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Chemical Science May 2024Bismuth, in spite of its low cost and low toxicity, has found limited application in organic synthesis. Although the photoactivity of Bi(iii) salts has been well...
Bismuth, in spite of its low cost and low toxicity, has found limited application in organic synthesis. Although the photoactivity of Bi(iii) salts has been well studied, this has not been effectively exploited in photocatalysis. To date, only a single report exists for the Bi-based photocatalysis, wherein carbon centered radicals were generated using ligand to metal charge transfer (LMCT) on bismuth. In this regard, expanding the horizon of bismuth LMCT catalysis for the generation of heteroatom centered radicals, we hereby report an efficient radical phosphonylation using BiCl as the LMCT catalyst. Phosphonyl radicals generated visible-light induced LMCT of BiCl were subjected to a variety of transformations like alkylation, amination, alkynylation and cascade cyclizations. The catalytic system tolerated a wide range of substrate classes, delivering excellent yields of the scaffolds. The reactions were scalable and required low catalytic loading of bismuth. Detailed mechanistic studies were carried out to probe the reaction mechanism. Diverse radical phosphonylations leading to the formation of sp-C-P, sp-C-P, sp-C-P, and P-N bonds in the current work present the candidacy of bismuth as a versatile photocatalyst for small molecule activation.
PubMed: 38756813
DOI: 10.1039/d4sc00692e -
International Journal of Molecular... May 2024This current study assessed the impacts of morphology adjustment of perovskite BiFeO (BFO) on the construction and photocatalytic activity of P-infused g-CN/U-BiFeO...
This current study assessed the impacts of morphology adjustment of perovskite BiFeO (BFO) on the construction and photocatalytic activity of P-infused g-CN/U-BiFeO (U-BFO/PCN) heterostructured composite photocatalysts. Favorable formation of U-BFO/PCN composites was attained via urea-aided morphology-controlled hydrothermal synthesis of BFO followed by solvosonication-mediated fusion with already synthesized P-g-CN to form U-BFO/PCN composites. The prepared bare and composite photocatalysts' morphological, textural, structural, optical, and photocatalytic performance were meticulously examined through various analytical characterization techniques and photodegradation of aqueous rhodamine B (RhB). Ellipsoids and flakes morphological structures were obtained for U-BFO and BFO, and their effects on the successful fabrication of the heterojunctions were also established. The U-BFO/PCN composite exhibits 99.2% efficiency within 20 min of visible-light irradiation, surpassing BFO/PCN (88.5%), PCN (66.8%), and U-BFO (26.1%). The pseudo-first-order kinetics of U-BFO/PCN composites is 2.41 × 10 min, equivalent to 2.2 times, 57 times, and 4.3 times of BFO/PCN (1.08 × 10 min), U-BFO, (4.20 × 10 min), and PCN, (5.60 × 10 min), respectively. The recyclability test demonstrates an outstanding photostability for U-BFO/PCN after four cyclic runs. This improved photocatalytic activity exhibited by the composites can be attributed to enhanced visible-light utilization and additional accessible active sites due to surface and electronic band modification of CN via P-doping and effective charge separation achieved via successful composites formation.
Topics: Catalysis; Bismuth; Photolysis; Rhodamines; Light; Ferric Compounds; Nitrogen Compounds; Titanium; Photochemical Processes; Nitriles; Kinetics; Graphite; Oxides; Calcium Compounds
PubMed: 38732166
DOI: 10.3390/ijms25094948 -
Molecules (Basel, Switzerland) May 2024Activated carbon/BiOI nanocomposites were successfully synthesized through a simplistic method. The produced composites were then characterized using XRD, TEM, SEM-EDX,...
Activated carbon/BiOI nanocomposites were successfully synthesized through a simplistic method. The produced composites were then characterized using XRD, TEM, SEM-EDX, and XPS. The results showed that BiOI with a tetragonal crystal structure had been formed. The interaction between activated carbon and BiOI was confirmed via all the mentioned tools. The obtained nanocomposites' electrical conductivity, dielectric properties, and Ac impedance were studied at 59 KHz-1.29 MHz. AC and dc conductivities were studied at temperatures between 303 and 573 K within the frequency range of 59 KHz-1.29 MHz. The 10% activated carbon/BiOI nanocomposite possessed dc and AC conductivity values of 5.56 × 10 and 2.86 × 10 Ω.cm, respectively, which were higher than BiOI and the other nanocomposites. Every sample exhibited increased electrical conductivity values as the temperature and frequency rose, suggesting that all samples had semiconducting behavior. The loss and dielectric constants (ε' and ε″) also dropped as the frequency increased, leading to higher dielectric loss. The Nyquist plot unraveled single semicircle arcs and a decreased bulk resistance, indicating decreased grain boundary resistance. Consequently, the electrical characteristics of BiOI, 1C/BiOI, 5C/BiOI, and 10C/BiOI implied their applicability as dielectric absorbers, charge-stored capacitors, and high-frequency microwave devices.
PubMed: 38731573
DOI: 10.3390/molecules29092082 -
Materials (Basel, Switzerland) Apr 2024Bismuth ferrite BiFeO (BFO)-based ferroelectrics have great potential as inorganic perovskite-like oxides for future solar cells applications due to their unique...
Bismuth ferrite BiFeO (BFO)-based ferroelectrics have great potential as inorganic perovskite-like oxides for future solar cells applications due to their unique physical properties. In this work, La and Mn co-doped BFO thin films with compositions BiLa(FeMn)O (x = 0, 0.05, 0.1, 0.15) (denoted as BLF, BLFM5, BLFM10, BLFM15, respectively) were prepared via a sol-gel technique on indium tin oxide (ITO) glass. All the films are monophasic, showing good crystallinity. The optical bandgap E was found to decrease monotonously with an increase in the Mn doping amount. Compared with other compositions, the BLFM5 sample exhibits a better crystallinity and less oxygen vacancies as indicated by XRD and XPS measurements, thereby achieving a better J-V performance. Based on BLFM5 as the light absorbing layer, the ITO/ZnO/BLFM5/Pt and ITO/ZnO/BLFM5/NiO/Pt heterostructure devices were designed and characterized. It was found that the introduction of the ZnO layer increases both the open circuit voltage (V) and the short circuit current density (J) with V = 90.2 mV and J = 6.90 μA/cm for the Pt/ BLFM5/ZnO/ITO device. However, the insertion of the NiO layer reduces both V and J, which is attributed to the weakened built-in electric field at the NiO/BLFM5 interface.
PubMed: 38730875
DOI: 10.3390/ma17092072 -
Materials (Basel, Switzerland) Apr 2024Bi-doped sesquioxides exhibit dual emissions, marked by distinct Stokes shift and bandwidth, meaning unraveling their underlying origins is particularly intriguing. In...
Bi-doped sesquioxides exhibit dual emissions, marked by distinct Stokes shift and bandwidth, meaning unraveling their underlying origins is particularly intriguing. In this study, we employ first-principles calculations to investigate the luminescence mechanisms within the O:Bi ( = Sc, Y, Gd, Lu) series, with the goal of addressing the posed inquiry. Our investigation commences with the analysis of the site occupancy and charge state of bismuth ions in the two cationic sites through formation energy calculations. Additionally, we examine the local coordination environments for various excited states of Bi dopants, including the P state and two types of charge transfer states, by evaluating their equilibrium geometric structures. The utilization of the hybrid functional enables us to obtain results of electronic structures and optical properties comparable with experiments. Importantly, the calculated energies for the 6s-6p transitions of Bi dopants in the O series align well with the observed dual-emission energies. This alignment challenges the conventional spectroscopic sense that emission bands with large Stokes shifts can be exclusively ascribed to charge transfer transitions. Consequently, the integration of experimental and theoretical approaches emerges as the optimal strategy for designing novel Bi-doped phosphors.
PubMed: 38730846
DOI: 10.3390/ma17092039 -
Nanomaterials (Basel, Switzerland) Apr 2024Halide perovskite CsBiBr (CBB) has excellent potential in photocatalysis due to its promising light-harvesting properties. However, its photocatalytic performance might...
Halide perovskite CsBiBr (CBB) has excellent potential in photocatalysis due to its promising light-harvesting properties. However, its photocatalytic performance might be limited due to the unfavorable charge carrier migration and water-induced properties, which limit the stability and photocatalytic performance. Therefore, we address this constraint in this work by synthesizing a stable halide perovskite heterojunction by introducing hydrogen titanate nanosheets (HTiO-NS, HTiO-NS). Optimizing the weight % (wt%) of CBB enables synthesizing the optimal CBB/HTiO-NS, CBHTNS heterostructure. The detailed morphology and structure characterization proved that the cubic shape of CBB is anchored on the HTiO-NS surface. The 30 wt% CBB/HTiO-NS-30 (CBHTNS-30) heterojunction showed the highest BnOH photooxidation performance with 98% conversion and 75% benzoic acid (BzA) selectivity at 2 h under blue light irradiation. Detailed optical and photoelectrochemical characterization showed that the incorporating CBB and HTiO-NS widened the range of the visible-light response and improved the ability to separate the photo-induced charge carriers. The presence of HTiO-NS has increased the oxidative properties, possibly by charge separation in the heterojunction, which facilitated the generation of superoxide and hydroxyl radicals. A possible reaction pathway for the photocatalytic oxidation of BnOH to BzH and BzA was also suggested. Furthermore, through scavenger experiments, we found that the photogenerated h, e and •O play an essential role in the BnOH photooxidation, while the •OH have a minor effect on the reaction. This work may provide a strategy for using HTiO-NS-based photocatalyst to enhance the charge carrier migration and photocatalytic performance of CBB.
PubMed: 38727346
DOI: 10.3390/nano14090752 -
Chemical Science May 2024Metal-organic frameworks (MOFs) are appealing candidate materials to design new photoelectrodes for use in solar energy conversion because of their modular nature and...
Metal-organic frameworks (MOFs) are appealing candidate materials to design new photoelectrodes for use in solar energy conversion because of their modular nature and chemical versatility. However, to date there are few examples of MOFs that can be directly used as photoelectrodes, for which they must be able to afford charge separation upon light absorption, and promote the catalytic dissociation of water molecules, while maintaining structural integrity. Here, we have explored the use of the organic linker anthraquinone-2, 6-disulfonate (2, 6-AQDS) for the preparation of MOFs to be used as photoanodes. Thus, the reaction of 2, 6-AQDS with Bi(iii) or a combination of Bi(iii) and Fe(iii) resulted in two new MOFs, BiPF-10 and BiFePF-15, respectively. They display similar structural features, where the metal elements are disposed in inorganic-layer building units, which are pillared by the organic linkers by coordination bonds through the sulfonic acid groups. We show that the introduction of iron in the structure plays a crucial role for the practical use of the MOFs as a robust photoelectrode in a photoelectrochemical cell, producing as much as 1.23 mmol H cm with the use of BiFePF-15 as photoanode. By means of time-resolved and electrochemical impedance spectroscopic studies we have been able to unravel the charge transfer mechanism, which involves the formation of a radical intermediate species, exhibiting a longer-lived lifetime by the presence of the iron-oxo clusters in BiFePF-15 to reduce the charge transfer resistance.
PubMed: 38725492
DOI: 10.1039/d4sc00980k -
Gut and Liver May 2024: Bismuth-based quadruple therapy (BQT) is a treatment option for clarithromycin-resistant (HP) infection. The aim of this study was to compare the efficacy of 7-day...
BACKGROUND/AIMS
: Bismuth-based quadruple therapy (BQT) is a treatment option for clarithromycin-resistant (HP) infection. The aim of this study was to compare the efficacy of 7-day BQT with that of 14-day BQT as first-line treatment for clarithromycin-resistant HP infection.
METHODS
: A total of 162 treatment-naïve patients with peptic ulcer disease and clarithromycin-resistant HP infection confirmed by real-time polymerase chain reaction (RT-PCR) were enrolled. The enrolled patients were prospectively randomized to receive BQT for either 7 or 14 days of treatment. Eradication of HP infection was assessed using a C-urea breath test. Eradication and adverse event rates of the two groups were assessed.
RESULTS
: The overall eradication rates in the intention-to-treat (ITT) and per-protocol (PP) analyses were 83.0% (95% confidence interval [CI], 77.2% to 88.9%; 132/159) and 89.8% (95% CI, 84.9% to 94.7%; 132/147), respectively. The eradication rates in the ITT analysis were 79.0% (64/81) in the 7-day group and 87.2% (68/78) in the 14-day group (p=0.170). The eradication rates in the PP analysis were 86.5% (64/74) in the 7-day group and 93.2% (68/73) in the 14-day group (p=0.182). Clinically significant adverse events occurred in 18.2% of patients. There was no statistically significant difference in the rates of individual or all adverse events between the two groups.
CONCLUSIONS
: Both 7-day and 14-day BQT were effective and safe as first-line therapy for HP infections identified as resistant to clarithromycin by RT-PCR. For clarithromycin-resistant HP infections, 7-day BQT may be sufficient as first-line therapy.
PubMed: 38712395
DOI: 10.5009/gnl230453 -
ACS Omega Apr 2024Traditional Chinese medicine (TCM) formula decoctions easily form nanoaggregates due to self-assembly during the decoction process. However, research on nanoaggregates...
Traditional Chinese medicine (TCM) formula decoctions easily form nanoaggregates due to self-assembly during the decoction process. However, research on nanoaggregates in TCM is still in its infancy with limited systematic studies. Maxing Shigan Decoction (MXSGT), a TCM formula, has been commonly used for the treatment of fever for thousands of years in China. This study used MXSGT as an example to investigate the antipyretic effects of MXSGT nanoaggregates (MXSGT-NAs) in its decoction, shedding light on the compatibility mechanisms of Chinese medicine. MXSGT-NAs were isolated by using high-speed centrifugation and dialysis techniques. The morphology, particle size distribution, and electrical potential of MXSGT-NAs were characterized. High-performance liquid chromatography (HPLC) was used to detect ephedrine and pseudoephedrine in MXSGT-NAs. The self-assembly mechanism of MXSGT-NAs was investigated by deconstructing the prescription. In pharmacodynamic experiments, a rat fever model was established through the subcutaneous injection of dry yeast to investigate the antipyretic effects of MXSGT-NAs. The results showed the presence of regularly shaped spherical nanoaggregates in MXSGT. It contains carbon, oxygen (O), sulfur (S), sodium, aluminum (Al), calcium (Ca), iron, magnesium, bismuth (Bi), etc. MXSGT-NAs exerted substantial antipyretic effects on febrile rats. Furthermore, we found micrometer-sized particles composed of Ca, O, S, potassium, and Bi in Shi gao decoctions. This study is the first to provide evidence for the self-assembling property of Shi gao, elucidate the scientific connotation of dispensing Shi gao in MXSGT, and provide a novel perspective for the study of TCM decoctions.
PubMed: 38708238
DOI: 10.1021/acsomega.4c00423 -
Heliyon Apr 2024Rising clarithromycin resistance undermines () treatment efficacy. We aimed to determine clarithromycin's minimum inhibitory concentration (MIC) levels and identify...
BACKGROUND
Rising clarithromycin resistance undermines () treatment efficacy. We aimed to determine clarithromycin's minimum inhibitory concentration (MIC) levels and identify specific mutation sites in the 23S ribosomal subunit (23S rRNA) that predict treatment outcomes in a 14-day regimen of clarithromycin bismuth quadruple therapy (amoxicillin 1g, clarithromycin 500 mg, rabeprazole 10 mg, and colloidal bismuth pectin 200 mg).
MATERIALS AND METHODS
We included adult patients who hadn't previously undergone clarithromycin-based treatment, either as initial or rescue therapy. Exclusions were made for penicillin allergy, recent use of related medications, severe illnesses, or inability to cooperate. Patients underwent a 14-day clarithromycin bismuth quadruple therapy. Gastric mucosa specimens were obtained during endoscopy before eradication. MIC against amoxicillin and clarithromycin was determined using the E-test method. The receiver operating characteristic (ROC) curve helped to find the optimal clarithromycin resistance MIC breakpoint. Genetic sequences of 23S rRNA were identified through Sanger Sequencing. (ChiCTR2200061476).
RESULTS
Out of 196 patients recruited, 92 met the inclusion criteria for the per-protocol (PP) population. The overall intention-to-treat (ITT) eradication rate was 80.00 % (84/105), while the modified intention-to-treat (MITT) and PP eradication rates were 90.32 % (84/93) and 91.30 % (84/92) respectively. No amoxicillin resistance was observed, but clarithromycin resistance rates were 36.19 % (38/105), 35.48 % (33/93), and 34.78 % (33/92) in the ITT, MITT, and PP populations respectively. Compared with the traditional clarithromycin resistance breakpoint of 0.25 μg/mL, a MIC threshold of 12 μg/mL predicted better eradication. Among 173 mutations on 152 sites in the 23S rRNA gene, only the 2143A > G mutation could predict eradication outcomes ( < 0.000).
CONCLUSIONS
Interpretation of elevated MIC values is crucial in susceptibility testing, rather than a binary "susceptible" or "resistant" classification. The 2143A > G mutation has limited specificity in predicting eradication outcomes, necessitating further investigation into additional mutation sites associated with clarithromycin resistance.
PubMed: 38699713
DOI: 10.1016/j.heliyon.2024.e29774