P-type metal oxides, and in particular NiO, are typically used as hole accepting layers in dye-sensitized photocathodes. Delafossites (CuMO2) with M=B, Al, Cr or Ga have recently been proposed as attractive substitutes for NiO, with theoretically a higher hole mobility than NiO, and therefore allowing a higher efficiency when the photocathode is applied in solar to fuel devices. We have experimentally validated the photoelectrochemical performance of photocathodes consisting of nanoporous CuBO2 (CBO) on Fluorine-doped Tin Oxide substrates, photosensitized with a light absorbing P1 dye. Femtosecond transient absorption and time-resolved photoluminescence studies show that light-induced hole injection occurs from the P1 dye into the CBO in a few ps, comparable to the time constant observed for NiO-based photocathodes. Importantly, the CBO-based photocathode shows significantly slower charge recombination than the NiO-based analogue. These results illustrate the promise of CBO as a p-type semiconductor in solar energy conversion devices.
Monthly Archives: September 2023
Trans‐N‐alkylation Covalent Exchanges on 1,3,4‐Trisubstituted 1,2,3‐Triazolium Iodides
1,3,4-Trisubstituted 1,2,3-triazolium salts having either aliphatic or benzylic substituents at the N-1 and N-3 positions were synthesized in two steps involving: i) copper(I) catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC), and ii)N-alkylation of the 1,2,3-triazole intermediates. Trans-N-alkylation reactions in bulk and in the presence of excess methyl iodide were monitored by 1H NMR spectroscopy for each 1,2,3-triazolium molecular model. By assigning the different formed species and their respective evolution with time, it was possible to conclude that trans-N-alkylation exchange reactions are significantly faster for benzylic substituents than for aliphatic ones. Furthermore, the exchange reactions are noticeably faster at the N-3 position than at the N-1 position most likely due to the steric hindrance induced by the neighboring C-4 substituent. The kinetics of trans-N-alkylation reactions are thus influenced by both the chemical nature of the N-1 and N-3 substituents and the regiochemistry of the 1,2,3-triazolium group. This provides important structural design rules to improve the properties of thermosetting covalent adaptable networks involving trans-N-alkylation of 1,2,3-triazolium salts.
Design, Synthesis of Novel 1,2,3‐Triazole Pendent Quinazolinones and their Cytotoxicity Against MCF‐7 Cell Line
A library of 6-(((1-(substitutedphenyl)-1H-1,2,3-triazol-4-yl)methyl)amino)-3-methylquinazolin-4(3H)-one analogues synthesized from Isatin precursor through a series of nitration, reduction, hydrolysis, cyclization and click reaction. The structures of compounds were characterized by spectral data including IR, 1H NMR, 13C NMR and Mass. The novel quinazolinone – 1,2,3-triazoles were screened for their cytotoxicity against the human breast adenocarcinoma cell lines MCF-7 by MTT assay. 4-Isopropyl and 2-bromo substituted analogues executed high activity against MCF-7 cell line with IC50 value of 10.16±0.07 µM and 11.23±0.20 µM compared to the Doxorubicin whose IC50 value is 10.81±0.03 µM. The activity of remaining compounds is good to moderate. Further, the molecular docking studies against the crystal structure of Epidermal Growth Factor Receptor delivered the best binding energies and the interactions such as H-bond and hydrophobic are inevitable. The predicted pharmacokinetic properties results showed that these compounds have more drug likeness properties.
Covalent Triazine Framework Nanosheets: Synthesis and Energy Conversion and Storage
Comprehensive Summary
Covalent triazine framework nanosheets (CTF NSs), an emerging class of two-dimensional nanomaterials, have received great attention due to their abundant active sites, permanent porosity, molecular structural diversity, superior chemical/thermal stability, and short charge diffusion path, enabling technological breakthroughs in a myriad of applications. The forefront developments and applications of CTF NSs as photocatalysts and electrochemical electrodes have conferred superior performance and made great impact in the field of energy and advanced catalysis. This forward-looking review aims to summarize the research trends, synthesis, properties of CTF NSs and their CTF counterpart, and highlight their progress in applications with respect to energy storage and conversion devices. Finally, the current challenges and future perspectives for CTF NSs are also presented.
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Gel biopolymer electrolytes based on saline water and seaweed to support the large‐scale production of sustainable supercapacitors
Climate change and the demand for clean energy have challenged scientists worldwide to produce/store more energy to reduce carbon emissions. This work proposes a conductive gel biopolymer electrolyte to support the sustainable development of high-power aqueous supercapacitors. The gel uses saline water and seaweed as sustainable resources. Herein, a biopolymer agar‒agar, extracted from red algae, is modified to increase gel viscosity up to 17-fold. This occurs due to alkaline treatment and an increase in the concentration of the agar‒agar biopolymer, resulting in a strengthened gel with cohesive superfibres. The thermal degradation and agar modification mechanisms are explored. The electrolyte is applied to manufacture sustainable and flexible supercapacitors with satisfactory energy density (0.764 W h kg-1) and power density (230 W kg-1). As an electrolyte, the aqueous gel promotes a long device cycle life (3500 cycles) for 1 Ag-1, showing good transport properties and low cost of acquisition and enabling the supercapacitor to be manufactured outside a glove box. These features decrease the cost of production and favor scale-up. To this end, this work provides eco-friendly electrolytes for the next generation of flexible energy storage devices.
Recent progress in all‐solution‐processed organic solar cells
Comprehensive Summary
All-solution-processed organic solar cells (OSCs) (from the bottom electrode to the top electrode) are highly attractive thanks to their low cost, lightweight and high-throughput production. However, achieving highly efficient all-solution-processed OSCs remains a significant challenge. One of the key issues is the lack of high-quality solution-processed electrode systems that can replace indium tin oxide (ITO) and vacuum-deposited metal electrodes. In this paper, we comprehensively review recent advances in all-solution-processed OSCs, and classified the devices as the top electrode materials, including silver nanowires (AgNWs), conducting polymers and composite conducting materials. The correlation between electrode materials, properties of electrodes, and device performance in all-solution-processed OSCs is elucidated. In addition, the critical roles of the active layer and interface layer are also discussed. Finally, the prospects and challenges of all-solution-processed OSCs are presented.
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Ambient Temperature, Metal‐Free, CDI‐Mediated Ex‐Situ Conversion of Acids to Amides: Useful Late‐Stage Strategy
An efficient ex-situ method for the amidation of carboxylic acids mediated by CDI has been disclosed herewith. This metal-free strategy is performed at ambient temperature and can be applied effectively for late-stage modification of amino acids and APIs.
The verification of delta SCF and Slater’s transition state theory for the calculation of core ionization energy
Core ionization energies (IE) are accurately estimated using ΔSCF and Slater's transition state (STS). The small remaining errors come mainly from self-interaction error and can be corrected with the “shifted STS (1)” and “shifted STS (2)” methods, thus providing a convenient means for predicting core IE.
Abstract
The core ionization energies of second- and third-period elements of the molecules C2H5NO2, SiF4, Si(CH3)4, PF3, POF3, PSF3, CS2, OCS, SO2, SO2F2, CH3Cl, CFCl3, SF5Cl, and Cl3PS are calculated by using Hartree-Fock (HF), and Kohn-Sham (KS) with BH&HLYP, B3LYP, and LC-BOP functionals. We used ΔSCF, Slater's transition state (STS), and two previously proposed shifted STS (1) and shifted STS (2) methods, which have been developed. The errors of ΔSCF and STS come mainly from the self-interaction errors (SIE) and can be corrected with a shifting scheme. In this study, we used the shifting parameters determined for each atom. The shifted STS (1) reproduces ΔSCF almost perfectly with mean absolute deviations (MAD) of 0.02 eV. While ΔSCF and STS vary significantly depending on the functional used, the variation of shifted STS (2) is small, and all shifted STS (2) values are close to the observed ones. The deviations of the shifted STS (2) from the experiment are 0.24 eV (BH&HLYP), 0.19 eV (B3LYP), and 0.23 eV (LC-BOP). These results further support the use of shifted STS methods for predicting the core ionization energies.
In silico analysis and verification of critical genes related to vascular calcification in multiple diseases
Abstract
Identifying a functional molecular therapeutic target of vascular calcification (VC) that will not affect normal osteogenic differentiation is a challenge. To address this aim, we screened the differentially expressed genes (DEGs) in different VC conditions, including endothelial-osteogenic transition (EOT) (GSE167962), chronic kidney disease (CKD), and atherosclerosis (AS) (GSE159832). KEGG pathways, protein–protein interactions, and hub genes were also analyzed. The intersecting DEGs among the EOT, CKD, and AS groups were verified by quantitative reverse transcription polymerase chain reaction and immunohistochemistry in a DOCA-salt hypertension mouse model. The phosphoinositide 3-kinase–protein kinase B signaling pathway, ECM-receptor interaction, chemokine signaling pathway, and focal adhesion were enriched in EOT and AS-induced VC. ECM-receptor interaction, PPAR signaling pathway, apelin signaling pathway, AMPK signaling pathway, adipocytokine signaling pathway, and cholesterol metabolism were enriched in CKD and AS-induced VC. C4b, Cebpa, Lyz2, and Spp1 were also upregulated in EOT, CKD, AS, and hypertension. This study identified promising molecular targets for VC therapy.
Transforming growth factor β1 upregulates 6‐phosphofructo‐2‐kinase/fructose 2,6‐bisphosphatase‐4 expression in A549 and MCF‐10A cells
Abstract
Transforming growth factor β1 (TGFβ1) induces a cellular process known as epithelial–mesenchymal transition (EMT) associated with metabolic reprogramming, including enhanced glycolysis. Given the involvement of 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase (PFKFB) enzymes in glycolysis, we aimed to investigate whether TGFβ1 regulates expressions of PFKFB genes and if PFKFBs are required for TGFβ1-driven phenotypes. A549 and MCF-10A cell lines were used as TGFβ1-driven EMT models. Messenger RNA expressions of PFKFB and EMT genes were determined by real-time quantitative polymerase chain reaction. A small interfering RNA approach was used to deplete PFKFB4 expression. A Matrigel invasion assay was conducted to assess the effect of PFKFB4 silencing on the TGFβ1-enhanced invasion of A549 cells. F2,6BP levels were analyzed using an enzyme-coupled assay. Glucose and lactate concentrations were determined using colorimetric assays. TGFβ1 robustly induced expression of the fourth isoform of PFKFBs, PFKFB4, in both cell lines. PFKFB4 depletion partially inhibits mesenchymal transdifferentiation caused by TGFβ1 in A549 cells, as assessed by microscopy. Inductions of Snail in MCF-10A cells and Fibronectin in A549 cells and repressions of E-cadherin in both cell lines by TGFβ1 are attenuated by PFKFB4 silencing. PFKFB4 silencing reduces F2,6BP and glycolytic activity, although TGFβ1 alone does not affect these parameters. Finally, PFKFB4 depletion suppresses the TGFβ1-driven invasion of A549 cells through Matrigel. Presented data suggest that TGFβ1 induces the expression of PFKFB4 in A549 and MCF-10 cells, and PFKFB4 may be required for TGFβ1-driven phenotypes such as EMT and invasion in these models.