Concurrent Asian monsoon strengthening and early modern human dispersal to East Asia during the last interglacial.

The relationship between initial Homo sapiens dispersal from Africa to East Asia and the orbitally paced evolution of the Asian summer monsoon (ASM)-currently the largest monsoon system-remains underexplored due to lack of coordinated synthesis of both Asian paleoanthropological and paleoclimatic data. Here, we investigate orbital-scale ASM dynamics during the last 280 thousand years (kyr) and their likely influences on early H. sapiens dispersal to East Asia, through a unique integration of i) new centennial-resolution ASM records from the Chinese Loess Plateau, ii) model-based East Asian hydroclimatic reconstructions, iii) paleoanthropological data compilations, and iv) global H. sapiens habitat suitability simulations. Our combined proxy- and model-based reconstructions suggest that ASM precipitation responded to a combination of Northern Hemisphere ice volume, greenhouse gas, and regional summer insolation forcing, with cooccurring primary orbital cycles of ~100-kyr, 41-kyr, and ~20-kyr. Between ~125 and 70 kyr ago, summer monsoon rains and temperatures increased in vast areas across Asia. This episode coincides with the earliest H. sapiens fossil occurrence at multiple localities in East Asia. Following the transcontinental increase in simulated habitat suitability, we suggest that ASM strengthening together with Southeast African climate deterioration may have promoted the initial H. sapiens dispersal from their African homeland to remote East Asia during the last interglacial.

N6-methyladenosine modification of linc-OIP5 confers paclitaxel resistance in breast cancer through a DDX5-dependent mechanism.

Chemoresistance is a significant obstacle in the treatment of breast cancer (BC). Due to its diverse composition, the causes of chemoresistance in BC are complex and have not been completely understood. In this article, we explored the mechanism of N6-methyladenosine (m6A)-modified long intervening noncoding RNA (linc)-OIP5 in BC chemoresistance. We successfully constructed drug-resistant cell lines MCF-7/P and MDA-MB-231/P by exposing parental MDA-MB-231 and MCF-7 cells to escalating doses of paclitaxel (PTX) and revealed multiple m6A methylation modification sites on linc-OIP5 according to the predictive analysis of the SRAMP database. Linc-OIP5 expression and m6A modification were up-regulated in PTX-resistant BC cells. Inhibition of m6A modification or linc-OIP5 knockdown facilitated PTX-resistant and parental BC cell apoptosis and repressed proliferation and migration. Mechanistically, linc-OIP5 bound to TRIM5 and reduced the ubiquitination of DDX5, thus stabilizing the DDX5 protein. Additionally, DDX5 overexpression partly abrogated the suppressing effects of inhibited m6A modification or si-linc-OIP5 on cell proliferation, migration and PTX resistance. These findings indicate that m6A-modified linc-OIP5 reduced DDX5 ubiquitination and enhanced DDX5 stability by binding to TRIM5, thereby promoting BC cell proliferation, migration and PTX resistance, and inhibiting apoptosis.

PDIA3 orchestrates effector T cell program by serving as a chaperone to facilitate the non-canonical nuclear import of STAT1 and PKM2.

Dysregulated T cell activation underpins the immunopathology of rheumatoid arthritis (RA), yet the machineries that orchestrate T cell effector program remain incompletely understood. Herein, we leveraged bulk and single-cell RNA sequencing data from RA patients and validated protein disulfide isomerase family A member 3 (PDIA3) as a potential therapeutic target. PDIA3 is remarkably upregulated in pathogenic CD4 T cells derived from RA patients and positively correlates with C-reactive protein level and disease activity score 28. Pharmacological inhibition or genetic ablation of PDIA3 alleviates RA-associated articular pathology and autoimmune responses. Mechanistically, T cell receptor signaling triggers intracellular calcium flux to activate NFAT1, a process that is further potentiated by Wnt5a under RA settings. Activated NFAT1 then directly binds to the Pdia3 promoter to enhance the expression of PDIA3, which complexes with STAT1 or PKM2 to facilitate their nuclear import for transcribing T helper 1 (Th1) and Th17 lineage-related genes, respectively. This non-canonical regulatory mechanism likely occurs under pathological conditions, as PDIA3 could only be highly induced following aberrant external stimuli. Together, our data support that targeting PDIA3 is a vital strategy to mitigate autoimmune diseases, such as RA, in clinical settings.

Momentum-Resolved Electronic Structures and Strong Electronic Correlations in Graphene-like Nitride Superconductors.

Although transition-metal nitrides have been widely applied for several decades, experimental investigations of their high-resolution electronic band structures are rare due to the lack of high-quality single-crystalline samples. Here, we report on the first momentum-resolved electronic band structures of titanium nitride (TiN) films, which are remarkable nitride superconductors. The measurements of the crystal structures and electrical transport properties confirmed the high quality of these films. More importantly, from a combination of high-resolution angle-resolved photoelectron spectroscopy and first-principles calculations, the extracted Coulomb interaction strength of TiN films can be as large as 8.5 eV, whereas resonant photoemission spectroscopy yields a value of 6.26 eV. These large values of Coulomb interaction strength indicate that superconducting TiN is a strongly correlated system. Our results uncover the unexpected electronic correlations in transition-metal nitrides, potentially providing a perspective not only to understand their emergent quantum states but also to develop their applications in quantum devices.

LncRNA MCM3AP-AS1 promotes chemoresistance in triple-negative breast cancer through the miR-524-5p/RBM39 axis.

Triple-negative breast cancer (TNBC) is the most lethal subtype of BC, with unfavorable treatment outcomes. Evidence suggests the engagement of lncRNA MCM3AP-AS1 in BC development. This study investigated the action of MCM3AP-AS1 in chemoresistance of TNBC cells. Drug-resistant TNBC cell lines SUM159PTR and MDA-MB-231R were constructed by exposure to increasing concentrations of doxorubicin/docetaxel (DOX/DXL). MCM3AP-AS1 and miR-524-5p expression levels were determined by RT-qPCR. RNA binding motif 39 (RBM39) level was measured using Western blot. Cell viability and apoptosis were assessed by CCK-8 assay and flow cytometry. The targeted binding of miR-524-5p with MCM3AP-AS1 or RBM39 was predicted by ECORI database and validated by dual-luciferase assays. The gain-and-loss of function assays were conducted in cells to investigate the interactions among MCM3AP-AS1, miR-524-5p, and RBM39. TNBC xenograft mouse models were established through subcutaneous injection of MCM3AP-AS1-silencing MDA-MB-231R cells and intraperitoneally administrated with DOX/DXL to verify the role of MCM3AP-AS1 in vivo. MCM3AP-AS1 was upregulated in drug-resistant TNBC cells, and MCM3AP-AS1 silencing could sensitize drug-resistant TNBC cells to chemotherapeutic drugs by promoting apoptosis. MCM3AP-AS1 targeted miR-524-5p. After DOX/DXL treatment, miR-524-5p inhibition partially reversed the effect of MCM3AP-AS1 silencing on inhibiting chemoresistance and promoting apoptosis of drug-resistant TNBC cells. miR-524-5p targeted RBM39. Silencing MCM3AP-AS1 promoted apoptosis via the miR-524-5p/RBM39 axis, thereby enhancing chemosensitivity of drug-resistant TNBC cells. MCM3AP-AS1 knockdown upregulated miR-524-5p, downregulated RBM39, and restrained tumor development in vivo. MCM3AP-AS1 silencing potentiates apoptosis of drug-resistant TNBC cells by upregulating miR-524-5p and downregulating RBM39, thereby suppressing chemoresistance in TNBC.

Molecular and Family Analyses of a Novel RHD1058G>C Allele in a Chinese RhD Population.

BACKGROUND: Rh(D) phenotype in a sample from a 19-year-old female patient showed weak positivity (1+). A follow-up sample was requested to further define the Rh(D) phenotype, her Rh(D) phenotype was tested by using another reagent, Rh(D) phenotype still showed weak reactivity (1+), RhCcEe phenotype was Ccee. METHODS: Seven samples from the family members of the proposita were received. The RhDCcEe phenotypes were typed by the microcolumn gel card and the unexpected antibodies were assayed by indirect anti-human globulin test (IAT). Genomic DNA was extracted from the blood sample and the novel RHD1058G>C allele was detected through an established sequence-specific primer PCR (PCR-SSP), RHD exons 1 - 10 were sequenced afterward by exon-specific amplification. The distribution of RHD1058G>C allele and RHD weak positive phenotype were investigated in the pedigrees. RESULTS: The unexpected antibodies all were negative in the family members. The novel RHD1058G>C allele was found in the proposita, her father, and grandfather. Five family members were detected serologically with the common Rh(D)-positive phenotypes either as homozygote of RHD/RHD or heterozygote of RHD/RHd. Two family members were detected as weak D phenotypes in accordance with the genotyping results by PCR-SSP, and both of them have a D1058Ce haplotype and a dce haplotype. One member, her father, was tested common Rh(D)-positive with D1058Ce haplotype and a Dce haplotype. CONCLUSIONS: These data allow us to describe the characteristics of the weak D phenotype with a novel c.RHD-1058G>C allele, which may be partial D and increase the risk of RHD alloantibody. The novel RHD1058G>C allele was inherited in three generations in a family rather than spontaneous mutation in an individual.

Bioactivities and Action Mechanisms of Ellipticine Derivatives Reported Prior to 2023.

Currently, natural products are one of the priceless options for finding novel chemical pharmaceutical entities. Ellipticine is a naturally occurring alkaloid isolated from the leaves of Ochrosia elliptica Labill. Ellipticine and its derivatives are characterized by multiple biological activities. The purpose of this review was to provide a critical and systematic assessment of ellipticine and its derivatives as bioactive molecules over the last 60 years. Publications focused mainly on the total synthesis of alkaloids of this type without any evaluation of bioactivity have been excluded. We have reviewed papers dealing with the synthesis, bioactivity evaluation and mechanism of action of ellipticine and its derivatives. It was found that ellipticine and its derivatives showed cytotoxicity, antimicrobial ability, and anti-inflammatory activity, among which cytotoxicity toward cancer cell lines was the most investigated aspect. The inhibition of DNA topoisomerase II was the most relevant mechanism for cytotoxicity. The PI3K/AKT pathway, p53 pathway, and MAPK pathway were also closely related to the antiproliferative ability of these compounds. In addition, the structure-activity relationship was deduced, and future prospects were outlined. We are confident that these findings will lay a scientific foundation for ellipticine-based drug development, especially for anticancer agents.

Effect of physical exercise in real-world settings on executive function of atypical children: A systematic review and meta-analysis.

BACKGROUND: Impaired executive function is a core symptom of cognitive impairment in atypical children. The purpose of this systematic review and meta-analysis is to explore the effectiveness of interventions for exercise in real-life settings on executive function in atypical children. METHODS: This study searched the CNKI, Wan-Fang, VIP, WOS, PubMed, Scopus and EBSCO databases. Two researchers independently selected articles, extracted data and assessed the risk of bias for the included studies. Exercise activities were categorized into open and closed skills based on the unpredictability of the environmental context and into sequential and continuous skills based on the complexity of the movement structure. Based on these two classifications, motor skills were categorized into open-sequential (e.g. basketball), open-continuous (e.g. obstacle running), closed-sequential (e.g. martial arts) and closed-continuous (e.g. swimming) skills. The SPSS 25.0 and Stata 16.0 software were used for statistical analysis. RESULTS: A total of 19 articles (23 studies) were included in the systematic review and meta-analysis. The participants were 990 atypical children with neurodevelopmental disorders. Physical exercise in real-world settings had significant intervention effects on inhibitory control (SMD = -0.592, P = 0.033), working memory (SMD = -0.473, P = 0.034) and cognitive flexibility (SMD = -0.793, P = 0.014) in atypical children. Quantitative intervention characteristics and motor skill types moderated the effect of exercise on promoting executive function in atypical children. Overall, exercise for 30-50 min, three to seven times a week for less than 10 weeks is effective in improving executive function in atypical children. Open skills and sequential skills have a positive intervention effect on more dimensions of executive function in atypical children. CONCLUSIONS: Physical exercise in real-world settings has a positive intervention effect on executive function in atypical children. We should design interventions based on the personality traits of the subject and the type of exercise they are interested in to better promote improved executive function in atypical children.

Long-term effects of nitrogen and phosphorus fertilization on profile distribution and characteristics of dissolved organic matter in fluvo-aquic soil.

Dissolved organic matter (DOM) drives numerous biogeochemical processes (e.g. carbon cycling) in agro-ecosystems and is sensitive to fertilization management. Nevertheless, changes in the quantity and quality of DOM in the vertical soil profile following long-term continuous nitrogen (N) and phosphorus (P) inputs remain unclear. In this study, the contents and optical characteristics of DOM along a 2-m soil profile were investigated using a 40-year wheat/maize rotation combined with experiments using different N and P fertilization rates in the North China Plain. The results revealed that the dissolved organic carbon (DOC) content decreased with an increase in soil depths. Compared with that in the control (no fertilization), 40-year N, P, and N + P additions increased the soil DOC content by 26%-69%, except for 270-kg N, and 67.5-kg P treatments. N + P application resulted in higher DOC contents than N-alone and P-alone applications. N, P, and N + P inputs increased or did not affect the aromaticity and hydrophobicity of DOM at 0-40 cm but reduced them from 40 to 200 cm. Compared with that in the control, N, P, and N + P inputs enhanced the content of humic acid-like substances (C1+C2+C3+C4) and decreased the content of protein-like substance (C5). C1 was the dominant component among the five DOM, representing the microbial humic component. Optical indices also indicated that soil DOM primarily originated from microbial sources. Nutrient addition accelerated transformation between complex C1 and simple C5 via promoting microbial activities. These results imply that N and P fertilizers increased the DOM content and altered its composition, thereby potentially affecting the stability of soil organic matter in the agroe-cosystems.

Bioactivities and Mechanisms of Action of Sinomenine and Its Derivatives: A Comprehensive Review.

Sinomenine, an isoquinoline alkaloid extracted from the roots and stems of Sinomenium acutum, has been extensively studied for its derivatives as bioactive agents. This review concentrates on the research advancements in the biological activities and action mechanisms of sinomenine-related compounds until November 2023. The findings indicate a broad spectrum of pharmacological effects, including antitumor, anti-inflammation, neuroprotection, and immunosuppressive properties. These compounds are notably effective against breast, lung, liver, and prostate cancers, exhibiting IC50 values of approximately 121.4 nM against PC-3 and DU-145 cells, primarily through the PI3K/Akt/mTOR, NF-κB, MAPK, and JAK/STAT signaling pathways. Additionally, they manifest anti-inflammatory and analgesic effects predominantly via the NF-κB, MAPK, and Nrf2 signaling pathways. Utilized in treating rheumatic arthritis, these alkaloids also play a significant role in cardiovascular and cerebrovascular protection, as well as organ protection through the NF-κB, Nrf2, MAPK, and PI3K/Akt/mTOR signaling pathways. This review concludes with perspectives and insights on this topic, highlighting the potential of sinomenine-related compounds in clinical applications and the development of medications derived from natural products.

Effects of Microplastics on Soil Carbon Mineralization: The Crucial Role of Oxygen Dynamics and Electron Transfer.

Although our understanding of the effects of microplastics on the dynamics of soil organic matter (SOM) has considerably advanced in recent years, the fundamental mechanisms remain unclear. In this study, we examine the effects of polyethylene and poly(lactic acid) microplastics on SOM processes via mineralization incubation. Accordingly, we evaluated the changes in carbon dioxide (CO2) and methane (CH4) production. An O2 planar optical sensor was used to detect the temporal behavior of dissolved O2 during incubation to determine the microscale oxygen heterogeneity caused by microplastics. Additionally, the changes in soil dissolved organic matter (DOM) were evaluated using a combination of spectroscopic approaches and ultrahigh-resolution mass spectrometry. Microplastics increased cumulative CO2 emissions by 160-613%, whereas CH4 emissions dropped by 45-503%, which may be attributed to the oxygenated porous habitats surrounding microplastics. Conventional and biodegradable microplastics changed the quantities of soil dissolved organic carbon. In the microplastic treatments, DOM with more polar groups was detected, suggesting a higher level of electron transport. In addition, there was a positive correlation between the carbon concentration, electron-donating ability, and CO2 emission. These findings suggest that microplastics may facilitate the mineralization of SOM by modifying O2 microenvironments, DOM concentration, and DOM electron transport capability. Accordingly, this study provides new insights into the impact of microplastics on soil carbon dynamics.

Analysis of EEG features and study of automatic classification in first-episode and drug-naïve patients with major depressive disorder.

BACKGROUND: Major depressive disorder (MDD) has a high incidence and an unknown mechanism. There are no objective and sensitive indicators for clinical diagnosis. OBJECTIVE: This study explored specific electrophysiological indicators and their role in the clinical diagnosis of MDD using machine learning. METHODS: Forty first-episode and drug-naïve patients with MDD and forty healthy controls (HCs) were recruited. EEG data were collected from all subjects in the resting state with eyes closed for 10 min. The severity of MDD was assessed by the Hamilton Depression Rating Scale (HAMD-17). Machine learning analysis was used to identify the patients with MDD. RESULTS: Compared to the HC group, the relative power of the low delta and theta bands was significantly higher in the right occipital region, and the relative power of the alpha band in the entire posterior occipital region was significantly lower in the MDD group. In the MDD group, the alpha band scalp functional connectivity was overall lower, while the scalp functional connectivity in the gamma band was significantly higher than that in the HC group. In the feature set of the relative power of the ROI in each band, the highest accuracy of 88.2% was achieved using the KNN classifier while using PCA feature selection. In the explanatory model using SHAP values, the top-ranking influence feature is the relative power of the alpha band in the left parietal region. CONCLUSIONS: Our findings reveal that the abnormal EEG neural oscillations may reflect an imbalance of excitation, inhibition and hyperactivity in the cerebral cortex in first-episode and drug-naïve patients with MDD. The relative power of the alpha band in the left parietal region is expected to be an objective electrophysiological indicator of MDD.

Bioactivities and Mechanisms of Action of Diphyllin and Its Derivatives: A Comprehensive Systematic Review.

Natural products are treasure houses for modern drug discovery. Diphyllin is a natural arylnaphthalene lignan lactone isolated from the leaf of Astilboides tabularis. Studies have found that it possesses plenty of bioactivity characteristics. In this paper, we reviewed the structure, bioactivity, and mechanism of action of diphyllin and its derivatives. The references were obtained from PubMed, Web of Science, and Science Direct databases up to August 2023. Papers without a bio-evaluation were excluded. Diphyllin and its derivatives have demonstrated V-ATPase inhibition, anti-tumor, anti-virus, anti-biofilm, anti-inflammatory, and anti-oxidant activities. The most studied activities of diphyllin and its derivatives are V-ATPase inhibition, anti-tumor activities, and anti-virus activities. Furthermore, V-ATPase inhibition activity is the mechanism of many bioactivities, including anti-tumor, anti-virus, and anti-inflammatory activities. We also found that the galactosylated modification of diphyllin is a common phenomenon in plants, and therefore, galactosylated modification is applied by researchers in the laboratory to obtain more excellent diphyllin derivatives. This review will provide useful information for the development of diphyllin-based anti-tumor and anti-virus compounds.

Gold N-Heterocyclic Carbene Catalysts for the Hydrofluorination of Alkynes Using Hydrofluoric Acid: Reaction Scope, Mechanistic Studies and the Tracking of Elusive Intermediates.

An efficient and chemoselective methodology deploying gold-N-heterocyclic carbene (NHC) complexes as catalysts in the hydrofluorination of terminal alkynes using aqueous HF has been developed. Mechanistic studies shed light on an in situ generated catalyst, formed by the reaction of Brønsted basic gold pre-catalysts with HF in water, which exhibits the highest reactivity and chemoselectivity. The catalytic system has a wide alkyl substituted-substrate scope, and stoichiometric as well as catalytic reactions with tailor-designed gold pre-catalysts enable the identification of various gold species involved along the catalytic cycle. Computational studies aid in understanding the chemoselectivity observed through examination of key mechanistic steps for phosphine- and NHC-coordinated gold species bearing the triflate counterion and the elusive key complex bearing a bifluoride counterion.

Effect of long noncoding RNA CCAT2 on drug sensitivity to 5-fluorouracil of breast cancer cells through microRNA-145 meditated by p53.

The current study was set out to investigate the mechanism by which silenced long noncoding RNA (lncRNA) colon cancer-associated transcript 2 (CCAT2) modulates the cell growth, migration, invasion, and drug sensitivity of breast cancer (BC) cells to 5-fluorouracil (5-Fu) with the involvement of miR-145 and p53. First, high CCAT2 expression was presented in BC cells and tissues. Subsequently, the links between CCAT2 expression and BC clinicopathological features were analyzed. Highly-expressed CCAT2 was linked to lymph node metastasis, positive progesterone receptor, estrogen receptor, and Ki-67 of BC cells. Then, the gain- and loss-of-function approaches were performed to measure the regulatory role of CCAT2 in the biological processes of BC cells. Silencing of CCAT2 suppressed in vitro cell growth, proliferation, invasion, migration abilities, and epithelial-mesenchymal transformation, increased cell apoptosis, and enhanced drug sensitivity of BC cells. Silencing of CCAT2 upregulated miR-145, which was poorly expressed in drug-resistant BC cells. p53 can bind to the miR-145 promoter region and increase miR-145 expression. Upregulation of miR-145 induced by silencing of CCAT2 can be invalidated by p53-siRNA. To conclude, p53-induced activation of miR-145 could be inhibited by CCAT2, while overexpression of CCAT2 could improve the drug resistance of BC cells to 5-Fu.

Infrared Vein Imaging for Insertion of Peripheral Intravenous Catheter for Patients Requiring Isolation for Severe Acute Respiratory Syndrome Coronavirus 2 Infection: A Nonrandomized Clinical Trial.

INTRODUCTION: Establishing intravenous access is essential but may be difficult to achieve for patients requiring isolation for severe acute respiratory syndrome coronavirus 2 infection. This study aimed to investigate the effectiveness of an infrared vein visualizer on peripheral intravenous catheter therapy in patients with coronavirus disease 2019. METHODS: A nonrandomized clinical trial was performed. In total, 122 patients with coronavirus disease 2019 who required peripheral intravenous cannulation were divided into 2 groups with 60 in the control group and 62 in the intervention group. A conventional venipuncture method was applied to the control group, whereas an infrared vein imaging device was applied in the intervention group. The first attempt success rate, total procedure time, and patients' satisfaction score were compared between the 2 groups using chi-square, t test, and z test (also known as Mann-Whitney U test) statistics. RESULTS: The first attempt success rate in the intervention group was significantly higher than that of control group (91.94% vs 76.67%, ꭓ2 = 5.41, P = .02). The procedure time was shorter in the intervention group (mean [SD], 211.44 [68.58] seconds vs 388.27 [88.97] seconds, t = 12.27, P < .001). Patients from the intervention group experienced a higher degree of satisfaction (7.5 vs 6, z = -3.31, P < .001). DISCUSSION: Peripheral intravenous catheter insertion assisted by an infrared vein visualizer could improve the first attempt success rate of venipuncture, shorten the procedure time, and increase patients' satisfaction.

Simple Synthetic Routes to Carbene-M-Amido (M=Cu, Ag, Au) Complexes for Luminescence and Photocatalysis Applications.

The development of novel and operationally simple synthetic routes to carbene-metal-amido (CMA) complexes of copper, silver and gold relevant for photonic applications are reported. A mild base and sustainable solvents allow all reactions to be conducted in air and at room temperature, leading to high yields of the targeted compounds even on multigram scales. The effect of various mild bases on the N-H metallation was studied in silico and experimentally, while a mechanochemical, solvent-free synthetic approach was also developed. Our photophysical studies on [M(NHC)(Cbz)] (Cbz=carbazolyl) indicate that the occurrence of fluorescent or phosphorescent states is determined primarily by the metal, providing control over the excited state properties. Consequently, we demonstrate the potential of the new CMAs beyond luminescence applications by employing a selected CMA as a photocatalyst. The exemplified synthetic ease is expected to accelerate the applications of CMAs in photocatalysis and materials chemistry.

Optically Pure C1-Symmetric Cyclic(alkyl)(amino)carbene Ruthenium Complexes for Asymmetric Olefin Metathesis.

An expedient access to the first optically pure ruthenium complexes containing C1-symmetric cyclic (alkyl)(amino)carbene ligands is reported. They demonstrate excellent catalytic performances in asymmetric olefin metathesis with high enantioselectivities (up to 92% ee). Preliminary mechanistic insights provided by density functional theory models highlight the origin of the enantioselectivity.

Barium-Catalysed Dehydrocoupling of Hydrosilanes and Borinic Acids: A Mechanistic Insight.

Two very rare cases of barium boryloxides, the homoleptic [Ba(OB{CH(SiMe3 )2 }2 )2 ⋅C7 H8 ] and the heteroleptic [{LONO4 }BaOB{CH(SiMe3 )2 }2 ] stabilised by the multidentate aminoetherphenolate {LONO4 }- , are presented, and their structural properties are discussed. The electron-deficient [Ba(OB{CH(SiMe3 )2 }2 )2 ⋅C7 H8 ] shows, in particular, resilient η6 -coordination of the toluene molecule. Together with its amido parents [Ba{N(SiMe3 )2 }2 ⋅thf2 ] and [Ba{N(SiMe3 )2 }2 ]2 , this complex catalyses the fast and chemoselective dehydrocoupling of borinic acids R2 BOH and hydrosilanes HSiR'3 , yielding borasiloxanes R2 BOSiR'3 in a controlled fashion. The assessment of substrate scope indicates that, for now, the reaction is limited to bulky borinic acids. Kinetic analysis shows that the rate-limiting step of the catalytic manifold traverses a dinuclear transition state. A detailed mechanistic scenario is proposed on the basis of DFT computations, the results of which are fully consistent with experimental data. It consists of a stepwise process with rate-determining nucleophilic attack of a metal-bound O-atom onto the incoming hydrosilane, involving throughout dinuclear catalytically active species.

Barium-Catalysed Dehydrocoupling of Hydrosilanes and Borinic Acids: A Mechanistic Insight.

Invited for the cover of this issue are the groups of Yann Sarazin at the University of Rennes and Laura Falivene at the King Abdullah University of Science and Technology. The image depicts two barium figures working in tandem to mimic the dinuclear nature of the active species in the catalytic cycle described in the manuscript. Read the full text of the article at 10.1002/chem.201904933.