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The transition metal-catalyzed asymmetric hydrogenation (AH) of ketones to produce enantioenriched alcohols is an important reaction in organic chemistry with applications in the pharmaceutical and agrochemical fields. Using earth-abundant, biorelevant cobalt as the central metal in the catalyst has a high potential to improve sustainability and achieve hydrogenation reactions that are scalable. However, due to the high d-electron count, designing cobalt catalysts that exhibit turnover numbers (TONs, ≥1000) and enantioselectivities (≥90%) sufficient for synthetic utility and practical scalability (≥1 kg scale) remains a challenge. In this work, an efficient catalyst design strategy utilizing an amino(imino)diphosphine Co(II) bromide precatalyst is presented to achieve this goal. The quantitative production of a wide range of secondary chiral alcohols with TONs of up to 150,000 and an enantiomeric excess (e.e.) of up to 99% at a scale of up to 1.35 kg was achieved, indicating that the proposed cobalt catalyst is highly promising for AH and scale-up reactions. A mechanistic study revealed that the synergism of an N-H functionality and a redox-active ligand endows the cobalt catalyst with a high productivity and excellent enantioselectivity.
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Targeted photodynamic therapy (PDT) offers advantages over nontargeted approaches, including improved selectivity, efficacy, and reduced side effects. This study developed star-shaped glycopolymeric photosensitizers using porphyrin-based initiators via ATRP. Incorporating a porphyrin core gave the polymers fluorescence and ROS generation, while adding fructose improved solubility and targeting capabilities. The photosensitizers had high light absorption, singlet oxygen production, specificity, low dark toxicity, and biocompatibility. The glycopolymers with longer sugar arms and higher density showed better uptake on MCF-7 and MDA-MB-468 cells compared to HeLa cells, indicating enhanced targeting capabilities. Inhibition of endocytosis confirmed the importance of the GLUT5 receptor. The resulting polymers exhibited good cytocompatibility under dark conditions and satisfactory PDT under light irradiation. Interestingly, the polymers containing fructose have a GLUT5-dependent elimination effect on the MCF-7 and MDA-MB-468 cells. The intracellular ROS production followed a similar pattern, indicating that the fructose polymer exhibits specific targeting toward cells with GLUT5 receptors.
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Fotoquimioterapia , Porfirinas , Humanos , Fármacos Fotosensibilizantes/farmacología , Fármacos Fotosensibilizantes/uso terapéutico , Fotoquimioterapia/métodos , Células HeLa , Especies Reactivas de Oxígeno , Porfirinas/farmacología , Polímeros/farmacología , Fructosa/farmacologíaRESUMEN
The emergence of photoinduced energy/electron transfer-reversible addition-fragmentation chain transfer polymerization (PET-RAFT) not only revolutionized the field of photopolymerization but also accelerated the development of porphyrin-based photocatalysts and their analogues. The continual expansion of the monomer family compatible with PET-RAFT polymerization enhances the range of light radiation that can be harnessed, providing increased flexibility in polymerization processes. Furthermore, the versatility of PET-RAFT polymerization extends beyond its inherent capabilities, enabling its integration with various technologies in diverse fields. This integration holds considerable promise for the advancement of biomaterials with satisfactory bioapplications. As researchers delve deeper into the possibilities afforded by PET-RAFT polymerization, the collaborative efforts of individuals from diverse disciplines will prove invaluable in unleashing its full potential. This Review presents a concise introduction to the fundamental principles of PET-RAFT, outlines the progress in photocatalyst development, highlights its primary applications, and offers insights for future advancements in this technique, paving the way for exciting innovations and applications.
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Porfirinas , Humanos , Polimerizacion , Tomografía de Emisión de PositronesRESUMEN
This meta-analysis aims to systematically investigate the clinical efficacy of Chinese herbal compound dressings in treating patients with diabetic foot ulcers (DFUs). A comprehensive computerised search was conducted in databases including PubMed, Embase, Google Scholar, Cochrane Library, China National Knowledge Infrastructure, and Wanfang databases, from database inception to November 2023, to identify randomised controlled trials (RCTs) concerning the use of Chinese herbal compound dressings in patients with DFU. Two researchers independently screened the literature, extracted data, and assessed the quality based on inclusion and exclusion criteria. Data analysis was performed using Stata 17.0 software. Overall, 18 RCTs involving 1405 DFU patients were included. The analysis indicated that compared to the control group, the group treated with Chinese herbal compound dressings had significantly shorter ulcer healing time (standardised mean difference [SMD] = -2.49, 95% confidence interval [CI]: -3.53 to -1.46, p < 0.001), reduced ulcer surface area (SMD = -3.38, 95% CI: -4.67 to -2.09, p < 0.001), and higher healing rates (odds ratio [OR] = 2.24, 95% CI: 1.72-2.92, p < 0.001) as well as overall effectiveness rates (OR = 4.56, 95% CI: 3.10-6.71, p < 0.001). This study demonstrates that the external application of Chinese herbal compound dressings in patients with DFU can significantly shorten the ulcer healing time and improve wound healing rates.
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Diabetes Mellitus , Pie Diabético , Humanos , Pueblo Asiatico , Vendajes , China , Análisis de Datos , Pie Diabético/tratamiento farmacológicoRESUMEN
The combination of ring-closing metathesis with betulin enables the design and synthesis of novel biomolecules representing a library of triterpenoid derivatives for potential pharmacological research. In this work, cyclic olefin betulin derivatives were attempted to be prepared by the combination of ring-closing metathesis with betulin. Dicyclohexyl carbodiimide coupling reaction allowed the transformation of betulin into two types of linear olefin derivatives that have different methylene spacer lengths between the olefin and ester groups. Subsequently, betulin-based cycloolefins were synthesized by ring-closing metathesis using Grubbs first-generation catalyst. The influence of different parameters including solvents, temperature, catalysts, and catalyst loading on ring-closing metathesis was investigated. Cytotoxicity results indicated that these betulin-based olefin derivatives, derived from renewable bioresources, have potential applications in the biomedical field.
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Rutenio , Ciclización , Alquenos , CatálisisRESUMEN
Chemically processed methylammonium tin-triiodide (CH3NH3SnI3) films include Sn in different oxidation states, leading to poor stability and low power conversion efficiency of the resulting solar cells (PSCs). The development of absorbers with Sn [2+] only has been identified as one of the critical steps to develop all Sn-based devices. Here, we report on coevaporation of CH3NH3I and SnI2 to obtain absorbers with Sn being only in the preferred oxidation state [+2] as confirmed by X-ray photoelectron spectroscopy. The Sn [4+]-free absorbers exhibit smooth highly crystalline surfaces and photoluminescence measurements corroborating their excellent optoelectronic properties. The films show very good stability under heat and light. Photoluminescence quantum yields up to 4 × 10-3 translate in a quasi Fermi-level splittings exceeding 850 meV under one sun equivalent conditions showing high promise in developing lead-free, high efficiency, and stable PSCs.
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Flower color is one of the crucial traits of ornamental plants. Rhododendron delavayi Franch. is a famous ornamental plant species distributed in the mountain areas of Southwest China. This plant has red inflorescence and young branchlets. However, the molecular basis of the color formation of R. delavayi is unclear. In this study, 184 MYB genes were identified based on the released genome of R. delavayi. These genes included 78 1R-MYB, 101 R2R3-MYB, 4 3R-MYB, and 1 4R-MYB. The MYBs were divided into 35 subgroups using phylogenetic analysis of the MYBs of Arabidopsis thaliana. The members of the same subgroup in R. delavayi had similar conserved domains and motifs, gene structures, and promoter cis-acting elements, which indicate their relatively conserved function. In addition, transcriptome based on unique molecular identifier strategy and color difference of the spotted petals, unspotted petals, spotted throat, unspotted throat, and branchlet cortex were detected. Results showed significant differences in the expression levels of R2R3-MYB genes. Weighted co-expression network analysis between transcriptome and chromatic aberration values of five types of red samples showed that the MYBs were the most important TFs involved in the color formation, of which seven were R2R3-MYB, and three were 1R-MYB. Two R2R3-MYB (DUH019226.1 and DUH019400.1) had the highest connectivity in the whole regulation network, and they were identified as hub genes for red color formation. These two MYB hub genes provide references for the study of transcriptional regulation of the red color formation of R. delavayi.
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Arabidopsis , Rhododendron , Factores de Transcripción/metabolismo , Genes myb , Filogenia , Proteínas de Plantas/genética , Arabidopsis/genética , Regulación de la Expresión Génica de las PlantasRESUMEN
OBJECTIVE: Polymorphisms of T cell immunoglobulin and mucin domain-containing molecule 3 (TIM-3) were reported to be associated with cancer risk and patients' survival. This study aims to investigate the correlation of TIM-3 polymorphisms with susceptibility to epithelial ovarian cancer (EOC) and patients' outcomes. METHODS: A total of 700 EOC patients and 710 healthy controls from North China were included. The polymorphisms (rs10053538, rs10515746 and rs1036199) were genotyped using the polymerase chain reaction/ligase detection reaction (PCR-LDR) method. Survival data were available for 339 patients after cytoreductive surgery. The expression level of TIM-3 was detected by real-time quantitative PCR (RT-qPCR). The prognostic value of TIM3 in EOC patients was assessed using the Kaplan-Meier plotter database. RESULTS: The results showed that none of the TIM3 polymorphisms were associated with the risk of developing EOC. Patients with the rs10053538 CA + AA genotype had worse PFS and OS than those with the CC genotype (HR = 1.49, 95% CI = 1.05-2.09, P = 0.024 and HR = 1.57, 95%CI = 1.09-2.26, P = 0.017, respectively). The RT-qPCR results showed that the expression levels of TIM-3 mRNA in EOC tissues with the rs10053538CA + AA genotypes were significantly higher than those with the CC genotype (P = 0.006). Analysis using the Kaplan-Meier plotter database showed that high expression of TIM-3 mRNA was significantly associated with shorter PFS and OS in EOC patients (HR = 1.57, 95%CI = 1.29-1.91, P < 0.001 and HR = 1.31, 95% CI = 1.06-1.63, P = 0.013, respectively). CONCLUSIONS: TIM-3 polymorphisms were not associated with risk of developing EOC. Both rs10053538 and the expression level of TIM-3 mRNA may be associated with its clinical outcome in EOC patients.
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Carcinoma Epitelial de Ovario/genética , Procedimientos Quirúrgicos de Citorreducción , Receptor 2 Celular del Virus de la Hepatitis A/genética , Recurrencia Local de Neoplasia/epidemiología , Neoplasias Ováricas/genética , Adulto , Anciano , Anciano de 80 o más Años , Carcinoma Epitelial de Ovario/diagnóstico , Carcinoma Epitelial de Ovario/mortalidad , Carcinoma Epitelial de Ovario/cirugía , Estudios de Casos y Controles , China/epidemiología , Supervivencia sin Enfermedad , Femenino , Estudios de Seguimiento , Regulación Neoplásica de la Expresión Génica , Predisposición Genética a la Enfermedad , Humanos , Estimación de Kaplan-Meier , Persona de Mediana Edad , Recurrencia Local de Neoplasia/genética , Neoplasias Ováricas/diagnóstico , Neoplasias Ováricas/mortalidad , Neoplasias Ováricas/cirugía , Ovario/patología , Ovario/cirugía , Polimorfismo de Nucleótido Simple , Pronóstico , Supervivencia sin Progresión , Regulación hacia Arriba , Adulto JovenRESUMEN
Diphosphine ligands that merge both axial and P-centered chirality may exhibit superior or unique properties. Herein we report the diastereoselective introduction of P-centered chirality at the 2-position of the axially chiral 2'-(phosphine oxide)-1,1'-binaphthyl scaffold. A lithium-bromide exchange reaction of a 2-bromo-2'-(phosphine oxide)-1,1'-binaphthyl and treatment with dichlorophosphines followed by a nucleophilic organometallic reagent afforded unsymmetrical 2-phosphino-2'-(phosphine oxide)-1,1'-binaphthyls with binaphthyl axial chirality and one or two phosphorus stereocenters with a variety of Pâ substituents. The final diastereomerically pure 2,2'-bisphosphino-1,1'-binaphthyls were obtained by reduction of the phosphine oxide directing group. Preliminary results demonstrated that a ligand with this hybrid chirality could induce higher stereoselectivity in the metal-complex-catalyzed asymmetric hydrogenation of a dialkyl ketone.
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A simple and sensitive gas sensor was proposed for the determination of 1,2-propylene oxide (PO) based on its cataluminescence (CTL) by oxidation in the air on the surface of CeO2 nanoparticles. The luminescence characteristics and optimal conditions were investigated in detail. Under optimized conditions, the linear range of the CTL intensity versus the concentration of PO was 10-150 ppm, with a correlation coefficient (r) of 0.9974 and a limit of detection (S/N = 3) of 0.9 ppm. The relative standard deviation for 40 ppm PO was 1.2% (n = 7). There was no or only weak response to common foreign substances including acetone, formaldehyde, ethyl acetate, acetic acid, chloroform, propanol, carbon tetrachloride, ether and methanol. There was no significant change in the catalytic activity of the sensor for 100 h. The proposed method was simple and sensitive, with a potential of detecting PO in the environment and industry.
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Cerio/química , Compuestos Epoxi/análisis , Mediciones Luminiscentes/métodos , Nanopartículas/química , Aire , Catálisis , Límite de Detección , Mediciones Luminiscentes/instrumentación , Microscopía Electrónica de Transmisión , Temperatura , Difracción de Rayos XRESUMEN
Rhododendron delavayi, a notable ornamental plant primarily found in regions of China like Yunnan and Guizhou provinces, holds substantial horticultural value. To elucidate the systematic phylogenetic relationships and organelle genomic differences within R. delavayi and related Rhododendron species, we conducted sequencing and assembly of the complete mitochondrial genome of R. delavayi. The full-length mitochondrial genome of it was a singular circular molecule spanning 1,009,263 bp, comprising 53 protein-coding genes, including 18 transfer RNA (tRNA) genes, 3 ribosomal RNA (rRNA) genes, and 32 protein-coding genes. A total of 1,182 simple sequence repeats (SSRs) loci were identified in the R. delavayi mitochondrial genome, primarily consisting of single nucleotide, dinucleotide, and trinucleotide repeats. Nucleotide diversity analysis highlighted five genes (atp6, atp9, cox2, nad1, and rpl10) with the highest diversity within the mitochondrial genomes of Rhododendron genus. Comparative analysis of the mitochondrial genome of R. delavayi with those of four other Rhododendron species indicated complex rearrangements in 21 genes, including rps4, nad6, rps3, atp6, cob, atp9, nad7, among others. The mitochondrial phylogenetic tree revealed a close relationship between R. delavayi and R. decorum, forming a sister clade to R. × pulchrum and R. simsii. Furthermore, 126 plastid-to-mitochondrial gene transfers in R. delavayi were identified, ranging from 30 bp to 19,385 bp. These fragments collectively constituted 47.54 % and 9.52 % of the chloroplast and mitochondrial genomes (202,169 bp), respectively. Complex mitochondrial-to-mitochondrial transfers were also observed, with 843 identified fragments totaling 312,036 bp (30.92 % of the mitochondrial genome). Segments exceeding 10 kb may mediate homologous recombination within the mitochondrial molecules. Remarkably, our study underscores that the mitochondrial genome of R. delavayi was the largest reported within the Rhododendron genus to date. The intricate rearrangements observed in the mitochondrial genomes of Rhododendron species, alone with the identification of five potential molecular marker sites, provided valuable insights for species classification and parentage identification within the Rhododendron genus.
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Genoma Mitocondrial , Filogenia , Rhododendron , Rhododendron/genética , Rhododendron/clasificación , Repeticiones de Microsatélite/genética , ARN de Transferencia/genética , Variación GenéticaRESUMEN
Tin halide perovskites are an appealing alternative to lead perovskites. However, owing to the lower redox potential of Sn(II)/Sn(IV), particularly under the presence of oxygen and water, the accumulation of Sn(IV) at the surface layer will negatively impact the device's performance and stability. To this end, this work has introduced a novel multifunctional molecule, 1,4-phenyldimethylammonium dibromide diamine (phDMADBr), to form a protective layer on the surface of Sn-based perovskite films. Strong interactions between phDMADBr and the perovskite surface improve electron transfer, passivating uncoordinated Sn(II), and fortify against water and oxygen. In situ grazing incidence wide-angle X-ray scattering (GIWAXS) analysis confirms the enhanced thermal stability of the quasi-2D phase, and hence the overall enhanced stability of the perovskite. Long-term stability in devices is achieved, retaining over 90% of the original efficiency for more than 200 hours in a 10% RH moisture N2 environment. These findings propose a new approach to enhance the operational stability of Sn-based perovskite devices, offering a strategy in advancing lead-free optoelectronic applications.
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OBJECTIVE: To investigate the prevalence of Capillaria hepatica in rodents from Anning Prefecture, Yunnan, and observe the susceptibility of C. hepatica to SD rats and KM mice. METHODS: Rodents were trapped in a cultivated filed of Wenquan Town, Annning from March 2010 to March 2012. The species of rodents were identified. The liver was examined and a microscopic examination of tissue was performed by the tissue press technique for the presence of the typical bipolar eggs, adults or larval stages. The prevalence of C. hepatica in rodents was calculated. C. hepatica eggs were collected and cultured in vitro. Each SD rat or KM mouse was orally infected with approximately 1 000 C. hepatica eggs. The control groups with 4 SD rats or 4 KM mice received only normal saline. The experimental animals were euthanized at the 30th and 80th day post infection. Collected liver samples were processed for gross pathological and histological section examination. RESULTS: A total of 115 rodents were captured and examined. C. hepatica eggs were found in 26 (22.6%) rodents. There was no significant difference in the prevalence between female (22.5%, 18/80) and males (22.9%, 26/115) (P > 0.05). The highest prevalence was found in Rattus norvegicus (10/11). Pathologi cal findings showed numerous white-yellow small nodules ranged from 0.1-0.2 cm in diameter. Under light microscope, C. hepatica eggs were ovoid [(50-65) microm x (25-30) microm]. At the 30th day post-infection, there were several adult worms and their eggs delimited by a fibrous capsule, and septal fibrosis formations occurred in the liver of SD rat. No worm or eggs were found in the mouse liver, but the liver presented inflammatory cell infiltration. At the 80th day post-infection, live worms disappeared from the focal lesions in the liver of SD rat, being replaced by partially calcified worm debris. Mature worms and eggs were seen in the KM mouse liver, however, septal fibrosis was absent. CONCLUSION: This study has documented a high prevalence of C. hepaticum in R. norvegicus from Anning Prefecture. SD rat and KM mouse are the susceptible hosts of C. hepatica.
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Infecciones por Enoplida/epidemiología , Interacciones Huésped-Parásitos , Parasitosis Hepáticas/epidemiología , Roedores/parasitología , Animales , Capillaria , China/epidemiología , Femenino , Hígado/parasitología , Parasitosis Hepáticas/parasitología , Masculino , Ratones , Ratones Endogámicos , Ratas , Ratas Sprague-DawleyRESUMEN
Plant-derived biocompounds play a crucial role in the field of renewable materials due to their sustainability as they can be converted into monomers for polymerization, comparable to numerous monomers obtained from petroleum. In this work, betulin, a triterpene derivative with antibacterial properties obtained from birch tree bark, was esterified to produce two varieties of α,ω-diene derivatives with different lengths of methylene spacers. These derivatives were then copolymerized with 2,2'-(ethylenedioxy)diethanethiol using thiol-ene photopolymerization. We optimized and confirmed the polymerization parameters such as solvents, catalysts, and monomer concentrations. These analyses allowed for the obtainment of polysulfides with a high molar mass of up to 38.9 kg/mol under the optimized conditions. Furthermore, the polysulfides were converted into polysulfoxides by using a dilute hydrogen peroxide solution. Thermal analysis of the obtained polymers revealed excellent thermal stability (up to 300 °C) and tunable glass transition temperatures depending on their molar mass and composition. We successfully produced fibers with a diameter of approximately 3.9 µm by using the electrospinning technique. The morphology and hydrophobicity of the fibers were analyzed by using scanning electron microscopy and water contact angle analysis. Plant-derived polymeric fibers exhibited good cellular biocompatibility and broad-spectrum antibacterial activity, making them promising candidates for applications in fruit preservation.
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Frutas , Triterpenos , Polímeros , Antibacterianos/farmacologíaRESUMEN
Objective: To evaluate the effects of two genetic variants in the promoter of the miR-143/145 cluster on the risk of epithelial ovarian cancer (EOC) and the prognosis of EOC patients. Study design: Genotypes were determined by the polymerase chain reaction and ligase detection reaction method in 563 EOC patients and 576 healthy women. The expression of miR-143 and miR-145 were detected by quantitative real-time polymerase chain reaction (qRT-PCR) in fifty-two EOC tissues. Results: The rs4705342 CC genotype frequencies in EOC patients were higher than those in the controls (P = 0.014). Furthermore, the CC genotype of rs4705342 was associated with an advanced FIGO stage of EOC patients (P = 0.046). Patients with the rs4705342 CC genotype had shorter progression-free survival (PFS) and overall survival (OS) times than those carrying the TT genotype in multivariable analysis adjusting for clinical variables (HR = 1.30, 95% CI = 1.04-1.62, P = 0.020; HR = 1.33, 95% CI = 1.05-1.70, P = 0.020). In addition, the miR-145 levels were lower in EOC tissues with the rs4705342 CC genotype than in those with the TT genotype (P = 0.005). Conclusion: The CC genotype of rs4705342 was related to an increased risk of EOC and poor prognosis of EOC patients, and rs4705342 may serve as a molecular marker for predicting the development of EOC and the clinical outcome of EOC patients.
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Sophora moorcroftiana is a leguminous plant endemic to the Qinghai-Tibet Plateau. It has excellent abiotic stress tolerance and is considered an ideal species for local ecological restoration. However, the lack of genetic diversity in the seed traits of S. moorcroftiana hinders its conservation and utilization on the plateau. Therefore, in this study, genotypic variation and phenotypic correlations were estimated for nine seed traits among 15 accessions of S. moorcroftiana over two years, 2014 and 2019, respectively from 15 sample points. All traits evaluated showed significant (P< 0.05) genotypic variation. In 2014, accession mean repeatability was high for seed perimeter, length, width, and thickness, and 100-seed weight. In 2019, mean repeatability for seed perimeter and thickness, and 100-seed weight were high. The estimates of mean repeatability for seed traits across the two years ranged from 0.382 for seed length to 0.781 for seed thickness. Pattern analysis showed that 100-seed weight was significantly positively correlated with traits such as seed perimeter, length, width, and thickness, and identified populations with breeding pool potential. In the biplot, principal components 1 and 2 explained 55.22% and 26.72% of the total variation in seed traits, respectively. These accessions could produce breeding populations for recurrent selection to develop S. moorcroftiana varieties suitable for restoring the fragile ecological environment of the Qinghai-Tibet Plateau.
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A series of N-(2-(diphenylphosphino)ethyl)-2-alkyl-5,6,7,8-tetrahydroquinolin-8-amines was prepared and used in individually reacting with iron chloride under nitrogen atmosphere to form their iron(ii) complexes Fe1-Fe6. All compounds were characterized using FT-IR spectroscopy and elemental analyses, the organic compounds were confirmed with NMR measurements, and the iron complexes were submitted to single-crystal X-ray diffraction, revealing Fe1, Fe2, Fe4, Fe5, and Fe6 as either mono- or di-nuclear forms. Forming a binary system in situ with two equivalents of LiCH2SiMe3, all iron complexes Fe1-Fe6 efficiently initiated the ring opening polymerization of ε-caprolactone, achieving the TOF up to 8.8 × 103 h-1. More importantly, the resultant polycaprolactone (PCL) possessed high molecular weights with the Mn range of 9.21-24.3 × 104 g mol-1, being a rare case of the iron(ii) catalyst in producing PCL with such high molecular weight. The 1H NMR and MALDI-TOF investigations demonstrated that the PCLs were linear features capped with a methoxy group or CH2SiMe3 or cyclic structure that varied with the molar ratio of [ε-CL]/Fe.
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[This corrects the article DOI: 10.3389/fonc.2022.931445.].
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Interfaces in perovskite solar cells play a crucial role in their overall performance, and therefore, detailed fundamental studies are needed for a better understanding. In the case of the classical n-i-p architecture, TiO2 is one of the most used electron-selective layers and can induce chemical reactions that influence the performance of the overall device stack. The interfacial properties at the TiO2/perovskite interface are often neglected, owing to the difficulty in accessing this interface. Here, we use X-rays of variable energies to study the interface of (compact and mesoporous) TiO2/perovskite in such a n-i-p architecture. The X-ray photoelectron spectroscopy and X-ray absorption spectroscopy methods show that the defect states present in the TiO2 layer are passivated by a chemical interaction of the perovskite precursor solution during the formation of the perovskite layer and form an organic layer at the interface. Such passivation of intrinsic defects in TiO2 removes charge recombination centers and shifts the bands upward. Therefore, interface defect passivation by oxidation of Ti3+ states, the organic cation layer, and an upward band bending at the TiO2/perovskite interface explain the origin of an improved electron extraction and hole-blocking nature of TiO2 in the n-i-p perovskite solar cells.
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The most efficient and stable perovskite solar cells (PSCs) are made from a complex mixture of precursors. Typically, to then form a thin film, an extreme oversaturation of the perovskite precursor is initiated to trigger nucleation sites, e.g., by vacuum, an airstream, or a so-called antisolvent. Unfortunately, most oversaturation triggers do not expel the lingering (and highly coordinating) dimethyl sulfoxide (DMSO), which is used as a precursor solvent, from the thin films; this detrimentally affects long-term stability. In this work, (the green) dimethyl sulfide (DMS) is introduced as a novel nucleation trigger for perovskite films combining, uniquely, high coordination and high vapor pressure. This gives DMS a universal scope: DMS replaces other solvents by coordinating more strongly and removes itself once the film formation is finished. To demonstrate this novel coordination chemistry approach, MAPbI3 PSCs are processed, typically dissolved in hard-to-remove (and green) DMSO achieving 21.6% efficiency, among the highest reported efficiencies for this system. To confirm the universality of the strategy, DMS is tested for FAPbI3 as another composition, which shows higher efficiency of 23.5% compared to 20.9% for a device fabricated with chlorobenzene. This work provides a universal strategy to control perovskite crystallization using coordination chemistry, heralding the revival of perovskite compositions with pure DMSO.