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1.
Molecules ; 29(5)2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38474620

RESUMEN

Hyperlipidemia, characterized by elevated serum lipid concentrations resulting from lipid metabolism dysfunction, represents a prevalent global health concern. Ginsenoside Rb1, compound K (CK), and 20(S)-protopanaxadiol (PPD), bioactive constituents derived from Panax ginseng, have shown promise in mitigating lipid metabolism disorders. However, the comparative efficacy and underlying mechanisms of these compounds in hyperlipidemia prevention remain inadequately explored. This study investigates the impact of ginsenoside Rb1, CK, and PPD supplementation on hyperlipidemia in rats induced by a high-fat diet. Our findings demonstrate that ginsenoside Rb1 significantly decreased body weight and body weight gain, ameliorated hepatic steatosis, and improved dyslipidemia in HFD-fed rats, outperforming CK and PPD. Moreover, ginsenoside Rb1, CK, and PPD distinctly modified gut microbiota composition and function. Ginsenoside Rb1 increased the relative abundance of Blautia and Eubacterium, while PPD elevated Akkermansia levels. Both CK and PPD increased Prevotella and Bacteroides, whereas Clostridium-sensu-stricto and Lactobacillus were reduced following treatment with all three compounds. Notably, only ginsenoside Rb1 enhanced lipid metabolism by modulating the PPARγ/ACC/FAS signaling pathway and promoting fatty acid ß-oxidation. Additionally, all three ginsenosides markedly improved bile acid enterohepatic circulation via the FXR/CYP7A1 pathway, reducing hepatic and serum total bile acids and modulating bile acid pool composition by decreasing primary/unconjugated bile acids (CA, CDCA, and ß-MCA) and increasing conjugated bile acids (TCDCA, GCDCA, GDCA, and TUDCA), correlated with gut microbiota changes. In conclusion, our results suggest that ginsenoside Rb1, CK, and PPD supplementation offer promising prebiotic interventions for managing HFD-induced hyperlipidemia in rats, with ginsenoside Rb1 demonstrating superior efficacy.


Asunto(s)
Microbioma Gastrointestinal , Ginsenósidos , Hiperlipidemias , Sapogeninas , Ratas , Animales , Ginsenósidos/metabolismo , Dieta Alta en Grasa , Metabolismo de los Lípidos , Peso Corporal , Ácidos y Sales Biliares
2.
Proc Natl Acad Sci U S A ; 121(10): e2310409121, 2024 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-38427603

RESUMEN

Ovarian immature teratomas (OITs) are malignant tumors originating from the ovarian germ cells that mainly occur during the first 30 y of a female's life. Early age of onset strongly suggests the presence of susceptibility gene mutations for the disease yet to be discovered. Whole exon sequencing was used to screen pathogenic mutations from pedigrees with OITs. A rare missense germline mutation (C262T) in the first exon of the BMP15 gene was identified. In silico calculation suggested that the mutation could impair the formation of mature peptides. In vitro experiments on cell lines confirmed that the mutation caused an 84.7% reduction in the secretion of mature BMP15. Clinical samples from OIT patients also showed a similar pattern of decrease in the BMP15 expression. In the transgenic mouse model, the spontaneous parthenogenetic activation significantly increased in oocytes carrying the T allele. Remarkably, a mouse carrying the T allele developed the phenotype of OIT. Oocyte-specific RNA sequencing revealed that abnormal activation of the H-Ras/MAPK pathway might contribute to the development of OIT. BMP15 was identified as a pathogenic gene for OIT which improved our understanding of the etiology of OIT and provided a potential biomarker for genetic screening of this disorder.


Asunto(s)
Mutación Missense , Teratoma , Humanos , Femenino , Ratones , Animales , Mutación de Línea Germinal , Oocitos/fisiología , Ovario , Proteína Morfogenética Ósea 15/genética , Teratoma/genética
3.
J Org Chem ; 89(3): 1719-1726, 2024 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-38204281

RESUMEN

As an interim paradigm for the catalysts between those based on more conventional mononuclear molecular Pd complexes and Pdn nanoparticles widely used in organic synthesis, polynuclear palladium clusters have attracted great attention for their unique reactivity and electronic properties. However, the development of Pd cluster catalysts for organic transformations and mechanistic investigations is still largely unexploited. Herein, we disclose the use of trinuclear palladium (Pd3Cl) species as an active catalyst for the direct C-H α-arylation of benzo[b]furans with aryl iodides to afford 2-arylbenzofurans in good yields under mild conditions. With this method, broad substrate adaptability was observed, and several drug intermediates were synthesized in high yields. Mechanistic studies indicated that the Pd3 core most likely remained intact throughout the reaction course.

4.
Angew Chem Int Ed Engl ; 63(12): e202317995, 2024 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-38191987

RESUMEN

Exploiting emissive hydrophobic nanoclusters for hydrophilic applications remains a challenge because of photoluminescence (PL) quenching during phase transfer. In addition, the mechanism underlying PL quenching remains unclear. In this study, the PL-quenching mechanism was examined by analyzing the atomically precise structures and optical properties of a surface-engineered Ag29 nanocluster with an all-around-carboxyl-functionalized surface. Specifically, phase-transfer-triggered PL quenching was justified as molecular decoupling, which directed an unfixed cluster surface and weakened the radiative transition. Furthermore, emission recovery of the quenched nanoclusters was accomplished by using a supramolecular recoupling approach through the glutathione-addition-induced aggregation of cluster molecules, wherein the restriction of intracluster motion and intercluster rotation strengthened the radiative transition of the clusters. The results of this work offer a new perspective on structure-emission correlations for atomically precise nanoclusters and hopefully provide insight into the fabrication of highly emissive cluster-based nanomaterials for downstream hydrophilic applications.

5.
ACS Nano ; 18(2): 1555-1562, 2024 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-38166168

RESUMEN

Studying the interactions of atomically precise metal nanoclusters in their assembly systems is of great significance in the nanomaterial research field, which has attracted increasing interest in the last few decades. Herein, we report the cocrystallization of two oppositely charged atomically precise metal nanoclusters in one unit cell: [Au1Ag24(SR)18]- ((AuAg)25 for short) and [AuxAg27-x(Dppf)4(SR)9]2+ (x = 10-12; (AuAg)27 for short) with a 1:1 ratio. (AuAg)27 could maintain its structure in the presence of (AuAg)25, whether in the crystalline and the solution state, while the metastable (AuAg)27 component underwent a spontaneous transformation to (AuAg)16(Dppf)2(SR)8 after dissociating the (AuAg)25 component from this cocrystal, demonstrating the "parasitism" relationship of the (AuAg)27 component over (AuAg)25 in this dual-cluster system. This work enriches the family of cluster-based assemblies and elucidates the delicate relationship between nanoparticles of cocrystals.

6.
Nanoscale ; 16(3): 1254-1259, 2024 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-38117189

RESUMEN

The preparation and structural determination of silver nanoclusters (especially the medium-sized Ag clusters) remain more challenging relative to those of their gold counterparts because of the comparative instability of the former. In this work, three medium-sized Ag clusters were controllably synthesized and structurally determined, namely, [Ag52(S-Adm)30Br4H20]2- (Ag52 for short), Ag54(S-Adm)30Br4H20 (Ag54 for short), and [Ag58(S-Adm)30Br4(NO3)2H22]2+ (Ag58 for short) nanoclusters. Specifically, the introduction of PPh4Br gave rise to the generation of Ag52 and Ag54 nanoclusters with homologous compositions and configurations, while the TOABr salt selected Ag58 as the sole cluster product, whose geometric structure was completely different from those of Ag52 and Ag54 nanoclusters. In addition, the optical absorptions and emissions of the three medium-sized silver nanoclusters were compared. The findings in this work not only provide three uniquely medium-sized nanoclusters to enrich the silver cluster family but also point out a new approach (i.e., changing the counterion salt) for the preparation of new nanoclusters with novel structures.

7.
Sensors (Basel) ; 23(23)2023 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-38067779

RESUMEN

Modern embedded systems have achieved relatively high processing power. They can be used for edge computing and computer vision, where data are collected and processed locally, without the need for network communication for decision-making and data analysis purposes. Face detection, face recognition, and pose detection algorithms can be executed with acceptable performance on embedded systems and are used for home security and monitoring. However, popular machine learning frameworks, such as MediaPipe, require relatively high usage of CPU while running, even when idle with no subject in the scene. Combined with the still present false detections, this wastes CPU time, elevates the power consumption and overall system temperature, and generates unnecessary data. In this study, a low-cost low-resolution infrared thermal sensor array was used to control the execution of MediaPipe's pose detection algorithm using single-board computers, which only runs when the thermal camera detects a possible subject in its field of view. A lightweight algorithm with several filtering layers was developed, which allowed the effective detection and isolation of a person in the thermal image. The resulting hybrid computer vision proved effective in reducing the average CPU workload, especially in environments with low activity, almost eliminating MediaPipe's false detections, and reaching up to 30% power saving in the best-case scenario.


Asunto(s)
Algoritmos , Carga de Trabajo , Humanos , Computadores , Aprendizaje Automático
8.
Hereditas ; 160(1): 37, 2023 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-37978541

RESUMEN

Interstitial lung diseases (ILDs), or diffuse pulmonary lung disease, are a subset of lung diseases that primarily affect lung alveoli and the space around interstitial tissue and bronchioles. It clinically manifests as progressive dyspnea, and patients often exhibit a varied decrease in pulmonary diffusion function. Recently, variants in telomere biology-related genes have been identified as genetic lesions of ILDs. Here, we enrolled 82 patients with interstitial pneumonia from 2017 to 2021 in our hospital to explore the candidate gene mutations of these patients via whole-exome sequencing. After data filtering, a novel heterozygous mutation (NM_025099: p.Gly131Arg) of CTC1 was identified in two affected family members. As a component of CST (CTC1-STN1-TEN1) complex, CTC1 is responsible for maintaining telomeric structure integrity and has also been identified as a candidate gene for IPF, a special kind of chronic ILD with insidious onset. Simultaneously, real-time PCR revealed that two affected family members presented with short telomere lengths, which further confirmed the effect of the mutation in the CTC1 gene. Our study not only expanded the mutation spectrum of CTC1 and provided epidemiological data on ILDs caused by CTC1 mutations but also further confirmed the relationship between heterozygous mutations in CTC1 and ILDs, which may further contribute to understanding the mechanisms underlying ILDs.


Asunto(s)
Enfermedades Pulmonares Intersticiales , Acortamiento del Telómero , Humanos , Proteínas de Unión a Telómeros/genética , Proteínas de Unión a Telómeros/metabolismo , Pueblos del Este de Asia , Mutación , Enfermedades Pulmonares Intersticiales/genética , Telómero/genética
9.
Front Oncol ; 13: 1276907, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38023214

RESUMEN

Tertiary lymphoid structures (TLSs), referred to as tertiary lymphoid organs and lymphoid tissue neogenesis, are aggregates of immune cells that occur in nonlymphoid tissues. In recent years, it has been found that TLSs within the tumor microenvironment have been associated with local adaptive immune immunity against cancer and favorable prognosis in several human solid tumors, including gynecological cancers. The issue of the prognosis of gynecological cancers, including endometrial, cervical, and ovarian cancer, is an enormous challenge that many clinical doctors and researchers are now facing. Concerning the predictive prognostic role of TLSs, effective evaluation, and quantification of TLSs in human tissues may be used to assist gynecologists in assessing the clinical outcome of gynecological cancer patients. This review summarizes the current knowledge of TLSs in gynecological cancers, mainly focusing on the potential mechanism of TLS neogenesis, methods for evaluating TLSs, their prognostic value, and their role in antitumor immune immunity. This review also discusses the new therapeutic methods currently being explored in gynecological cancers to induce the formation of TLSs.

10.
Nanoscale ; 15(36): 14941-14948, 2023 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-37655628

RESUMEN

Although several silver-based nanoclusters have been controllably prepared and structurally determined, their electrochemical catalytic performances have been relatively unexplored (or showed relatively weak ability towards electro-catalysis). In this work, we accomplished the step-by-step enhancement of the electrocatalytic hydrogen evolution reaction (HER) efficiency based on an Ag29 cluster template. A combination of atomically precise operations, including the kernel alloying, ligand engineering, and surface activation, was exploited to produce a highly efficient Pt1Ag28-BTT-Mn(10) nano-catalyst towards HER, derived from both experimental characterization and theoretical modelling. The precision characteristic of the Ag29-based cluster system enables us to understanding the correlations between nanocluster structures and HER performances at the atomic level. Overall, the findings of this work will hopefully provide more opportunities for the customization of new cluster-based nano-catalysts with enhanced electrocatalytic capacities.

11.
Chem Sci ; 14(32): 8474-8482, 2023 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-37592984

RESUMEN

The restriction of intramolecular rotation has been extensively exploited to trigger the property enhancement of nanocluster-based materials. However, such a restriction is induced mainly by intermolecular aggregation. The direct restriction of intramolecular rotation of metal nanoclusters, which could boost their properties at the single molecular level, remains rarely explored. Here, ligand engineering was applied to activate intramolecular interactions at the interface between peripheral ligands and metallic kernels of metal nanoclusters. For the newly reported Au4Ag13(SPhCl2)9(DPPM)3 nanocluster, the molecule-level interactions between the Cl terminals on thiol ligands and the Ag atoms on the cluster kernel remarkably restricted the intramolecular rotation, endowing this robust nanocluster with superior thermal stability, emission intensity, and non-linear optical properties over its cluster analogue. This work presents a novel case of the restriction of intramolecular rotation (i.e., intramolecular interaction-induced property enhancement) for functionalizing metal clusters at the single molecular level.

12.
Chem Soc Rev ; 52(17): 5892-5967, 2023 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-37577838

RESUMEN

Metal nanoclusters serve as an emerging class of modular nanomaterials. The transformation of metal nanoclusters has been fully reflected in their studies from every aspect, including the structural evolution analysis, physicochemical property regulation, and practical application promotion. In this review, we highlight the driving forces for transforming atomically precise metal nanoclusters and summarize the related transforming principles and fundamentals. Several driving forces for transforming nanoclusters are meticulously reviewed herein: ligand-exchange-induced transformations, metal-exchange-induced transformations, intercluster reactions, photochemical transformations, oxidation/reduction-induced transformations, and other factors (intrinsic instability, pH, temperature, and metal salts) triggering transformations. The exploitation of transforming principles to customize the preparations, structures, physicochemical properties, and practical applications of metal nanoclusters is also disclosed. At the end of this review, we provide our perspectives and highlight the challenges remaining for future research on the transformation of metal nanoclusters. Our intended audience is the broader scientific community interested in metal nanoclusters, and we believe that this review will provide researchers with a comprehensive synthetic toolbox and insights on the research fundamentals needed to realize more cluster-based nanomaterials with customized compositions, structures, and properties.

13.
Nanoscale ; 15(33): 13784-13789, 2023 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-37578144

RESUMEN

The determination of surface-active sites in metal nanoclusters is of great significance for the in-depth understanding of structural evolutions and physicochemical property mechanisms. In this work, the surface-active sites of the Au5Ag11(DMBT)8(DPPOE)2 cluster template towards metal-/ligand-exchange reactions were unambiguously identified at the atomic level. The active-site tailoring of this nanocluster gave rise to three derivative nanoclusters, Au5Ag9Cu2(DMBT)8(DPPOE)2, Au5Ag11(DMBT)6(DCBT)2(DPPOE)2, and Au5Ag11(DCBT)8(DPPOE)2. The single-crystal structural analysis revealed that all these M16 (M = Au/Ag/Cu) clusters exhibited almost the same framework. Besides, the surface-active site tailoring contributed to significant changes in optical absorptions and emissions of these metal nanoclusters. The findings in this work not only provide an in-depth understanding of the active-site tailoring of cluster surface structures but also develop an intriguing template that enables us to grasp the structure-property correlations at the atomic level.

14.
Arch Med Sci ; 19(4): 1145-1150, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37560732

RESUMEN

Introduction: The aim was to observe the effect of Toll-like receptor 4 (TLR4) deficiency on clinical severity and expression of Th1/Th2/Th17-associated cytokines in experimental autoimmune neuritis (EAN). Material and methods: We selected C57BL/10 wild type (WT) mice and TLR4 knockout (KO) mice with the C57BL/10 background for induction of the EAN model by immunizing mice twice (days 0 and 8) via subcutaneous injection of 180 µg P0 peptide 180-199 emulsion in 25 µl of PBS and 0.5 mg Mycobacterium tuberculosis (Difco, USA) in 25 µl of Freund's incomplete adjuvant into the back of mice. The concentrations of serum cytokines (IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ and TNF) were determined using the Ms Th1/Th2/Th17 CBA kit. Results: We found that TLR4 deficiency could attenuate the clinical severity and delay the onset of EAN. Moreover, our data showed that the sera levels of IFN-γ, TNF, IL-6 and IL-17A were elevated in the WT mice with EAN when compared with the naive WT mice, but only the production of IL-17A was significantly lower in the TLR4 KO mice with EAN than in their WT counterparts. Conclusions: Based on these findings, TLR4 may contribute to the pathogenesis of EAN by regulating Th17 cells and the production of Th17-associated factors. However, the exact mechanism remains unclear and more evidence is needed to elucidate its role in EAN.

15.
J Am Chem Soc ; 145(25): 13750-13757, 2023 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-37253153

RESUMEN

Metal nanoclusters have served as an emerging class of modular nanomaterials. Several efficient strategies have been proposed for transforming cluster precursors into new nanoclusters with customized structures and enhanced performance. However, such nanocluster transformations have still been in a "blind box" state, meaning that the existing intermediates were hard to track with atomic precision. Herein, we present a "slice visualization" approach for in-depth imaging of the nanocluster transformation from Au1Ag24(SR)18 to Au1Ag30(SR)20. With this approach, two cluster intermediates, namely, Au1Ag26(SR)19 and Au1Ag28(SR)20, were monitored with atomic precision. The four nanoclusters constituted a correlated Au1Ag24+2n (n = 0, 1, 2, and 3) cluster series with comparable structural features─the same Au1Ag12 icosahedral kernel but evolutionary peripheral motif structures. The mechanism of nanocluster structure growth was mapped in detail─insertion of Ag2(SR)1 or Ag-induced assembly of surface subunits. The presented "slice visualization" approach not only contributes an ideal cluster platform for in-depth investigations of structure-property correlations but also hopefully acts as a powerful means for obtaining clear information on nanocluster structure evolution.

16.
Clin Neurol Neurosurg ; 228: 107710, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-37043845

RESUMEN

BACKGROUND: Idiopathic trigeminal neuralgia (ITN) is one of the most common types of neuropathic pain, severely affecting the physiological and psychological wellbeing of patients. Recently, fMRI has been used to examine abnormal activation of brain regions in patients with ITN. However, sample sizes have been small in these few studies, and the abnormally activated brain regions remain unclear. Therefore, in the present study, we retrieved and analyzed literature on the brain areas with abnormal or reduced activation in ITN patients, with the aim of providing insight into the neuropathological basis of the disease and to provide new targets for treatment. METHODS: We retrieved resting state fMRI studies on trigeminal neuralgia patients from PubMed, the Web of Science and Scopus databases until November 2022, and we extracted the coordinates of the sites with increased or decreased activation. We used activation likelihood estimation (ALE) meta-analysis to identify regions of abnormal activation in ITN patients. RESULTS: ALE meta-analysis revealed that the left caudate nucleus and right anterior ventral nucleus of the thalamus are abnormally hyperactivated in ITN patients. Moreover, ITN patients showed reduced activation in the left precuneus, middle temporal gyrus, lingual gyrus, and medial frontal gyrus. CONCLUSION: ALE meta-analysis identified several brain regions with abnormally high or decreased activation in ITN patients. Sites with altered activation may be potential targets for non-invasive brain stimulation as adjunct therapy for ITN.


Asunto(s)
Neuralgia , Neuralgia del Trigémino , Humanos , Neuralgia del Trigémino/diagnóstico por imagen , Imagen por Resonancia Magnética , Funciones de Verosimilitud , Encéfalo/diagnóstico por imagen
17.
RSC Chem Biol ; 4(2): 138-145, 2023 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-36794022

RESUMEN

We have developed a non-cationic transfection vector in the form of bottlebrush polymer-antisense oligonucleotide (ASO) conjugates. Termed pacDNA (polymer-assisted compaction of DNA), these agents show improved biopharmaceutical characteristics and antisense potency in vivo while suppressing non-antisense side effects. Nonetheless, there still is a lack of the mechanistic understanding of the cellular uptake, subcellular trafficking, and gene knockdown with pacDNA. Here, we show that the pacDNA enters human non-small cell lung cancer cells (NCI-H358) predominantly by scavenger receptor-mediated endocytosis and macropinocytosis and trafficks via the endolysosomal pathway within the cell. The pacDNA significantly reduces a target gene expression (KRAS) in the protein level but not in the mRNA level, despite that the transfection of certain free ASOs causes ribonuclease H1 (RNase H)-dependent degradation of KRAS mRNA. In addition, the antisense activity of pacDNA is independent of ASO chemical modification, suggesting that the pacDNA always functions as a steric blocker.

18.
Nanoscale ; 15(7): 3560-3565, 2023 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-36723135

RESUMEN

Transition-metal clusters have attracted great attention in catalysis due to their unique reactivity and electronic properties, especially for novel substrate binding and activation modes at the bridging coordination sites of metal clusters. Although palladium complexes have demonstrated outstanding catalytic performance in various transformations, the catalytic behaviors of polynuclear palladium clusters in many important synthetic methodologies remain much less explored so far. Herein, we disclose the use of an atomically defined tri-nuclear palladium (Pd3Cl) species as a catalyst precursor in Ag(I)-assisted direct C-H arylation with aryl iodides under mild conditions. This catalyst system leads to the formation of synthetically important biaryls in good yields with high site selectivities without the assistance of directing groups.

19.
Chem Sci ; 13(48): 14357-14365, 2022 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-36545150

RESUMEN

Exploring the structural evolution of clusters with similar sizes and atom numbers induced by the removal or addition of a few atoms contributes to a deep understanding of structure-property relationships. Herein, three well-characterized copper-hydride nanoclusters that provide insight into the surface-vacancy-defect to non-defect structural evolution were reported. A surface-defective copper hydride nanocluster [Cu28(S-c-C6H11)18(PPh2Py)3H8]2+ (Cu28-PPh2Py for short) with only one C 1 symmetry axis was synthesized using a one-pot method under mild conditions, and its structure was determined. Through ligand regulation, a 29th copper atom was inserted into the surface vacancy site to give two non-defective copper hydride nanoclusters, namely [Cu29(SAdm)15Cl3(P(Ph-Cl)3)4H10]+ (Cu29-P(Ph-Cl)3 for short) with one C 3 symmetry axis and (Cu29(S-c-C6H11)18(P(Ph-pMe)3)4H10)+ (Cu29-P(Ph-Me)3 for short) with four C 3 symmetry axes. The optimized structures show that the 10 hydrides cap four triangular and all six square-planar structures of the cuboctahedral Cu13 core of Cu29-P(Ph-Me)3, while the 10 hydrides cap four triangular and six square-planar structures of the anti-cuboctahedral Cu13 core of Cu29-P(Ph-Cl)3, with the eight hydrides in Cu28-PPh2Py capping four triangular and four square planar-structures of its anti-cuboctahedral Cu13 core. Cluster stability was found to increase sequentially from Cu28-PPh2Py to Cu29-P(Ph-Cl)3 and then to Cu29-P(Ph-Me)3, which indicates that stability is affected by the overall structure of the cluster. Structural adjustments to the metal core, shell, and core-shell bonding model, in moving from Cu28-PPh2Py to Cu29-P(Ph-Cl)3 and then to Cu29-P(Ph-Me)3, enable the structural evolution and mechanism responsible for their physicochemical properties to be understood and provide valuable insight into the structures of surface vacancies in copper nanoclusters and structure-property relationships.

20.
J Am Chem Soc ; 144(50): 23205-23213, 2022 Dec 21.
Artículo en Inglés | MEDLINE | ID: mdl-36484475

RESUMEN

The construction of helical nanosized superstructures has long been a challenging pursuit, and little has been achieved in terms of atomic-level manipulation. Herein, intercluster hierarchical triple-helical structures were presented from all-thiol-stabilized Au6Cu6(4-MeOBT)12 nanoclusters by investigating their structures from both molecular and supramolecular aspects. Based on the atomically precise structure, the mechanism of intercluster assembly was elucidated, and the results indicated an intracluster rotation-induced self-assembly process. Specifically, the presence of abundant intermolecular interactions, including π-π stacking, C-H···O hydrogen bonding, and C-H···π interactions, was found to be beneficial for the organization of the triple-helical superstructure of metal clusters. Moreover, DFT calculations and UV-vis, Raman, and transient absorption measurements were performed to observe the different electronic structures between the nanocluster monomers and helical aggregates. Overall, this work presents an exciting example of the hierarchical triple-helical assembly of atomically precise nanoclusters, which allows an in-depth understanding of complex helical structures/behaviors at the atomic level.

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