-Enhanced Crystallization of Inorganic Perovskite Single Crystals for High-Sensitivity X-Ray Detection.

Inorganic cesium lead halide perovskite single crystals are particularly intriguing to ionizing radiation detection by virtue of their material stability and high attenuation coefficients. However, the growth of high-quality inorganic perovskite single crystals remains challenging, mainly due to the limited solubility. In this work, an additive-enhanced crystallization method is proposed for cesium lead perovskites. The additive can remarkably increase the solubility of cesium bromide in dimethyl sulfoxide (DMSO) forming a balanced stoichiometric precursor solution, which prevents the formation of impurity phases. In addition, the additives would react with DMSO generating glyoxylic acid (GLA) via nucleophilic substitution and Kornblum oxidation reactions. The GLA can form stable PbBr2 -DMSO-GLA complexes, which enables better crystallinity, uniformity and much longer carrier lifetimes for the grown single crystals. The X-ray detectors using the additive-enhanced crystals exhibit an ultra-high sensitivity of 3.0 × 104  µC Gyair -1 cm-2 which is more than two orders of magnitude higher than that for the control devices.

HMGB3 promotes the malignant phenotypes and stemness of epithelial ovarian cancer through the MAPK/ERK signaling pathway.

BACKGROUND: Ovarian cancer, particularly epithelial ovarian cancer (EOC), is the leading cause of cancer-related mortality among women. Our previous study revealed that high HMGB3 levels are associated with poor prognosis and lymph node metastasis in patients with high-grade serous ovarian carcinoma; however, the role of HMGB3 in EOC proliferation and metastasis remains unknown. METHODS: MTT, clonogenic, and EdU assays were used to assess cell proliferation. Transwell assays were performed to detect cell migration and invasion. Signaling pathways involved in HMGB3 function were identified by RNA sequencing (RNA-seq). MAPK/ERK signaling pathway protein levels were evaluated by western blot. RESULTS: HMGB3 knockdown inhibited ovarian cancer cell proliferation and metastasis, whereas HMGB3 overexpression facilitated these processes. RNA-seq showed that HMGB3 participates in regulating stem cell pluripotency and the MAPK signaling pathway. We further proved that HMGB3 promotes ovarian cancer stemness, proliferation, and metastasis through activating the MAPK/ERK signaling pathway. In addition, we demonstrated that HMGB3 promotes tumor growth in a xenograft model via MAPK/ERK signaling. CONCLUSIONS: HMGB3 promotes ovarian cancer malignant phenotypes and stemness through the MAPK/ERK signaling pathway. Targeting HMGB3 is a promising strategy for ovarian cancer treatment that may improve the prognosis of women with this disease. Video Abstract.

Removal of Phenols by Highly Active Periodate on Carbon Nanotubes: A Mechanistic Investigation.

Carbon nanotubes (CNTs) and their derivatives have been widely exploited to activate various oxidants for environmental remediation. However, the intrinsic mechanism of CNTs-driven periodate (PI) activation remains ambiguous, which significantly impedes their scientific progress toward practical application. Here, we found that CNTs can strongly boost PI activation for the oxidation of various phenols. Reactive oxygen species analysis, in situ Raman characterization, galvanic oxidation process experiments, and electrochemical tests revealed that CNTs could activate PI to form high-potential metastable intermediates (CNTs-PI*) rather than produce free radicals and 1O2, thereby facilitating direct electron transfer from the pollutants to PI. Additionally, we analyzed quantitative structure-activity relationships between rate constants of phenols oxidation and double descriptors (e.g., Hammett constants and logarithm of the octanol-water partition coefficient). The adsorption of phenols on CNT surfaces and their electronic properties are critical factors affecting the oxidation process. Besides, in the CNTs/PI system, phenol adsorbed the CNT surfaces was oxidized by the CNTs-PI* complexes, and products were mainly generated via the coupling reaction of phenoxyl radical. Most of the products adsorbed and accumulated on the CNT surfaces realized phenol removal from the bulk solution. Such a unique non-mineralization removal process achieved an extremely high apparent electron utilization efficiency of 378%. The activity evaluation and theoretical calculations of CNT derivatives confirmed that the carbonyl/ketonic functional groups and double-vacancy defects of the CNTs were the primary active sites, where high-oxidation-potential CNTs-PI* were formed. Further, the PI species could achieve a stoichiometric decomposition into iodate, a safe sink of iodine species, without the generation of typical iodinated byproducts. Our discovery provides new mechanistic insight into CNTs-driven PI activation for the green future of environmental remediation.

Redox-Active Polymers as Robust Electron-Shuttle Co-Catalysts for Fast Fe3+/Fe2+ Circulation and Green Fenton Oxidation.

Accelerating the rate-limiting Fe3+/Fe2+ circulation in Fenton reactions through the addition of reducing agents (or co-catalysts) stands out as one of the most promising technologies for rapid water decontamination. However, conventional reducing agents such as hydroxylamine and metal sulfides are greatly restricted by three intractable challenges: (1) self-quenching effects, (2) heavy metal dissolution, and (3) irreversible capacity decline. To this end, we, for the first time, introduced redox-active polymers as electron shuttles to expedite the Fe3+/Fe2+ cycle and promote H2O2 activation. The reduction of Fe3+ mainly took place at active N-H or O-H bonds through a proton-coupled electron transfer process. As electron carriers, H atoms at the solid phase could effectively inhibit radical quenching, avoid metal dissolution, and maintain long-term reducing capacity via facile regeneration. Experimental and density functional theory (DFT) calculation results indicated that the activity of different polymers shows a volcano curve trend as a function of the energy barrier, highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap, and vertical ionization potential. Thanks to the appropriate redox ability, polyaniline outperforms other redox-active polymers (e.g., poypyrrole, hydroquinone resin, poly(2,6-diaminopyridine), and hexaazatrinaphthalene framework) with a highest iron reduction capacity up to 5.5 mmol/g, which corresponds to the state transformation from leucoemeraldine to emeraldine. Moreover, the proposed system exhibited high pollutant removal efficiency in a flow-through reactor for 8000 bed volumes without an obvious decline in performance. Overall, this work established a green and sustainable oxidation system, which offers great potential for practical organic wastewater remediation.

Par3/integrin ß1 regulates embryo adhesion via changing endometrial luminal epithelium polarity†.

The objective is to investigate the pathophysiological significance of Par3 and integrin ß1 with regard to the functionality of the endometrial luminal epithelium (LE). Design: laboratory study; setting: university research laboratory. Analysis involved endometrial aspirates and endometrial adenocarcinoma cells (HEC-1A) and endometrial carcinoma cells (RL95-2). We first examined the expression and localization of Par3 and integrin ß1 in HEC-1A cells and RL95-2 cells. Then we knocked down Par3 and integrin ß1 in HEC-1A cells and RL95-2 cells, respectively, and found that Par3/integrin ß1 affected embryo adhesion by regulating the intercellular tight junctions' (TJs') structure and thus the polarity of the endometrial LE. These findings were also confirmed in the endometrium specimens from human and mice. The main outcome measures were the expression and localization of Par3 and integrin ß1 in the endometrial epithelial cell lines and endometrium specimens and the regulations of Par3 and integrin ß1 on TJs, polarity, and embryo adhesion. Following the knockdown of Par3 in HEC-1A cells, there was a reduction in the complexity of the TJs and cell polarity, and the adhered blastocysts number was significantly increased. However, the reduction of integrin ß1 in RL95-2 cells resulted in effects that directly opposed those following the knockdown of Par3 in HEC-1A cells. Estrogen and progesterone reduced the expression of Par3 and promoted the expression of integrin ß1 in HEC-1A cells. Par3/integrin ß1 regulates embryo adhesion by regulating intercellular TJs' structure and polarity of endometrial LE under the action of ovarian hormones.

Insights into the Electron-Transfer Mechanism of Permanganate Activation by Graphite for Enhanced Oxidation of Sulfamethoxazole.

Many reagents as electron sacrificers have been recently investigated to induce decomposition of permanganate (KMnO4) to produce highly reactive intermediate Mn species toward oxidation of organic contaminants; however, this strategy meanwhile causes low KMnO4 utilization efficiency. This study surprisingly found that graphite can mediate direct electron transfer from organics (e.g., sulfamethoxazole (SMX)) to KMnO4, resulting in high KMnO4 utilization efficiency, rather than reductive sites of graphite-induced conversion of KMnO4 to highly reactive intermediate Mn species. The galvanic oxidation process (GOP) and comparative experiments of different organic contaminants prove that the KMnO4/graphite system mainly extracts electrons from organic contaminants via a one-electron pathway instead of a two-electron pathway. More importantly, the KMnO4/graphite system has superior reusability, graphite can keep a long-lasting reactivity, and the KMnO4 utilization efficiency elevates significantly after each cycle of graphite. The transformation of SMX in the KMnO4/graphite system mainly includes self-coupling, hydroxylation, oxidation, and hydrolytic reaction. The work will improve insights into the electron-transfer mechanism and unveil the advantages of efficient KMnO4 utilization in the KMnO4-based technologies in environmental remediation.

Tim-4 Inhibits NLRP3 Inflammasome via the LKB1/AMPKα Pathway in Macrophages.

Nonalcoholic fatty liver disease (NAFLD), characterized by excessive inflammation and lipid deposition, is one of the most common metabolic liver diseases. The expression of NLRP3 inflammasome in macrophages is significantly increased in NAFLD, and its activation aggravates NAFLD greatly. Tim-4, as the phosphatidylserine (PS) receptor, is expressed highly in macrophages, and macrophage Tim-4 inhibits inflammation under various conditions of immune activation. However, the precise role of Tim-4 in NLRP3 inflammasome regulation and NAFLD pathogenesis remains completely unknown. Using NAFLD mice models, we confirmed that the expression of Tim-4 was increased in liver tissues by Western blot, real-time PCR, immunohistochemistry, and immunofluorescence, especially higher expression in liver macrophages, and Tim-4 knockout mice displayed more severe liver inflammation and hepatic steatosis than controls in NAFLD mice model. In vitro, we found that Tim-4 could inhibit NLRP3 inflammasome activation, and the inhibition was dependent on PS binding domain in the IgV domain. Mechanistically, Tim-4 induced the degradation of NLRP3 inflammasome components through activating AMPKα-mediated autophagy. Specifically, Tim-4 promoted AMPKα phosphorylation by interacting with LKB1 and AMPKα. In addition, PS binding motif was responsible for Tim-4-mediated AMPKα and LKB1 interaction. In conclusion, NAFLD microenvironments upregulate Tim-4 expression in macrophages, and elevated Tim-4, in turn, suppresses NLRP3 inflammasome activation by activating LKB1/AMPKα-mediated autophagy, thereby ameliorating the release of IL-1ß and IL-18. Collectively, this study unveils the novel function of Tim-4 in suppressing NLRP3 inflammasome, which would shed new lights on intervention of NAFLD or inflammatory liver diseases by targeting Tim-4.

mInscuteable regulates meiotic spindle organization during mouse oocyte meiotic maturation.

Establishment of cellular polarity is one of the key events during oocyte maturation. Inscuteable (Insc) has been identified as a key regulator of cell polarity during asymmetric division in Drosophila. However, the function of its evolutionarily conserved mammalian homologue, mInscuteable (mInsc), in mouse meiotic maturation is not clear. In this study, we investigated the roles of mInsc in mouse oocyte maturation. mInsc was detected at all stages of oocyte maturation. The protein level of mInsc was slightly higher at the germinal vesicle breakdown (GVBD) stage and remained constant during mouse oocyte maturation. The subcellular localization of mInsc overlapped with spindle microtubules. Disruption of microtubules and microfilaments caused changes in the localization of mInsc. Depletion or overexpression of mInsc significantly decreased the maturation rates of mouse oocytes. Depletion of mInsc significantly affected asymmetric division, spindle assembly, alignments of chromosomes and actin cap formation. Taken together, our results demonstrated that mInsc regulates meiotic spindle organization during mouse meiotic maturation.

Interlayer Hydrogen-Bonded Metal Porphyrin Frameworks/MXene Hybrid Film with High Capacitance for Flexible All-Solid-State Supercapacitors.

2D metal-porphyrin frameworks (MPFs) are attractive for advanced energy storage devices. However, the inferior conductivity and low structural stability of MPFs seriously limit their application as flexible free-standing electrodes with high performance. Here, for the first time, an interlayer hydrogen-bonded MXene/MPFs film is proposed to overcome these disadvantages by intercalation of highly conductive MXene nanosheets into MPFs nanosheets via a vacuum-assisted filtration technology. The alternant insertion of MXene and MPFs affords 3D interconnected "MPFs-to-MXene-to-MPFs" conductive networks to accelerate the ionic/electronic transport rates. Meanwhile, the interlayer hydrogen bonds (F···HO and O···HO) contribute a high chemical stability due to a favorable tolerance to volume change caused by phase separation and structural collapse during the charge/discharge process. The synergistic effect makes MXene/MPFs film deliver a capacitance of 326.1 F g-1 at 0.1 A g-1 , 1.64 F cm-2 at 1 mA cm-2 , 694.2 F cm-3 at 1 mA cm-3 and a durability of about 30 000 cycles. The flexible symmetric supercapacitor shows an areal capacitance of 408 mF cm-2 , areal energy density of 20.4 µW h cm-2 , and capacitance retention of 95.9% after 7000 cycles. This work paves an avenue for the further exploration of 2D MOFs in flexible energy storage devices.

Activation CuFe2O4 by Hydroxylamine for Oxidation of Antibiotic Sulfamethoxazole.

A new potential oxidation process is provided by CuFe2O4/hydroxylamine (HA) system for degradation of antibiotics in water. The CuFe2O4/HA system can generate reactive oxygen species (ROS) for the degradation of sulfamethoxazole (SMX). The addition of radical scavengers, including benzoquinone (BQ) and catalase (CAT), inhibited the oxidation of SMX in CuFe2O4/HA system. Electron transfer in the CuFe2O4/HA system played a key function for the generation of ROS and the degradation of SMX. The main ROS, was the superoxide radical (O2•-) mainly generated from adsorbed oxygen (O2(A)), which came from the oxidation of the lattice oxygen (O2-(L)) in CuFe2O4. The CuFe2O4/HA system was effectively applicable for a broad pH range (approximately 5-10). In addition, the activation mechanism for CuFe2O4/HA system was studied with the target contaminant SMX. Finally, the degradation pathways of SMX were proposed under the optimal conditions in CuFe2O4/HA system.

Spatial confinement Fenton oxidation realized via tunable nanopore structure of porous carbon.

Spatially confined structure exhibits surprising physics and chemistry properties that significantly impact the thermodynamics and kinetics of oxidation reactions. Herein, porous carbons are rationally designed for tunable nanopore structures (micropores, 4.12 % ∼ 91.64 %) and diverse spatial confinement ability, as indicated by their differential enhancement performances in the Fenton oxidation. Porous carbons can alter the characteristics of the charge transport process for accelerating sustainable electron shuttle between hydrogen peroxide and iron species, and thus exhibit long-term performance (17 cycling tests). The positive spatial confinement for boosting Fenton oxidation (charge transport, mass transfer) occurs in nanochannels < 1 nm, while the diminished effect ranges of 1-1.5 nm, and the adverse effect ranges greater than 1.5 nm. The density functional theory calculation provides further support for certifying the promoted charge transport process and spatial confinement for hydroxyl radical inside the confined nanochannel structure (below 1 nm, especially) by the comparatively large electron cloud and the relatively negative adsorption energy, respectively. Coupling nanochannels with the Fenton oxidation greatly utilize hydrogen peroxide, due to spatial nanoconfinement and selective adsorption towards target contaminants. This strategy of deploying nanochannels in catalyst design can be applied for the elaborate construction of efficient nanostructured catalysts for environmental remediation.

Hydroxylamine-induced activation of permanganate for enhanced oxidation of sulfamethoxazole: Mechanism and products.

Recently, many reagents have been introduced to accelerate the formation of highly reactive intermediate Mn species from permanganate (KMnO4), thereby improving the oxidation activity of KMnO4 towards pollutants. However, most studies have mainly focused on sulfur-containing reducing agents (e.g., bisulfite and sodium sulfite), with little attention paid to nitrogen-containing reducing agents. This study found that hydroxylamine (HA) and hydroxylamine derivatives (HAs) can facilitate KMnO4 in pollutant removal. Taking sulfamethoxazole (SMX) as a target contaminant, the effect of pH, SMX concentration, KMnO4 and HA dosages, and the molar ratio of HA and KMnO4 on the degradation of SMX in the KMnO4/HA process was systematically investigated. Quenching experiments and probe analysis revealed MnO2-catalyzed KMnO4 oxidation, Mn(III) and reactive nitrogen species as the primary active species responsible for SMX oxidation in the KMnO4/HA system. Proposed transformation pathways of SMX in the KMnO4/HA system mainly involve hydroxylation and cleavage reactions. The KMnO4/HA system was more conducive to selective oxidation of SMX, 2,4-dichlorophenol, and several other pollutants, but reluctant to bisphenol S (BPS). Overall, this study proposed an effective system for eliminating pollutants, while providing mechanistic insight into HA-driven KMnO4 activation for environmental remediation.

pH-modulated oxidation of organic pollutants for water decontamination: A deep insight into reactivity and oxidation pathway.

Solution pH is one of the primary factors affecting the efficiency of water decontamination. Although the influence of pH on oxidants activation, catalyst activity, and reactive oxygen species have been widely explored, there is still a scarcity of systemic studies on the changes in the oxidation behavior of organic pollutants at different pH levels. Herein, we report the influence laws of pH on the forms, reactivities, active sites, degradation pathways, and products toxicities of organic pollutants. Changes in pH cause the protonation or deprotonation of organic pollutants and further affect their forms and chemistry (e.g., electrostatic force, hydrophobicity, and oxidation potential). The oxidation potential of organic pollutants follows the order: protonated form > pristine form > deprotonated form. Moreover, protonation or deprotonation can modify the active sites and degradation pathways of organic pollutants, wherein deprotonation renders them more susceptible to electrophilic attack, while protonation reduces their activity against electrophilic and nucleophilic attacks. Additionally, pH adjustments can modify the degradation pathway and the toxicity of transformation products. Overall, pH changes can affect the oxidation fate of organic pollutants by altering their structure, which distinguishes it from the effect of pH on oxidants or oxidant activation processes.

Soluble Tim-3 serves as a tumor prognostic marker and therapeutic target for CD8+ T cell exhaustion and anti-PD-1 resistance.

Resistance to PD-1 blockade in onco-immunotherapy greatly limits its clinical application. T cell immunoglobulin and mucin domain containing-3 (Tim-3), a promising immune checkpoint target, is cleaved by ADAM10/17 to produce its soluble form (sTim-3) in humans, potentially becoming involved in anti-PD-1 resistance. Herein, serum sTim-3 upregulation was observed in non-small cell lung cancer (NSCLC) and various digestive tumors. Notably, serum sTim-3 is further upregulated in non-responding patients undergoing anti-PD-1 therapy for NSCLC and anti-PD-1-resistant cholangiocarcinoma patients. Furthermore, sTim-3 overexpression facilitates tumor progression and confers anti-PD-1 resistance in multiple tumor mouse models. Mechanistically, sTim-3 induces terminal T cell exhaustion and attenuates CD8+ T cell response to PD-1 blockade through carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM-1). Moreover, the ADAM10 inhibitor GI254023X, which blocks sTim-3 production, reduces tumor progression in Tim-3 humanized mice and reverses anti-PD-1 resistance in human tumor-infiltrating lymphocytes (TILs). Overall, human sTim-3 holds great predictive and therapeutic potential in onco-immunotherapy.

High-valent metal-oxo species transformation and regulation by co-existing chloride: Reaction pathways and impacts on the generation of chlorinated by-products.

High-valent metal-oxo species (HMOS) have been extensively recognized in advanced oxidation processes (AOPs) owing to their high selectivity and high chemical utilization efficiency. However, the interactions between HMOS and halide ions in sewage wastewater are complicated, leading to ongoing debates on the intrinsic reactive species and impacts on remediation. Herein, we prepared three typical HMOS, including Fe(IV), Mn(V)-nitrilotriacetic acid complex (Mn(V)NTA) and Co(IV) through peroxymonosulfate (PMS) activation and comparatively studied their interactions with Cl- to reveal different reactive chlorine species (RCS) and the effects of HMOS types on RCS generation pathways. Our results show that the presence of Cl- alters the cleavage behavior of the peroxide OO bond in PMS and prohibits the generation of Fe(IV), spontaneously promoting SO4•- production and its subsequent transformation to secondary radicals like Cl• and Cl2•-. The generation and oxidation capacity of Mn(V)NTA was scarcely influenced by Cl-, while Cl- would substantially consume Co(IV) and promote HOCl generation through an oxygen-transfer reaction, evidenced by density functional theory (DFT) and deuterium oxide solvent exchange experiment. The two-electron-transfer standard redox potentials of Fe(IV), Mn(V)NTA and Co(IV) were calculated as 2.43, 2.55 and 2.85 V, respectively. Due to the different reactive species and pathways in the presence of Cl-, the amounts of chlorinated by-products followed the order of Co(II)/PMS > Fe(II)/PMS > Mn(II)NTA/PMS. Thus, this work renovates the knowledge of halide chemistry in HMOS-based systems and sheds light on the impact on the treatment of salinity-containing wastewater.

Contrasting Ultra-Low Frequency Raman and Infrared Modes in Emerging Metal Halides for Photovoltaics.

Lattice dynamics are critical to photovoltaic material performance, governing dynamic disorder, hot-carrier cooling, charge-carrier recombination, and transport. Soft metal-halide perovskites exhibit particularly intriguing dynamics, with Raman spectra exhibiting an unusually broad low-frequency response whose origin is still much debated. Here, we utilize ultra-low frequency Raman and infrared terahertz time-domain spectroscopies to provide a systematic examination of the vibrational response for a wide range of metal-halide semiconductors: FAPbI3, MAPbI x Br3-x , CsPbBr3, PbI2, Cs2AgBiBr6, Cu2AgBiI6, and AgI. We rule out extrinsic defects, octahedral tilting, cation lone pairs, and "liquid-like" Boson peaks as causes of the debated central Raman peak. Instead, we propose that the central Raman response results from an interplay of the significant broadening of Raman-active, low-energy phonon modes that are strongly amplified by a population component from Bose-Einstein statistics toward low frequency. These findings elucidate the complexities of light interactions with low-energy lattice vibrations in soft metal-halide semiconductors emerging for photovoltaic applications.

Theoretical Study on the Mechanism of Cobalt-Catalyzed C-O Silylation and Stannylation.

Organosilicon and organotin compounds have been widely used in many fields, such as organic synthesis, materials science, and biochemistry, because of their unique physical and electronic properties. Recently, two novel compounds containing C-Si or C-Sn bonds have been synthesized. These compounds can be used for late modification of drug-like molecules such as probenecid, duloxetine, and fluoxetine derivatives. However, the detailed reaction mechanisms and the influencing factors that determine selectivity are still unclear. Moreover, several questions remain that are valuable to investigate further, such as (1) the influence of the solvent and the lithium salt on the reaction of the Si/Sn-Zn reagent, (2) the stereoselective functionalization of C-O bonds, and (3) the differences between silylation and stannylation. In the current study, we have explored the above issues with density functional theory and have found that stereoselectivity was most likely caused by the oxidative addition of cobalt to the C-O bond of alkenyl acetate with chelation assistance and that transmetalation was most likely the rate-determining step. For Sn-Zn reagents, the transmetalation was achieved by anion and cation pairs, whereas for Si-Zn reagents, the process was facilitated by Co-Zn complexes.