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1.
J Pers Med ; 14(6)2024 May 28.
Article in English | MEDLINE | ID: mdl-38929799

ABSTRACT

Age-related sleep disorders share common pathways with sarcopenia. Prospective data from Latin American populations are scarce, and the association between sleep disorders and sarcopenia in Chileans remains unknown. Thus, we aimed to study the longitudinal association between sleep disorders and sarcopenia in a cohort study of 1116 community-dwelling Chilean older people ≥60 years old from the ALEXANDROS cohorts. After the exclusion criteria, 318 subjects were followed. Sociodemographic data, self-reported chronic diseases, sedentarism, sleep characteristics, anthropometric measurements, handgrip strength, and muscle performance were assessed. Results indicated that at baseline, the prevalence of sarcopenia was 24.10% without gender differences, and the prevalence of self-reported sleep problems was 23.3%, higher in women (26.46% versus 17.15% in men). The adjusted Cox regression models for sarcopenia showed an association between sarcopenia, sleep disorders (HR = 2.08, 95% IC 1.14-3.80), and long sleep duration (HR = 2.42, 95% IC 1.20-4.91). After 8.24 years of follow-up, there were 2.2 cases of sarcopenia per 100 person-years. This study demonstrates that sleep disorders are an independent risk factor for sarcopenia in Chilean older people. The identification of sleep disorders through self-reported data provides an opportunity for early identification of risk and cost-effective sarcopenia prevention.

3.
Front Cell Dev Biol ; 12: 1301433, 2024.
Article in English | MEDLINE | ID: mdl-38778912

ABSTRACT

Aging population has led to an increased prevalence of chronic and degenerative pathologies. A manifestation of unhealthy aging is frailty, a geriatric syndrome that implies a non-specific state of greater vulnerability. Currently, methods for frailty diagnosis are based exclusively on clinical observation. The aim of this study is to determine whether the bioenergetic capacity defined as mitochondrial oxygen consumption rate (OCR) of peripheral circulation mononuclear cells (PBMC) associates with the frailty phenotype in older adults and with their nutritional status. This is a cross-sectional analytic study of 58 participants 70 years and older, 18 frail and 40 non-frail adults, from the ALEXANDROS cohort study, previously described. Participants were characterized through sociodemographic and anthropometric assessments. Frail individuals displayed a higher frequency of osteoporosis and depression. The mean age of the participants was 80.2 ± 5.2 years, similar in both groups of men and women. Regarding the nutritional status defined as the body mass index, most non-frail individuals were normal or overweight, while frail participants were mostly overweight or obese. We observed that OCR was significantly decreased in frail men (p < 0.01). Age was also associated with significant differences in oxygen consumption in frail patients, with lower oxygen consumption being observed in those over 80 years of age. Therefore, the use of PBMC can result in an accessible fingerprint that may identify initial stages of frailty in a minimally invasive way.

4.
Biosens Bioelectron ; 250: 116040, 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38290380

ABSTRACT

The COVID-19 pandemic has taught us valuable lessons, especially the urgent need for a widespread, rapid and sensitive diagnostic tool. To this, the integration of bidimensional nanomaterials, particularly graphene, into point-of-care biomedical devices is a groundbreaking strategy able to potentially revolutionize the diagnostic landscape. Despite advancements in the fabrication of these biosensors, the relationship between their surface biofunctionalization and sensing performance remains unclear. Here, we demonstrate that the combination of careful sensor fabrication and its precise surface biofunctionalization is crucial for exalting the sensing performances of 2D biosensors. Specifically, we have biofunctionalized Graphene Field-Effect Transistor (GFET) sensors surface through different biochemical reactions to promote either random/heterogeneous or oriented/homogeneous immobilization of the Anti-SARS-CoV-2 spike protein antibody. Each strategy was thoroughly characterized by in-silico simulations, physicochemical and biochemical techniques and electrical characterization. Subsequently, both biosensors were tested in the label-free direct titration of SARS-CoV-2 virus in simulated clinical samples, avoiding sample preprocessing and within short timeframes. Remarkably, the oriented GFET biosensor exhibited significantly enhanced reproducibility and responsiveness, surpassing the detection sensitivity of conventional non-oriented GFET by more than twofold. This breakthrough not only involves direct implications for COVID-19 surveillance and next pandemic preparedness but also clarify an unexplored mechanistic dimension of biosensor research utilizing 2D-nanomaterials.


Subject(s)
Biosensing Techniques , COVID-19 , Graphite , Humans , SARS-CoV-2 , COVID-19/diagnosis , Biosensing Techniques/methods , Graphite/chemistry , Pandemics , Reproducibility of Results
5.
Foods ; 12(20)2023 Oct 19.
Article in English | MEDLINE | ID: mdl-37893719

ABSTRACT

There is a severe need to develop a sustainable, affordable, and nutritious food supply system. Broccoli microgreens have attracted attention due to their rich nutritional content and abundant bioactive compounds, constituting an important opportunity to feed the ever-increasing population and fight global health problems. This study aimed to measure the impact of the combined application of biofertilizers and zinc and iron nanofertilizers on plant growth and the biofortification of glucosinolates (GLSs) and micronutrients in broccoli microgreens. Biofertilizers were based on plant growth-promoting (PGP) bacterial consortia previously isolated and characterized for multiple PGP traits. Nanofertilizers consisted of ZnO (77 nm) and γ-Fe2O3 (68 nm) nanoparticles synthesized with the coprecipitation method and functionalized with a Pseudomonas species preparation. Treatments were evaluated under seedbed conditions. Plant growth parameters of plant height (37.0-59.8%), leaf diameter (57.6-81.1%) and fresh weight (112.1-178.0%), as well as zinc (122.19-363.41%) and iron contents (55.19-161.57%), were mainly increased by nanoparticles subjected to the functionalization process with Pseudomonas species and uncapped NPs applied together with the biofertilizer treatment. Regarding GLSs, eight compounds were detected as being most positively influenced by these treatments. This work demonstrated the synergistic interactions of applying ZnO and γ-Fe2O3 nanofertilizers combined with biofertilizers to enhance plant growth and biofortify micronutrients and glucosinolates in broccoli microgreens.

6.
Plants (Basel) ; 12(20)2023 Oct 23.
Article in English | MEDLINE | ID: mdl-37896120

ABSTRACT

Micronutrient deficiencies are widespread and growing global concerns. Nanoscale nutrients present higher absorption rates and improved nutrient availability and nutrient use efficiency. Co-application of nanofertilizers (NFs) with biological agents or organic compounds increases NF biocompatibility, stability, and efficacy. This study aimed to develop and evaluate zinc and iron bio-nanofertilizers formulated with plant growth-promoting rhizobacteria (PGPR) and microalgae. Nanoparticles (NPs) were synthesized with the co-precipitation method and functionalized with Pseudomonas species and Spirulina platensis preparation. NPs were characterized and evaluated on seed germination, soil microbial growth, and early plant response under seedbed conditions. NPs corresponded to zinc oxide (ZnO; 77 nm) and maghemite (γ-Fe2O3; 68 nm). Functionalized nanoparticles showed larger sizes, around 145-233 nm. The seedling vigor index of tomato and maize was significantly increased (32.9-46.1%) by bacteria-functionalized ZnO- and γ-Fe2O3-NPs at 75 ppm. NFs at 250 and 75 ppm significantly increased bacterial growth. NFs also improved early plant growth by increasing plant height (14-44%), leaf diameter (22-47%), and fresh weight (46-119%) in broccoli and radish, which were mainly influenced by bacteria capped ZnO- and γ-Fe2O3-NPs at 250 ppm. Beneficial effects on plant growth can be attributed to the synergistic interaction of the biological components and the zinc and iron NPs in the bio-nanofertilizers.

7.
Plants (Basel) ; 12(18)2023 Sep 13.
Article in English | MEDLINE | ID: mdl-37765426

ABSTRACT

Plant growth-promoting microorganisms (PGPM) benefit plant health by enhancing plant nutrient-use efficiency and protecting plants against biotic and abiotic stresses. This study aimed to isolate and characterize autochthonous PGPM from important agri-food crops and nonagricultural plants to formulate biofertilizers. Native microorganisms were isolated and evaluated for PGP traits (K, P, and Zn solubilization, N2-fixation, NH3-, IAA and siderophore production, and antifungal activity against Fusarium oxysporum). Isolates were tested on radish and broccoli seedlings, evaluating 19 individual isolates and 12 microbial consortia. Potential bacteria were identified through DNA sequencing. In total, 798 bacteria and 209 fungi were isolated. Isolates showed higher mineral solubilization activity than other mechanisms; 399 bacteria and 156 fungi presented mineral solubilization. Bacteria were relevant for nitrogen fixation, siderophore, IAA (29-176 mg/L), and ammonia production, while fungi for Fusarium growth inhibition (40-69%). Twenty-four bacteria and eighteen fungi were selected for their PGP traits. Bacteria had significantly (ANOVA, p < 0.05) better effects on plants than fungi; treatments improved plant height (23.06-51.32%), leaf diameter (25.43-82.91%), and fresh weight (54.18-85.45%) in both crops. Most potential species belonged to Pseudomonas, Pantoea, Serratia, and Rahnella genera. This work validated a high-throughput approach to screening hundreds of rhizospheric microorganisms with PGP potential isolated from rhizospheric samples.

8.
Commun Chem ; 6(1): 141, 2023 Jul 05.
Article in English | MEDLINE | ID: mdl-37407755

ABSTRACT

Phosphoramidates are common and widespread backbones of a great variety of fine chemicals, pharmaceuticals, additives and natural products. Conventional approaches to their synthesis make use of toxic chlorinated reagents and intermediates, which are sought to be avoided at an industrial scale. Here we report the coupling of phosphites and amines promoted by a Cu3[Co(CN)6]2-based double metal cyanide heterogeneous catalyst using I2 as additive for the synthesis of phosphoramidates. This strategy successfully provides an efficient, environmentally friendly alternative to the synthesis of these valuable compounds in high yields and it is, to the best of our knowledge, the first heterogeneous approach to this protocol. While the detailed study of the catalyst structure and of the metal centers by PXRD, FTIR, EXAFS and XANES revealed changes in their coordination environment, the catalyst maintained its high activity for at least 5 consecutive iterations of the reaction. Preliminary mechanism studies suggest that the reaction proceeds by a continuous change in the oxidation state of the Cu metal, induced by a O2/I- redox cycle.

9.
Int J Mol Sci ; 24(9)2023 Apr 29.
Article in English | MEDLINE | ID: mdl-37175789

ABSTRACT

The glucose uptake in skeletal muscle is essential to produce energy through ATP, which is needed by this organ to maintain vital functions. The impairment of glucose uptake compromises the metabolism and function of skeletal muscle and other organs and is a feature of diabetes, obesity, and ageing. There is a need for research to uncover the mechanisms involved in the impairment of glucose uptake in skeletal muscle. In this study, we adapted, developed, optimised, and validated a methodology based on the fluorescence glucose analogue 6-NBDG, combined with a quantitative fluorescence microscopy image analysis, to determine the glucose uptake in two models of skeletal muscle cells: C2C12 myotubes and single fibres isolated from muscle. It was proposed that reactive oxygen and nitrogen species (RONS) and redox homeostasis play an important role in the modulation of intracellular redox signalling pathways associated with glucose uptake. In this study, we prove that the prooxidative intracellular redox environment under oxidative eustress produced by RONS such as hydrogen peroxide and nitric oxide improves glucose uptake in skeletal muscle cells. However, when oxidation is excessive, oxidative distress occurs, and cellular viability is compromised, although there might be an increase in the glucose uptake. Based on the results of this study, the determination of 6-NBDG/glucose uptake in myotubes and skeletal muscle cells is feasible, validated, and will contribute to improve future research.


Subject(s)
Muscle Fibers, Skeletal , Muscle, Skeletal , Muscle Fibers, Skeletal/metabolism , Muscle, Skeletal/metabolism , Oxidation-Reduction , Homeostasis , Reactive Oxygen Species/metabolism , Glucose/metabolism
10.
Alzheimers Dement ; 19(9): 4046-4060, 2023 09.
Article in English | MEDLINE | ID: mdl-37204054

ABSTRACT

INTRODUCTION: Latin American Initiative for Lifestyle Intervention to Prevent Cognitive Decline (LatAm-FINGERS) is the first non-pharmacological multicenter randomized clinical trial (RCT) to prevent cognitive impairment in Latin America (LA). Our aim is to present the study design and discuss the strategies used for multicultural harmonization. METHODS: This 1-year RCT (working on a 1-year extension) investigates the feasibility of a multi-domain lifestyle intervention in LA and the efficacy of the intervention, primarily on cognitive function. An external harmonization process was carried out to follow the FINGER model, and an internal harmonization was performed to ensure this study was feasible and comparable across the 12 participating LA countries. RESULTS: Currently, 1549 participants have been screened, and 815 randomized. Participants are ethnically diverse (56% are Nestizo) and have high cardiovascular risk (39% have metabolic syndrome). DISCUSSION: LatAm-FINGERS overcame a significant challenge to combine the region's diversity into a multi-domain risk reduction intervention feasible across LA while preserving the original FINGER design.


Subject(s)
Cognitive Dysfunction , Humans , Latin America , Cognitive Dysfunction/prevention & control , Life Style , Cognition , Research Design
11.
J Microbiol Methods ; 208: 106711, 2023 05.
Article in English | MEDLINE | ID: mdl-37015312

ABSTRACT

Entomopathogenic fungi (EPF) preservation aims to maintain valuable characteristics. Growth, conidiation and genetic stability of eight species of EPF were evaluated in six preservation methods for up to 8.2 years. Cryopreservation at -196 °C, freeze-drying, and ultra-freezing at -70 °C resulted as the best methods for long-term storage.


Subject(s)
Cryopreservation , Cryopreservation/methods , Freeze Drying/methods , Freezing
12.
Mater Horiz ; 10(5): 1625-1640, 2023 May 09.
Article in English | MEDLINE | ID: mdl-36861895

ABSTRACT

Polystyrene (PS) is one of the most popular plastics due to its versatility, which renders it useful for a large variety of applications, including laboratory equipment, insulation and food packaging. However, its recycling is still a challenge, as both mechanical and chemical (thermal) recycling strategies are often cost-prohibitive in comparison to current disposal methods. Therefore, catalytic depolymerization of PS represents the best alternative to overcome these economical drawbacks, since the presence of a catalyst can improve product selectivity for chemical recycling and upcycling of PS. This minireview focuses on the catalytic processes for the production of styrene and other valuable aromatics from PS waste, and it aims to lay the ground for PS recyclability and long-term sustainable PS production.

13.
PeerJ ; 11: e15047, 2023.
Article in English | MEDLINE | ID: mdl-36974135

ABSTRACT

Background: Begomoviruses are circular single-stranded DNA plant viruses that cause economic losses worldwide. Weeds have been pointed out as reservoirs for many begomoviruses species, especially from members of the Sida and Malvastrum genera. These weeds have the ability to host multiple begomoviruses species simultaneously, which can lead to the emergence of new viral species that can spread to commercial crops. Additionally, begomoviruses have a natural tendency to recombine, resulting in the emergence of new variants and species. Methods: To explore the begomoviruses biodiversity in weeds from genera Sida and Malvastrum in Colima, México, we collected symptomatic plants from these genera throughout the state. To identify BGVs infecting weeds, we performed circular DNA genomics (circomics) using the Illumina platform. Contig annotation was conducted with the BLASTn tool using the GenBank nucleotide "nr" database. We corroborated by PCR the presence of begomoviruses in weeds samples and isolated and sequenced the complete genome of a probable new species of begomovirus using the Sanger method. The demarcation process for new species determination followed the International Committee on Taxonomy of Viruses criteria. Phylogenetic and recombination analyses were implemented to infer the evolutionary relationship of the new virus. Results: We identified a new begomovirus species from sida and malvastrum plants that has the ability to infect Cucumis sativus L. According to our findings, the novel species Sida chlorotic leaf virus is the result of a recombination event between one member of the group known as the Squash leaf curl virus (SLCV) clade and another from the Abutilon mosaic virus (AbMV) clade. Additionally, we isolated three previously identified begomoviruses species, two of which infected commercial crops: okra (Okra yellow mosaic Mexico virus) and cucumber (Cucumber chlorotic leaf virus). Conclusion: These findings support the idea that weeds act as begomovirus reservoirs and play essential roles in begomovirus biodiversity. Therefore, controlling their populations near commercial crops must be considered in order to avoid the harmful effects of these phytopathogens and thus increase agricultural efficiency, ensuring food and nutritional security.


Subject(s)
Begomovirus , Cucumis sativus , Malvaceae , Sida Plant , Begomovirus/genetics , Cucumis sativus/genetics , Phylogeny , DNA, Viral/genetics , Base Sequence , Malvaceae/genetics
14.
Article in English | MEDLINE | ID: mdl-36767070

ABSTRACT

INTRODUCTION: The SARS-CoV-2 pandemic generated the need to keep immunosuppressed patients away from hospital institutions for as long as possible. This in turn stimulated the implementation of a home hospitalization model for autologous hematopoietic stem-cell transplantation (HSCT). PURPOSE: To analyze whether there are significant differences in post-transplantation complications related to catheters observed in patients treated in the home-transplant care modality compared to patients treated in the hospital. METHODOLOGY: Observational, analytical, longitudinal, and retrospective study of cases and controls. A convenience sample was chosen, in which the cases comprised 20 patients included in the home HSCT care model. For each patient, it was considered suitable to propose two controls among those who received autologous transplantation in the last five years with a baseline demographic and pathological profile similar to the case for whom they were control. RESULTS: The home patients achieved an average of 22.4 ± 2.6 days of evolution with an average of 16.4 ± 2.08 days post-transplant, compared to the hospital process with an average of 21.21 ± 4.18 days of evolution and 15.51 ± 3.96 days post-transplant (evolution days p = 0.022; post-transplant days p = 0.002). A higher percentage of use of parenteral nutrition (p = 0.036) and transfusions (p = 0.003) was observed during the post-transplant phase in the hospital. The rest of the therapeutic measures did not show significant differences. When analyzing the frequency of adverse effects in the post-transplant phase, a significant increase in neutropenic fever (OR = 8.55) and positive blood cultures (OR = 6.65) was observed in hospital patients. Any other significant differences in other variables related to PICC were found (presence and days of neutropenic fever, catheter infection, complications, pathogens, admission to the ICU, or death). Concerning local complications (pain, DVT, Medical adhesive-related Skin Injury, and erythema), there was more erythema in the hospital (p = 0.056). CONCLUSIONS: The results obtained indicate that regarding the appearance of complications associated with PICCs in home hospitalization HSCT patients, there are no significant differences compared to hospitalization, so that home care can be a safe context for people with these lines.


Subject(s)
COVID-19 , Catheterization, Central Venous , Hematopoietic Stem Cell Transplantation , Humans , Catheterization, Central Venous/methods , Catheters , COVID-19/etiology , Hematopoietic Stem Cell Transplantation/adverse effects , Hospitalization , Retrospective Studies , Risk Factors , SARS-CoV-2 , Transplantation, Autologous/adverse effects
15.
Chem Commun (Camb) ; 59(16): 2319-2322, 2023 Feb 21.
Article in English | MEDLINE | ID: mdl-36748559

ABSTRACT

The oxidative carbonylation of N-protected indoles was investigated to directly synthesize indole-3-carboxylic acids. Using Rh(III)-zeolites as heterogeneous catalysts, the single-site Rh-species reach unprecedented activities (>100 turnovers), while the metal is readily recovered after reaction. X-ray absorption spectroscopy (XAS) provided evidence for site-isolation of Rh(III) species on the zeolite.

16.
Haemophilia ; 29(1): 45-50, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36222220

ABSTRACT

The World Federation of Haemophilia (WFH) is a global network of national member organizations (NMOs) that advocate, collectively and individually, to improve lives of people with inherited bleeding disorders. The WFH vision of "Treatment for All" speaks to a future in which all people with an inherited bleeding disorder will have access to care, regardless of their gender or where they live. Over the last several years, initiatives including the WFH Humanitarian Aid program, the World Bleeding Disorders Registry, and Guidelines for the Management of Haemophilia and von Willebrand disease have significantly changed how the WFH and its partners work to improve and sustain care for people with bleeding disorders. Following an extensive consultation that included over 200 stakeholders from 70 countries, a Theory of Change was developed, and strategic priorities identified, to clearly define the WFH's intended impact and point of accountability to its stakeholders, and to determine how and through who those goals will be achieved. Both should help the WFH better support its NMOs and healthcare providers around the world in their efforts to improve access to diagnosis and care, as new therapies revolutionize the treatment landscape and the fallout of the global pandemic continues to challenge the ways in which we work and connect. Global collaboration of all stakeholders, based on their resources, objectives and skills, will be required to achieve these goals and to ensure more people have reliable access to safe treatment and care, regardless of their bleeding disorder, gender, or where they live.


Subject(s)
Hemophilia A , von Willebrand Diseases , Humans , Hemophilia A/therapy , Health Personnel
17.
Medicina (Kaunas) ; 60(1)2023 Dec 26.
Article in English | MEDLINE | ID: mdl-38256305

ABSTRACT

Background and Objectives: The increase in indications for hematopoietic cell transplants (HCTs) has led to the development of new care options after said transplant, such as home care after transplantation, which improves the patients' quality of life. The main purpose of this research is to analyze the differences in the appearance of post-transplant complications between patients having underwent autologous HCT with at-home post-transplant modalities and those under in-hospital post-transplant care. Materials and Methods: An observational, analytical, longitudinal, and retrospective study of cases and controls. All transplanted people in the domiciliary model since 2020 are included as cases (20 subjects). For each case, two controls (40 subjects) are proposed among patients who received an autologous transplant in a hospital in the last five years with a similar demographic and pathological base profile in each case. Results: No significant differences were found between cases and controls, except for the Karnofsky value, which was higher in people receiving home treatment (91.7% vs. 87.74%; p = 0.05). The average number of days of the process post-transplantation was more significant at home (processing days 22.4 ± 2.6; post-transplantation days of 16.4 ± 2.08 versus 21.21 ± 4.18, with a mean of 15.51 ± 3.96 days post-transplant (days of the process p = 0.022; days post-transplant p = 0.002)). There is a more significant presence of neutropenic fever, mucositis, and positive blood cultures in the post-transplant patients who remain in the hospital. In contrast, the patients receiving home care post-transplantation undergo significantly more weight loss. Regarding the odds ratio of the appearance of adverse events, in the hospital setting, it is up to 8.5 times more likely to encounter neutropenic fever, 4.63 times more likely for mucositis, and 6.65 times more likely for the presence of pathogens in blood cultures. Conclusions: The home care modality in the post-transplant phase does not show an inferiority in conditions in the management and safety of the patient concerning the appearance of adverse events. However, more significant weight loss is detected in patients at home, and an increased risk of episodes of neutropenic fever, mucositis, and positive blood cultures for patients in hospital settings.


Subject(s)
Hematopoietic Stem Cell Transplantation , Home Care Services , Mucositis , Humans , Quality of Life , Retrospective Studies , Hematopoietic Stem Cell Transplantation/adverse effects , Weight Loss
18.
Plants (Basel) ; 11(24)2022 Dec 12.
Article in English | MEDLINE | ID: mdl-36559589

ABSTRACT

Obesity is a critical medical condition worldwide that is increasingly involved with nutritional derangements associated with micronutrient deficiencies, including iron, zinc, calcium, magnesium, selenium, and vitamins A, C, D, and E. Nutritional deficiencies in obesity are mainly caused by poor-quality diets, higher nutrient requirements, alterations in micronutrient metabolism, and invasive obesity treatments. The current conventional agricultural system is designed for intensive food production, focusing on food quantity rather than food quality, consuming excessive agricultural inputs, and producing nutrient-deficient foods, thus generating severe health and environmental problems; agricultural food products may worsen obesity-related malnutrition. Therefore, modern agriculture is adopting new biofortification technologies to combat micronutrient deficiencies and improve agricultural productivity and sustainability. Biofertilization and nanofertilization practices are increasingly used due to their efficiency, safety, and reduced environmental impact. Biofertilizers are preparations of PGP-microorganisms that promote plant growth by influencing plant metabolism and improving the nutrient uptake, and nanofertilizers consist of synthesized nanoparticles with unique physicochemical properties that are capable of increasing plant nutrition and enriching agricultural products. This review presents the current micronutrient deficiencies associated with obesity, the modern unsustainable agri-food system contributing to obesity progression, and the development of bio- and nanofertilizers capable of biofortifying agri-food crops with micronutrients commonly deficient in patients with obesity.

19.
ACS Appl Mater Interfaces ; 14(46): 51867-51880, 2022 Nov 23.
Article in English | MEDLINE | ID: mdl-36349551

ABSTRACT

Electrophilic amination has emerged as a more environmentally benign approach to construct arene C-N bonds. However, heterogeneous catalysts remain largely unexplored in this area, even though their use could facilitate product purification and catalyst recovery. Here we investigate strategies to heterogenize a Cu(2,2'-bipyridine) catalyst for the amination of arenes lacking a directing group with hydroxylamine-O-sulfonic acid (HOSA). Besides immobilization of Cu on a metal-organic framework (MOF) or covalent organic framework (COF) with embedded 2,2'-bipyridines, a ship-in-a-bottle approach was followed in which the Cu complex is encapsulated in the pores of a zeolite. Recyclability and hot centrifugation tests show that zeolite Beta-entrapped CuII(2,2'-bipyridine) is superior in terms of stability. With N-methylmorpholine as a weakly coordinating, weak base, simple arenes, such as mesitylene, could be aminated with yields up to 59%, corresponding to a catalyst TON of 24. The zeolite could be used in three consecutive runs without a decrease in activity. Characterization of the catalyst by EPR and XAS showed that the active catalytic complex consisted of a site-isolated CuII species with one 2,2'-bipyridine ligand.

20.
Chem Sci ; 13(31): 9035-9046, 2022 Aug 10.
Article in English | MEDLINE | ID: mdl-36091218

ABSTRACT

Adsorptive separation is a promising lower-energy alternative for traditional industrial separation processes. While carbon-based materials have a long history in adsorptive removal of organic contaminants from solution or gas mixtures, separation using an adsorption/desorption protocol is rarely considered. The main drawbacks are the limited control in bulk adsorption experiments, as often all organic molecules are adsorbed, and lack of desorption methods to retrieve the adsorbed molecules. Using high-resolution on-surface characterization with scanning tunneling microscopy (STM), an increased understanding of the on-surface adsorption behavior under different conditions was obtained. The insight obtained from the nanoscale experiments was used to develop a highly selective separation method using adsorption and desorption on graphite, which was tested for the separation of quinonoid zwitterions. These experiments on adsorptive separation using self-assembly on graphite show its potential and demonstrate the advantage of combining surface characterization techniques with bulk experiments to exploit different possible applications of carbon-based materials.

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