Robust and efficient hydrogenation of carbonyl compounds catalysed by mixed donor Mn(I) pincer complexes

Efficient hydrogenation of ketones over the diaminophosphino manganese complex

Herein, we synthesized new manganese(I) complexes coordinated with the tetradentate ligand PNNP. The complexes show higher activity and excellent substituent tolerance in contrast to their manganese counterparts and are applicable in the hydrogenation of a wide range of aromatic, aliphatic and heterocyclic ketones to their corresponding alcohols.

Photovoltaic-driven stable electrosynthesis of H2O2 in simulated seawater and its disinfection application

Electrosynthesis of H2O2 through O2 reduction in seawater provides bright sight on the H2O2 industry, which is a prospective alternative to the intensively constructed anthraquinone process. In this work, a photovoltaic-driven flow cell system is built for the electrosynthesis of H2O2 in simulated seawater using N-doped carbon catalysts. The N-doped carbon catalysts with multiple N-doped carbon defects can achieve a record-high H2O2 production rate of 34.7 mol gcatalyst -1 h-1 under an industrially relevant current density of 500 mA cm-2 and a long-term stability over 200 h in simulated seawater (0.5 M NaCl). When driven by the photovoltaic system, a H2O2 solution of ∼1.0 wt% in 0.5 M NaCl is also obtained at about 700 mA cm-2. The obtained solution is applied for disinfection of mouse wounds, with a removal rate of 100% for Escherichia coli and negligible toxicity to living organisms. It provides bright prospects for large-scale on-site H2O2 production and on-demand disinfection.

In Situ Construction of Hollow Coral-Like Porous S-Doped g-C3N4/ZnIn2S4 S-Scheme Heterojunction for Efficient Photocatalytic Hydrogen Evolution

The rational design of visible-light-responsive catalysts is crucial for converting solar energy into hydrogen energy to promote sustainable energy development. In this work, a C─S─C bond is introduced into g-C3N4 (CN) through S doping. With the help of the flexible C─S─C bond under specific stimuli, a hollow coral-like porous structure of S-doped g-C3N4 (S-CN) is synthesized for the first time. And an S-doped g-C3N4/ZnIn2S4 (S-CN/ZIS) heterojunction catalyst is in situ synthesized based on S-CN. S0.5-CN/ZIS exhibits excellent photocatalytic hydrogen evolution (PHE) efficiency (19.25 mmol g-1 h-1), which is 2.7 times higher than that of the g-C3N4/ZnIn2S4 (CN/ZIS) catalyst (8.46 mmol g-1 h-1), with a high surface quantum efficiency (AQE) of 34.43% at 420 nm. Experiments and theoretical calculations demonstrate that the excellent photocatalytic performance is attributed to the larger specific surface area and porosity, enhanced interfacial electric field (IEF) effect, and appropriate hydrogen adsorption Gibbs free energy (ΔGH*). The synergistic effect of S doping and S-scheme heterojunction contributes to the above advancement. This study provides new insights and theoretical basis for the design of CN-based photocatalysts.

Developing a Multifunctional Cathode for Photoassisted Lithium-Sulfur Battery

Integration of solar cell and secondary battery cannot only promote solar energy application but also improve the electrochemical performance of battery. Lithium-sulfur battery (LSB) is an ideal candidate for photoassisted batteries owing to its high theoretical capacity. Unfortunately, the researches related the combination of solar energy and LSB are relatively lacking. Herein, a freestanding photoelectrode is developed for photoassisted lithium-sulfur battery (PALSB) by constructing a heterogeneous structured Au@N-TiO2 on carbon cloths (Au@N-TiO2/CC), which combines multiple advantages. The Au@N-TiO2/CC photoelectrode can produce the photoelectrons to facilitate sulfur reduction during discharge process, while generating holes to accelerate sulfur evolution during charge process, improving the kinetics of electrochemical reactions. Meanwhile, Au@N-TiO2/CC can work as an electrocatalyst to promote the conversion of intermediate polysulfides during charge/discharge process, mitigating induced side reactions. Benefiting from the synergistic effect of electrocatalysis and photocatalysis, PALSB assembled with an Au@N-TiO2/CC photoelectrode obtains ultrahigh specific capacity, excellent rate performance, and outstanding cycling performance. What is more, the Au@N-TiO2/CC assembled PALSB can be directly charged under light illumination. This work not only expands the application of solar energy but also provides a new insight to develop advanced LSBs.

Hybrid chain reaction nanoscaffold-based functional nucleic acid nanomaterial cascaded with rolling circle amplification for signal enhanced miRNA let-7a detection

A novel functional nucleic acid (FNA) nanomaterial based on hybrid chain reaction (HCR) nanoscaffolds is proposed to solve the problem of time superposition and repeated primer design in sensitive miRND detection using cascade amplification technique. Rolling circle amplification (RCA) was cascaded with the prepared FNA nanomaterials for miRNA let-7a (as a model target) sensitive detection by lateral flow assay (LFA). Under the optimal conditions, the proposed RCA-FNA-LFA assay demonstrated the specificity and accuracy for miRNA let-7a detection with a detection limit of 1.07 pM, which increased sensitivity by nearly 20 times compared with that of RCA -LFA assay. It is worth noting that the non-target-dependent self-assembly process of HCR nanoscaffolds does not take up the whole detection time, thus, less time is taken than that of the conventional cascaded method. Moreover, the proposed assay does not need to consider the system compatibility between two kinds of isothermal amplification techniques. As for detection of different miRNAs, only the homologous arm of the padlock probe of RCA needs to be changed, while the FNA nanomaterial does not need any change, which greatly simplifies the primer design of the cascaded amplification techniques. With further development, the proposed RCA-FNA-LFA assay might achieve more sensitive and faster results to better satisfy the requirements of clinical diagnosis combing with more sensitive labels or small strip reader.

Phylogenomic insights into the diversity and evolution of Palearctic vipers

Despite decades of molecular research, phylogenetic relationships in Palearctic vipers (genus Vipera) still essentially rely on a few loci, such as mitochondrial barcoding genes. Here we examined the diversity and evolution of Vipera with ddRAD-seq data from 33 representative species and subspecies. Phylogenomic analyses of ∼ 1.1 Mb recovered nine major clades corresponding to known species/species complexes which are generally consistent with the mitochondrial phylogeny, albeit with a few deep discrepancies that highlight past hybridization events. The most spectacular case is the Italian-endemic V. walser, which is grouped with the alpine genetic diversity of V. berus in the nuclear tree despite carrying a divergent mitogenome related to the Caucasian V. kaznakovi complex. Clustering analyses of SNPs suggest potential admixture between diverged Iberian taxa (V. aspis zinnikeri and V. seoanei), and confirm that the Anatolian V. pontica corresponds to occasional hybrids between V. (ammodytes) meridionalis and V. kaznakovi. Finally, all analyzed lineages of the V. berus complex (including V. walser and V. barani) form vast areas of admixture and may be delimited as subspecies. Our study sets grounds for future taxonomic and phylogeographic surveys on Palearctic vipers, a group of prime interest for toxinological, ecological, biogeographic and conservation research.

Air-Stable Arene Manganese Complexes as Catalysts for the Syngas-Assisted Direct Reductive Amination, Cyanation of Aldehyde, and CO2 Fixation by Epoxide with High Functional Groups Tolerance

Manganese complexes [(arene)Mn(CO)3]+ were prepared in one step from arenes and Mn(CO)5Br. They were found to be efficient catalysts in the carbonyl cyanation with TMSCN, CO2 fixation by epoxides, and direct reductive amination in the presence of syngas. The amination reaction tolerated various reducible functional groups. The synergy of carbon monoxide and hydrogen in syngas provides high efficiency of the catalytic system. The developed protocols do not require an inert atmosphere, and the catalysts can be handled in air.

Intelligent Reconfiguration-Promoted Cellular Internalization of Core-Shell DNA Nanoprobe Equipped with Successive Dual Stimuli-Responsive Protective Satellites for Amplification Fluorescence Imaging of Tumor Cells

Although DNA probes have attracted increasing interest for precise tumor cell identification by imaging intracellular biomarkers, the requirement of commercial transfection reagents, limited targeting ligands, and/or non-biocompatible inorganic nanostructures has hampered the clinic translation. To circumvent these shortcomings, a reconfigurable ES-NC (Na+-dependent DNAzyme (E)-based substrate (S) cleavage core/shell DNA nanocluster (NC)) entirely from DNA strands is assembled for precise imaging of cancerous cells in a successive dual-stimuli-responsive manner. This nanoprobe is composed of a strung DNA tetrahedral satellites-based protective (DTP) shell, parallelly aligned target-responsive sensing (PTS) interlayer, and hydrophobic cholesterol-packed innermost layer (HCI core). Tetrahedral axial rotation-activated reconfiguration of DTP shell promotes the exposure of interior hydrophobic moieties, enabling cholesterol-mediated cellular internalization without auxiliary elements. Within cells, over-expressed glutathione triggers the disassembly of the DTP protective shell (first stimulus), facilitating target-stimulated signal transduction/amplification process (second stimuli). Target miRNA-21 is detected down to 10.6 fM without interference from coexisting miRNAs. Compared with transfection reagent-mediated counterpart, ES-NC displays a higher imaging ability, resists nuclease degradation, and has no detectable damage to healthy cells. The blind test demonstrates that the ES-NC is suitable for the identification of cancerous cells from healthy cells, indicating a promising tool for early diagnosis and prediction of cancer.

Efficient electrocatalytic reduction of CO2 to CO enhanced by the synergistic effect of N,P on carbon aerogel

A metal-free catalyst, N,P-codoped carbon aerogel, was used to realize the high efficiency reduction of CO2 to CO. Therein, the pyridinic N acts as the active center to activate and reduce CO2 and the atom of P acts as the "transition atom" of the proton to reduce the free energy barrier from *CO2 to *COOH.

Chemoselective Hydrogenation of α,β-Unsaturated Ketones Catalyzed by a Manganese(I) Hydride Complex

Here, we report the chemoselective hydrogenation of α,β-unsaturated ketones catalyzed by a well-defined Mn(I) PCNHCP pincer complex [(PCNHCP)Mn(CO)2H] (1). The reaction is compatible with a wide variety of functional groups that include halides, esters, amides, nitriles, nitro, alkynes, and alkenes, and for most substrates occurs readily at ambient hydrogen pressure (1-2 bar). Mechanistic studies and deuterium labeling experiments reveal a non-cooperative mechanism, which is further discussed in this report.

A Recyclable Electrochemical Reduction of Aldehydes and Ketones to Alcohols Using Water as the Hydrogen Source and Solvent

There are several challenging problems such as the usage of combustible and hazardous hydrogen sources and severe environmental pollution in the conventional reduction of aldehydes/ketones to alcohols. We report here a practical, safe, and green electrochemical reduction, which solves these problems to a large extent. Through an undivided cell, Zn(+) and Sn(-) as the electrode, tetrabutylammonium chloride (TBAC) as the electrolyte, water as the solvent and hydrogen source, a wide range of aldehydes and ketones are converted into the corresponding alcohols in mild conditions. Furthermore, the electrolytes and water can be recycled, and reductive deuteration can be achieved by simply using D2O as the solvent. Finally, the reduction can be smoothly scaled up to a kilogram level.

Reduction of sulfoxides catalyzed by the commercially available manganese complex MnBr(CO)5

A new methodology for the reduction of a wide variety of aliphatic and aromatic sulfoxides catalyzed by the air-stable, cheap and commercially available manganese catalyst MnBr(CO)5 with excellent yields is reported in this work. The catalytic system MnBr(CO)5/PhSiH3 is highly chemoselective, allowing the effective reduction of the SO bond in the presence of different functional groups.

Linearly Interlinked Fe-Nx-Fe Single Atoms Catalyze High-Rate Sodium-Sulfur Batteries

Linearly interlinked single atoms offer unprecedented physiochemical properties, but their synthesis for practical applications still poses significant challenges. Herein, linearly interlinked iron single-atom catalysts that are loaded onto interconnected carbon channels as cathodic sulfur hosts for room-temperature sodium-sulfur batteries are presented. The interlinked iron single-atom exhibits unique metallic iron bonds that facilitate the transfer of electrons to the sulfur cathode, thereby accelerating the reaction kinetics. Additionally, the columnated and interlinked carbon channels ensure rapid Na+ diffusion kinetics to support high-rate battery reactions. By combining the iron atomic chains and the topological carbon channels, the resulting sulfur cathodes demonstrate effective high-rate conversion performance while maintaining excellent stability. Remarkably, even after 5000 cycles at a current density of 10 A g-1, the Na-S battery retains a capacity of 325 mAh g-1. This work can open a new avenue in the design of catalysts and carbon ionic channels, paving the way to achieve sustainable and high-performance energy devices.

Impact of the Methylene Bridge Substitution in Chelating NHC-Phosphine Mn(I) Catalyst for Ketone Hydrogenation

Systematic modification of the chelating NHC-phosphine ligand (NHC = N-heterocyclic carbene) in highly efficient ketone hydrogenation Mn(I) catalyst fac-[(Ph2PCH2NHC)Mn(CO)3Br] has been performed and the catalytic activity of the resulting complexes was evaluated using acetophenone as a benchmark substrate. While the variation of phosphine and NHC moieties led to inferior results than for a parent system, the incorporation of a phenyl substituent into the ligand methylene bridge improved catalytic performance by ca. 3 times providing maximal TON values in the range of 15000-20000. Mechanistic investigation combining experimental and computational studies allowed to rationalize this beneficial effect as an enhanced stabilization of reaction intermediates including anionic hydride species fac-[(Ph2PC(Ph)NHC)Mn(CO)3H]- playing a crucial role in the hydrogenation process. These results highlight the interest of such carbon bridge substitution strategy being rarely employed in the design of chemically non-innocent ligands.

Biomedical applications, perspectives and tag design concepts in the cell - silent Raman window

Spectroscopic studies increasingly employ Raman tags exhibiting a signal in the cell - silent region of the Raman spectrum (1800-2800 cm-1), where bands arising from biological molecules are inherently absent. Raman tags bearing functional groups which contain a triple bond, such as alkyne and nitrile or a carbon-deuterium bond, have a distinct vibrational frequency in this region. Due to the lack of spectral background and cell-associated bands in the specific area, the implementation of those tags can help overcome the inherently poor signal-to-noise ratio and presence of overlapping Raman bands in measurements of biological samples. The cell - silent Raman tags allow for bioorthogonal imaging of biomolecules with improved chemical contrast and they have found application in analyte detection and monitoring, biomarker profiling and live cell imaging. This review focuses on the potential of the cell - silent Raman region, reporting on the tags employed for biomedical applications using variants of Raman spectroscopy.

Laser-Ignited Lipid Peroxidation Nanoamplifiers for Strengthening Tumor Photodynamic Therapy Through Aggravating Ferroptotic Propagation and Sustainable High Immunogenicity

Photodynamic therapy (PDT) is extensively investigated for tumor therapy in the clinic. However, the efficacy of PDT is severely limited by the tissue penetrability of light, short effective half-life and radius of reactive oxygen species (ROS), and the weak immunostimulatory effect. In this study, a glutathione (GSH)-activatable nano-photosensitizer is developed to load with arachidonic acid (AA) and camouflage by erythrocyte membrane, which serves as a laser-ignited lipid peroxidation nanoamplifier (MAR). The photosensitive effect of MAR is recovered accompanied by the degradation in the tumor microenvironment and triggers the peroxidation of AA upon laser excitation. Interestingly, it aggravates the propagation of ferroptosis among cancer cells by driving the continuous lipid peroxidation chain reactions with the participation of the degradation products, ferrous ions (Fe2+), and AA. Consequently, even the deep-seated tumor cells without illumination also undergo ferroptosis owing to the propagation of ferroptotic signal. Moreover, the residual tumor cells undergoing ferroptosis still maintain high immunogenicity after PDT, thus continuously triggering sufficient tumor-associated antigens (TAAs) release to remarkably promote the anti-tumor immune response. Therefore, this study will provide a novel "all-in-one" nano-photosensitizer that not only amplifies the damaging effect and expands the effective range of PDT but also improves the immunostimulatory effect after PDT.

Bacteria-Based Backpacks to Enhance Adoptive Macrophage Transfer against Solid Tumors

Adoptive cell therapy has emerged as a promising approach for cancer treatment. However, the transfer of macrophages exhibits limited efficacy against solid tumors due to the dynamic cellular phenotypic shift from antitumor to protumor states within the immunosuppressive tumor microenvironment. In this study, a strategy of attaching bacteria to macrophages (Mø@bac) is reported that endows adoptively infused macrophages with durable stimulation by leveraging the intrinsic immunogenicity of bacteria. These attached bacteria, referred to as backpacks, are encapsulated with adhesive nanocoatings and can sustainably control the cellular phenotypes in vivo. Moreover, Mø@bac can repolarize endogenous tumor-associated macrophages, leading to a more robust immune response and thus reducing the tumor progression in a murine 4T1 cancer model without any side effects. This study utilizing bacteria as cellular backpacks opens a new avenue for the development of cell therapies.

Effects of the COVID-19 pandemic on youth mental health: a cross-sectional study on eating disorder patients and their unaffected siblings

BACKGROUND

Adolescence has emerged as a particularly vulnerable phase during the COVID-19 pandemic, with eating disorders (EDs) representing a prominent psychopathological challenge linked to the restrictions imposed by the pandemic. Emerging evidence suggests that not only individuals with EDs but also their healthy siblings (HS) may experience unique psychological effects in this context. However, the existing literature on this topic remains limited. This study seeks to examine and compare the effects of the pandemic on adolescents and adults, with a specific focus on the impact of containment measures, disruptions in daily routines, and alterations in life trajectories, for both individuals with EDs and their HS.

METHODS

We enrolled 273 individuals, including those diagnosed with EDs and their HS. Among the participants, 120 were under the age of 19. Multiple self-report questionnaires were administered to assess the psychological impact of 1 year of the COVID-19 pandemic. These assessments covered a range of psychological constructs, including posttraumatic symptoms, general psychopathology, and eating-related concerns.

RESULTS

Notably, adolescent patients with EDs demonstrated the highest psychopathological scores within our sample. They were the sole subgroup to surpass clinical cutoffs, exhibiting more pronounced issues concerning eating-related concerns and general psychological well-being. Our findings also shed light on the unique experiences of HS during the pandemic.

CONCLUSION

Our findings highlight the specific psychological burden endured by adolescents with EDs throughout the COVID-19 pandemic, emphasizing the vulnerability of this demographic. Moreover, the experiences of HS, often overlooked in the literature, warrant increased attention in future health programs and interventions.

Protein nanobarcodes enable single-step multiplexed fluorescence imaging

Multiplexed cellular imaging typically relies on the sequential application of detection probes, as antibodies or DNA barcodes, which is complex and time-consuming. To address this, we developed here protein nanobarcodes, composed of combinations of epitopes recognized by specific sets of nanobodies. The nanobarcodes are read in a single imaging step, relying on nanobodies conjugated to distinct fluorophores, which enables a precise analysis of large numbers of protein combinations. Fluorescence images from nanobarcodes were used as input images for a deep neural network, which was able to identify proteins with high precision. We thus present an efficient and straightforward protein identification method, which is applicable to relatively complex biological assays. We demonstrate this by a multicell competition assay, in which we successfully used our nanobarcoded proteins together with neurexin and neuroligin isoforms, thereby testing the preferred binding combinations of multiple isoforms, in parallel.

HiREX: High-Throughput Reactivity Exploration for Extended Databases of Transition-Metal Catalysts

A method is introduced for the automated analysis of reactivity exploration for extended in silico databases of transition-metal catalysts. The proposed workflow is designed to tackle two key challenges for bias-free mechanistic explorations on large databases of catalysts: (1) automated exploration of the chemical space around each catalyst with unique structural and chemical features and (2) automated analysis of the resulting large chemical data sets. To address these challenges, we have extended the application of our previously developed ReNeGate method for bias-free reactivity exploration and implemented an automated analysis procedure to identify the classes of reactivity patterns within specific catalyst groups. Our procedure applied to an extended series of representative Mn(I) pincer complexes revealed correlations between structural and reactive features, pointing to new channels for catalyst transformation under the reaction conditions. Such an automated high-throughput virtual screening of systematically generated hypothetical catalyst data sets opens new opportunities for the design of high-performance catalysts as well as an accelerated method for expert bias-free high-throughput in silico reactivity exploration.

Accumulative Rolling Mg/PLLA Composite Membrane with Lamellar Heterostructure for Enhanced Bacteria Inhibition and Rapid Bone Regeneration

Developing composite materials with optimized mechanics, degradation, and bioactivity for bone regeneration has long been a crucial mission. Herein, a multifunctional Mg/Poly-l-lactic acid (Mg/PLLA) composite membrane based on the "materials plain" concept through the accumulative rolling (AR) method is proposed. Results show that at a rolling ratio of 75%, the comprehensive mechanical properties of the membrane in the rolling direction are self-reinforced significantly (elongation at break ≈53.2%, tensile strength ≈104.0 MPa, Young's modulus ≈2.13 GPa). This enhancement is attributed to the directional arrangement and increased crystallization of PLLA molecular chains, as demonstrated by SAXS and DSC results. Furthermore, the AR composite membrane presents a lamellar heterostructure, which not only avoids the accumulation of Mg microparticles (MgMPs) but also regulates the degradation rate. Through the contribution of bioactive MgMPs and their photothermal effect synergistically, the membrane effectively eliminates bacterial infection and accelerates vascularized bone regeneration both in vitro and in vivo. Notably, the membrane exhibits outstanding rat skull bone regeneration performance in only 4 weeks, surpassing most literature reports. In short, this work develops a composite membrane with a "one stone, four birds" effect, opening an efficient avenue toward high-performance orthopedic materials.

L-Arginine-Loaded Gold Nanocages Ameliorate Myocardial Ischemia/Reperfusion Injury by Promoting Nitric Oxide Production and Maintaining Mitochondrial Function

Cardiovascular disease is the leading cause of death worldwide. Reperfusion therapy is vital to patient survival after a heart attack but can cause myocardial ischemia/reperfusion injury (MI/RI). Nitric oxide (NO) can ameliorate MI/RI and is a key molecule for drug development. However, reactive oxygen species (ROS) can easily oxidize NO to peroxynitrite, which causes secondary cardiomyocyte damage. Herein, L-arginine-loaded selenium-coated gold nanocages (AAS) are designed, synthesized, and modified with PCM (WLSEAGPVVTVRALRGTGSW) to obtain AASP, which targets cardiomyocytes, exhibits increased cellular uptake, and improves photoacoustic imaging in vitro and in vivo. AASP significantly inhibits oxygen glucose deprivation/reoxygenation (OGD/R)-induced H9C2 cell cytotoxicity and apoptosis. Mechanistic investigation revealed that AASP improves mitochondrial membrane potential (MMP), restores ATP synthase activity, blocks ROS generation, and prevents NO oxidation, and NO blocks ROS release by regulating the closing of the mitochondrial permeability transition pore (mPTP). AASP administration in vivo improves myocardial function, inhibits myocardial apoptosis and fibrosis, and ultimately attenuates MI/RI in rats by maintaining mitochondrial function and regulating NO signaling. AASP shows good safety and biocompatibility in vivo. This findings confirm the rational design of AASP, which can provide effective treatment for MI/RI.

Bis(N-Heterocyclic Carbene) Manganese(I) Complexes: Efficient and Simple Hydrogenation Catalysts

The use of bis(NHC) manganese(I) complexes 3 as catalysts for the hydrogenation of esters was investigated. For that purpose, a series of complexes has been synthesized via an improved two step procedure utilizing bis(NHC)-BEt3 adducts. By applying complexes 3 with KHBEt3 as additive, various aromatic and aliphatic esters were hydrogenated successfully at mild temperatures and low catalyst loadings, highlighting the efficiency of the novel catalytic system. The versatility of the developed catalytic system was further demonstrated by the hydrogenation of other substrate classes like ketones, nitriles, N-heteroarenes and alkenes. Mechanistic experiments and DFT calculations indicate an inner sphere mechanism with the loss of one CO ligand and reveal the role of BEt3 as cocatalyst.

Synthesis, Characterization, and Reactivity of a (PPP) Pincer-Ligated Manganese Carbonyl Complex: Polarity Reversal Imparted by the Electrophilic Nature of a Planar Mn-P(NR2)2 Fragment

The bonding interactions of a synthesized pincer-ligated manganese dicarbonyl complex featuring an N-heterocyclic phosphenium (NHP+) central moiety are explored. The pincer ligand [PPP]Cl was coordinated to a manganese center using Mn(CO)5Br and 254 nm light to afford the chlorophosphine complex (PPClP)Mn(CO)2Br (2) as a mixture of halide exchange products and stereoisomers. The target dicarbonyl species (PPP)Mn(CO)2 (3) was prepared by treatment of 2 with 2 equiv of the reductant KC8. Computational investigations and analysis of structural parameters were used to elucidate multiple bonding interactions between the Mn center and the PNHP atom in 3. The generation of a product of formal H2 addition, (PPHP)Mn(CO)2H (4), was achieved through the dehydrogenation of NH3BH3, affording a 2:1 mixture of 4syn:4anti stereoisomers. The nucleophilic nature of the Mn center and the electrophilic nature of the PNHP moiety were demonstrated through hydride addition and protonation of 3 to produce K(THF)2[(PPHP)Mn(CO)2] (6) and (PPClP)Mn(CO)2H (5), respectively. The observed reactivity suggests that 3 is best described as a Mn-I/NHP+ complex, in contrast to pincer-ligated dicarbonyl manganese analogues typically assigned as MnI species.

Hydrosilylation of Terminal Alkynes Catalyzed by an Air-Stable Manganese-NHC Complex

In recent years, catalysis with base metal manganese has received a significant amount of interest. Catalysis with manganese complexes having N-heterocyclic carbenes (NHCs) is relatively underdeveloped in comparison to the extensively investigated manganese catalysts possessing pincer ligands (particularly phosphine-based ligands). Herein, we describe the synthesis of two imidazolium salts decorated with picolyl arms (L₁ and L₂) as NHC precursors. Facile coordination of L₁ and L₂ with MnBr(CO)₅ in the presence of a base resulted in the formation manganese(I)-NHC complexes (1 and 2) as an air-stable solid in good isolated yield. Single-crystal X-ray analysis revealed the structure of the cationic complexes [Mn(CO)₃(NHC)][PF₆] with tridentate N,C,N binding of the NHC ligand in a facile fashion. Along with a few known manganese(I) complexes, these Mn(I)-NHC complexes 1 and 2 were tested for the hydrosilylation of terminal alkynes. Complex 1 was proved to be an effective catalyst for the hydrosilylation of terminal alkynes with good selectivity toward the less thermodynamically stable β-(Z)-vinylsilanes. This method provided good regioselectivity (anti-Markovnikov addition) and stereoselectivity (β-(Z)-product). Experimental evidence suggested that the present hydrosilylation pathway involved an organometallic mechanism with manganese(I)-silyl species as a possible reactive intermediate.

Metal phosphine aldehyde complexes and their application in Cu-free Sonogashira and Suzuki-Miyaura cross-coupling reactions

Transition metal coordination chemistry and catalysis are rife with phosphine ligands. One of the rather less studied members of the phosphine ligand family are phosphine aldehydes. We have synthesised 3-(diphenylphosphino)propanal (PCHO) with a slight modification of the known procedure and studied its complexation behaviour with palladium(II) and platinum(II). The catalytic activity of the palladium(II) phosphine aldehyde complexes was investigated in Cu-free Sonogashira and Suzuki-Miyaura cross-coupling reactions. Furthermore, the homogeneous nature of the catalytically active species was confirmed.

Base- and Additive-Free Carbon Dioxide Hydroboration to Methoxyboranes Catalyzed by Non-Pincer-Type Mn(I) Complexes

Well-defined, bench stable Mn(I) non-pincer-type complexes were tested as earth-abundant transition metal catalysts for the selective reduction of CO₂ to boryl-protected MeOH in the presence of pinacolborane (HBpin). Essentially, quantitative yields were obtained under mild reaction conditions (1 bar CO₂, 60 °C), without the need of any base or additives, in the presence of the alkylcarbonyl Mn(I) bis(phosphine) complexes fac-[Mn(CH₂CH₂CH₃)(dippe)(CO)₃] [Mn1, dippe = 1,2-bis(diisopropylphosphino)ethane] and [Mn(dippe)(CO)₂{(μ-H)₂(Bpin)}] (Mn4), that is obtained by reaction of the bench-stable precatalyst Mn1 with HBpin via elimination of butanal. Preliminary mechanistic details were obtained by a combination of NMR experiments and monitoring of the catalytic reactions.

Efficient Hydrogenation of N-Heterocycles Catalyzed by NNP-Manganese(I) Pincer Complexes at Ambient Temperature

Manganese-catalyzed hydrogenation reactions have aroused widespread interest in recent years. Among the catalytic systems described, especially PNP- and NNP-Mn pincer catalysts have been reported for the hydrogenation of aldehydes, ketones, nitriles, aldimines and esters. Furthermore, NNP-Mn pincer compounds are efficient catalysts for the hydrogenolysis of less reactive amides, ureas, carbonates, and carbamates. Herein, the synthesis and application of specific imidazolylaminophosphine ligands and the corresponding Mn pincer complexes are described. These new catalysts have been characterized and studied by a combination of experimental and theoretical investigations, and their catalytic activities have been tested in several hydrogenation reactions with good to excellent performance. Especially, the reduction of N-heterocycles can be performed under very mild conditions.

Genome-wide identification and expression analysis of Raf-like kinase gene family in pepper (Capsicum annuum L.)

As highly conserved signaling pathway modules, mitogen-activated protein kinase (MAPK) cascades play vital roles in a diverse range of stress and hormonal responses in plants. Among the established components of MAPK cascades, Raf-like MAPK kinase kinases (MAPKKKs) are associated with abscisic acid (ABA) signaling and osmotic stress responses. However, despite the availability of a pepper reference genome, few of the Raf-like kinases in pepper plants have been functionally characterized. In this study, we isolated 47 putative Raf-like kinase genes from the pepper genome based on in silico analysis, which were classified into two major categories, namely, groups B and C (further sub-grouped into B1-B4 and C1-C7, respectively) and named sequentially as CaRaf1 to CaRaf47. Subcellular localization prediction analysis revealed that most of the group B CaRaf-like kinases are probably nuclear-localized, whereas a majority of group C members targeted into the cytoplasm. Transcriptional regulation of the 47 CaRaf genes in response to treatment with ABA, drought, NaCl, and mannitol was quantitatively analyzed by reverse-transcription PCR analysis. This revealed a significant induction of subgroup B3, C2, C3, and C5 members, indicating that these genes may be functionally associated with the response to osmotic stress, mediated via both ABA-dependent and -independent pathways. The findings of this study can accordingly serve as a basis for the identification of CaRaf genes associated with the regulation of ABA signaling and osmotic stress response and thus contribute to enhancing our understanding of the biological functions of CaRaf kinases in the responses of plants to different abiotic stresses.

ReNeGate: A Reaction Network Graph-Theoretical Tool for Automated Mechanistic Studies in Computational Homogeneous Catalysis

Exploration of the chemical reaction space of chemical transformations in multicomponent mixtures is one of the main challenges in contemporary computational chemistry. To remove expert bias from mechanistic studies and to discover new chemistries, an automated graph-theoretical methodology is proposed, which puts forward a network formalism of homogeneous catalysis reactions and utilizes a network analysis tool for mechanistic studies. The method can be used for analyzing trajectories with single and multiple catalytic species and can provide unique conformers of catalysts including multinuclear catalyst clusters along with other catalytic mixture components. The presented three-step approach has the integrated ability to handle multicomponent catalytic systems of arbitrary complexity (mixtures of reactants, catalyst precursors, ligands, additives, and solvents). It is not limited to predefined chemical rules, does not require prealignment of reaction mixture components consistent with a reaction coordinate, and is not agnostic to the chemical nature of transformations. Conformer exploration, reactive event identification, and reaction network analysis are the main steps taken for identifying the pathways in catalytic systems given the starting precatalytic reaction mixture as the input. Such a methodology allows us to efficiently explore catalytic systems in realistic conditions for either previously observed or completely unknown reactive events in the context of a network representing different intermediates. Our workflow for the catalytic reaction space exploration exclusively focuses on the identification of thermodynamically feasible conversion channels, representative of the (secondary) catalyst deactivation or inhibition paths, which are usually most difficult to anticipate based solely on expert chemical knowledge. Thus, the expert bias is sought to be removed at all steps, and the chemical intuition is limited to the choice of the thermodynamic constraint imposed by the applicable experimental conditions in terms of threshold energy values for allowed transformations. The capabilities of the proposed methodology have been tested by exploring the reactivity of Mn complexes relevant for catalytic hydrogenation chemistry to verify previously postulated activation mechanisms and unravel unexpected reaction channels relevant to rare deactivation events.

Advanced nanomaterials for highly efficient CO2 photoreduction and photocatalytic hydrogen evolution

At present, CO₂ photoreduction to value-added chemicals/fuels and photocatalytic hydrogen generation by water splitting are the most promising reactions to fix two main issues simultaneously, rising CO₂ levels and never-lasting energy demand. CO₂, a major contributor to greenhouse gases (GHGs) with about 65% of the total emission, is known to cause adverse effects like global temperature change, ocean acidification, greenhouse effects, etc. The idea of CO₂ capture and its conversion to hydrocarbons can control the further rise of CO₂ levels and help in producing alternative fuels that have several further applications. On the other hand, hydrogen being a zero-emission fuel is considered as a clean and sustainable form of energy that holds great promise for various industrial applications. The current review focuses on the discussion of the recent progress made in designing efficient photocatalytic materials for CO₂ photoreduction and hydrogen evolution reaction (HER). The scope of the current study is limited to the TiO₂ and non-TiO₂ based advanced nanomaterials (i.e. metal chalcogenides, MOFs, carbon nitrides, single-atom catalysts, and low-dimensional nanomaterials). In detail, the influence of important factors that affect the performance of these photocatalysts towards CO₂ photoreduction and HER is reviewed. Special attention is also given in this review to provide a brief account of CO₂ adsorption modes on the catalyst surface and its subsequent reduction pathways/product selectivity. Finally, the review is concluded with additional outlooks regarding upcoming research on promising nanomaterials and reactor design strategies for increasing the efficiency of the photoreactions.

Room temperature chemoselective hydrogenation of C[double bond, length as m-dash]C, C[double bond, length as m-dash]O and C[double bond, length as m-dash]N bonds by using a well-defined mixed donor Mn(i) pincer catalyst

Chemoselective hydrogenation of C[double bond, length as m-dash]C, C[double bond, length as m-dash]O and C[double bond, length as m-dash]N bonds in α,β-unsaturated ketones, aldehydes and imines is accomplished at room temperature (27 °C) using a well-defined Mn(i) catalyst and 5.0 bar H₂. Amongst the three mixed-donor Mn(i) complexes developed, κ³-(^R2PN³N^Pyz)Mn(CO)₂Br (R = Ph, ⁱPr, ^t Bu); the ^t Bu-substituted complex ( ^tBu2PN³N^Pyz)Mn(CO)₂Br shows exceptional chemoselective catalytic reduction of unsaturated bonds. This hydrogenation protocol tolerates a range of highly susceptible functionalities, such as halides (-F, -Cl, -Br, and -I), alkoxy and hydroxy, including hydrogen-sensitive moieties like acetyl, nitrile, nitro, epoxide, and unconjugated alkenyl and alkynyl groups. Additionally, the disclosed method applies to indole, pyrrole, furan, thiophene, and pyridine-containing unsaturated ketones leading to the corresponding saturated ketones. The C[double bond, length as m-dash]C bond is chemoselectively hydrogenated in α,β-unsaturated ketones, while the aldehyde's C[double bond, length as m-dash]O bond and imine's C[double bond, length as m-dash]N bond are preferentially reduced over the C[double bond, length as m-dash]C bond. A detailed mechanistic study highlighted the non-innocent behavior of the ligand in the ( ^tBu2PN³N^Pyz)Mn(i) complex and indicated a metal-ligand cooperative catalytic pathway. The molecular hydrogen (H₂) acts as a hydride source, whereas MeOH provides a proton for hydrogenation. DFT energy calculations supported the facile progress of most catalytic steps, involving a crucial turnover-limiting H₂ activation.

Actions to reduce carbon footprint in materials to healthcare buildings

Building sector is a major contributor to the emissions of pollutant gases, which are responsible for health-damaging effects of climate change. To quantify and reduce these emissions. This comparative study is presented between two buildings that could have a sanitary or any other type of use. Both buildings have similar characteristics, except for their structures, one made of metal and the other of concrete. The design, structural calculation and three-dimensional dimensioning were performed using Building Information Modeling (BIM). The budget and the product carbon footprint study were also carried out, to calculate the level of emissions of each building. The study determined higher emissions for the metal-structured building, with 621.234 tCO₂/t_material compared to 446.707 tCO₂/t_material for the concrete building. To reduce these emissions, measures related to the replacement of the previously selected materials, by other materials with lower emission rates and identical functionality were presented, such as the replacement of metal building roof polyurethane, or the composition of cement for the concrete building. Both actions represented a reduction of 84.61% CO₂ emissions for metal envelope building and 31.765% for the concrete structure. The results of this work will help to select more sustainable materials to use in the renovation of existing buildings, or in the construction of new buildings. For example, health-related buildings, currently in high demand, given the current pandemic situation caused by COVID-19.

TiCl4-Catalyzed Hydroboration of Ketones with Ammonia Borane

Investigation of a variety of Lewis acids for the hydroboration-hydrolysis (reduction) of ketones with amine-boranes has revealed that catalytic (10 mol %) titanium tetrachloride (TiCl₄) in diethyl ether at room temperature immensely accelerates the reaction of ammonia borane. The product alcohols are produced in good to excellent yields within 30 min, even with ketones which typically requires 24 h or longer to reduce under uncatalyzed conditions. Several potentially reactive functionalities are tolerated, and substituted cycloalkanones are reduced diastereoselectively to the thermodynamic product. A deuterium labeling study and ¹¹B NMR analysis of the reaction have been performed to verify the proposed hydroboration mechanism.

Switching between Hydrogenation and Olefin Transposition Catalysis via Silencing NH Cooperativity in Mn(I) Pincer Complexes

While Mn-catalyzed (de)hydrogenation of carbonyl derivatives has been well established, the reactivity of Mn hydrides with olefins remains very rare. Herein, we report a Mn(I) pincer complex that effectively promotes site-controlled transposition of olefins. This reactivity is shown to emerge once the N–H functionality within the Mn/NH bifunctional complex is suppressed by alkylation. While detrimental for carbonyl (de)hydrogenation, such masking of the cooperative N–H functionality allows for the highly efficient conversion of a wide range of allylarenes to higher-value 1-propenybenzenes in near-quantitative yield with excellent stereoselectivities. The reactivity toward a single positional isomerization was also retained for long-chain alkenes, resulting in the highly regioselective formation of 2-alkenes, which are less thermodynamically stable compared to other possible isomerization products. The detailed mechanistic analysis of the reaction between the activated Mn catalyst and olefins points to catalysis operating via a metal–alkyl mechanism—one of the three conventional transposition mechanisms previously unknown in Mn complexes.

Synthesis of Fungal Cell Wall Oligosaccharides and Their Ability to Trigger Plant Immune Responses

Oligosaccharide fragments of fungal cell wall glycans are important molecular probes for studying both the biology of fungi and fungal infections of humans, animals, and plants. The fungal cell wall contains large amounts of various polysaccharides that are ligands for pattern recognition receptors (PRRs), eliciting an immune response upon recognition. Towards the establishment of a glycan array platform for the identification of new ligands of plant PRRs, tri-, penta-, and heptasaccharide fragments of different cell wall polysaccharides were prepared. Chito- and β-(1→6)-gluco-oligosaccharides were synthesized by automated glycan assembly (AGA), and α-(1→3)- and α-(1→4)-gluco-oligosaccharides were synthesized in solution using a recently reported highly α-selective glycosylation methodology. Incubation of plants with the synthesized oligosaccharides revealed i) length dependence for plant activation by chito-oligosaccharides and ii) β-1,6-glucan oligosaccharides as a new class of glycans capable of triggering plant activation.

Exploring in vivo multiple sclerosis brain microstructural damage through T1w/T2w ratio: a multicentre study

OBJECTIVES

To evaluate white matter and grey matter T1-weighted (w)/T2w ratio (T1w/T2w ratio) in healthy controls and patients with multiple sclerosis, and its association with clinical disability.

METHODS

In this cross-sectional study, 270 healthy controls and 434 patients with multiple sclerosis were retrospectively selected from 7 European sites. T1w/T2w ratio was obtained from brain T2w and T1w scans after intensity calibration using eyes and temporal muscle.

RESULTS

In healthy controls, T1w/T2w ratio increased until 50-60 years both in white and grey matter. Compared with healthy controls, T1w/T2w ratio was significantly lower in white matter lesions of all multiple sclerosis phenotypes, and in normal-appearing white matter and cortex of patients with relapsing-remitting and secondary progressive multiple sclerosis (p≤0.026), but it was significantly higher in the striatum and pallidum of patients with relapsing-remitting, secondary progressive and primary progressive multiple sclerosis (p≤0.042). In relapse-onset multiple sclerosis, T1w/T2w ratio was significantly lower in white matter lesions and normal-appearing white matter already at Expanded Disability Status Scale (EDSS) <3.0 and in the cortex only for EDSS ≥3.0 (p≤0.023). Conversely, T1w/T2w ratio was significantly higher in the striatum and pallidum for EDSS ≥4.0 (p≤0.005). In primary progressive multiple sclerosis, striatum and pallidum showed significantly higher T1w/T2w ratio beyond EDSS=6.0 (p≤0.001). In multiple sclerosis, longer disease duration, higher EDSS, higher brain lesional volume and lower normalised brain volume were associated with lower lesional and cortical T1w/T2w ratio and a higher T1w/T2w ratio in the striatum and pallidum (β from -1.168 to 0.286, p≤0.040).

CONCLUSIONS

T1w/T2w ratio may represent a clinically relevant marker sensitive to demyelination, neurodegeneration and iron accumulation occurring at the different multiple sclerosis phases.

Lignin Residue-Derived Carbon-Supported Nanoscale Iron Catalyst for the Selective Hydrogenation of Nitroarenes and Aromatic Aldehydes

Heterogeneous iron-based catalysts governing selectivity for the reduction of nitroarenes and aldehydes have received tremendous attention in the arena of catalysis, but relatively less success has been achieved. Herein, we report a green strategy for the facile synthesis of a lignin residue-derived carbon-supported magnetic iron (γ-Fe₂O₃/LRC-700) nanocatalyst. This active nanocatalyst exhibits excellent activity and selectivity for the hydrogenation of nitroarenes to anilines, including pharmaceuticals (e.g., flutamide and nimesulide). Challenging and reducible functionalities such as halogens (e.g., chloro, iodo, and fluoro) and ketone, ester, and amide groups were tolerated. Moreover, biomass-derived aldehyde (e.g., furfural) and other aromatic aldehydes were also effective for the hydrogenation process, often useful in biomedical sciences and other important areas. Before and after the reaction, the γ-Fe₂O₃/LRC-700 nanocatalyst was thoroughly characterized by X-ray diffraction (XRD), N₂ adsorption-desorption, X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), Raman spectroscopy, and thermogravimetric analysis (TGA). Additionally, the γ-Fe₂O₃/LRC-700 nanocatalyst is stable and easily separated using an external magnet and recycled up to five cycles with no substantial drop in the activity. Eventually, sustainable and green credentials for the hydrogenation reactions of 4-nitrobenzamide to 4-aminobenzamide and benzaldehyde to benzyl alcohol were assessed with the help of the CHEM21 green metrics toolkit.

Photoelectrochemical oxidation assisted air purifiers; perspective as potential tools to control indoor SARS-CoV-2 Exposure

Coronavirus diseases 2019 (COVID-19), a viral infection pandemic, arises due to easy human-to-human transmission of severe acute respiratory syndrome coronavirus (SARS-CoV-2). The SARS-CoV-2 causes severe respiratory disorders and other life-threatening diseases (during/post-infection) such as black mold disease, diabetes, cardiovascular, and neurological disorders/diseases. COVID-19 infection emerged challenging to control as SARS-CoV-2 transmits through respiratory droplets (> 10 µm size range), aerosols (< 5 µm), airborne, and particulate matter (PM_1.0 PM_2.5 and PM_10.0). SARS-CoV-2 is more infective in indoor premises due to aerodynamics where droplets, aerosols, and PM_1.0/2.5/10.0 float for a longer time and distance leading to a higher probability of it entering upper and lower respiratory tracts. To avoid human-to-human transmission, it is essential to trap and destroy SARS-CoV-2 from the air and provide virus-free air that will significantly reduce indoor viral exposure concerns. In this process, an efficient nano-enable photoelectrochemical oxidation (PECO, a destructive approach to neutralize bio-organism) assisted air purification is undoubtedly a good technological choice. This technical perspective explores the role of PECO-assisted Air-Purifiers (i.e., Molekule as a focus example for proof-of-concept) to trap and destroy indoor microorganisms (bacteria and viruses including Coronaviruses), molds, and allergens, and other indoor air pollutants, such as volatile organic compounds (VOCs) and PM_1.0/2.5/10.0. It is observed through various standard and non-standard tests that stimuli-responsive nanomaterials coated filter technology traps and destroys microbial particles. Due to technological advancements according to premises requirements and high-performance desired outcomes, Molekule air purifiers, Air Pro Air -Rx, Air Mini, and Air Mini+, have received Food and Drug Administration (FDA) clearance as a Class II medical device for the destruction of bacteria and viruses.

Tuning the structural stability and spin-glass behavior in α-MnO2 nanotubes by Sn ion doping

A series of α-Mn_1-xSn_xO₂ was synthesized by a simple hydrothermal method to shed light on the effect of substitution. Powder X-ray diffraction and scanning electron microscopy indicated that the particle size, crystal structure and morphology of the samples did not change with an increase of the Sn content. Sn, Mn, O and K elements were all uniformly distributed in the particles, which was observed using energy-dispersive X-ray spectroscopy. However, thermogravimetric analysis showed that the structural stability increased, and an increase of the Mn oxidation state from 3.8+ to nearly 4.0+ was observed by X-ray absorption spectroscopy. Besides, ¹¹⁹Sn Mössbauer spectroscopy revealed that the Sn ions are all 4+ and incorporate into the lattice by replacing the Mn ions. The DC and AC magnetic susceptibility measurements down to 2 K exhibited a spin-glass phenomenon, and the freezing temperature, T_f, decreased from 44 K to 30.5 K with increasing Sn content. This indicates that increased disorder by nonmagnetic substitution results in the enhancement of the frustration in the lattice. Meanwhile, with doping of Sn⁴⁺ ions, the Curie-Weiss temperature increased, indicating enhanced antiferromagnetic interaction. Although the mixed valence of Mn³⁺ and Mn⁴⁺ almost disappeared, the reduction of charge disorder did not lead to the magnetic ordering in the sample. Since the Sn⁴⁺ ions are diamagnetic and have the same magnetic effect as cation vacancies in the lattice, so it is reasonable to believe that the spin-glass transition in α-MnO₂ results from the cation vacancies rather than the mixture of Mn³⁺ and Mn⁴⁺.

Evaluation of long-term carbon sequestration of biochar in soil with biogeochemical field model

Return of biomass-derived biochar (BC) into soil has been considered as one of the carbon sequestration (CS) methods. It is important to evaluate the long-term biochar CS potential by integrating the complex physical interferences and biochemical reactions in real soil. This study incorporated biochar into a biogeochemical field model and established a daily-resolution simulator to assess 5-, 50-, 500-year CS potential upon Soil-Biochar-Plant interaction. Through the scenario simulation of burying 7.5-75 t/ha BC-C in a 50 cm-depth rainfed cropland soil with corn planted, we found biochar could retain 483-557 kg C/t BC-C after 500 years' natural decomposition, although soil pedoturbation and plant erosion accelerated its mineralization. Moreover, biochar provided labile-C to compensate microbial decomposition and modified long-term soil climate, resulting in a decrease in soil organic carbon degradation of 44-265 kg C/t BC-C. Furthermore, biochar promoted plant photosynthetic performance by offering exogenous nutrients, equivalent to capturing 66-1039 kg C/t BC-C over 50 years. But biochar limited endogenous nutrient release and inhibited plant growth after exogenous nutrients exhausted, so total CS decreases yearly after reaching an upper limit (1030-1722 kg C/t BC-C). A total of 651-725 kg C/t BC-C could be sequestered after 500 years. And biochar is more potential in infertile and arid soils. Overall, this study indicates the necessity of taking the biogeochemical reactions into consideration to assess biochar long-term CS, and it further demonstrates biochar soil implementation is a prospective carbon-negative strategy.