Prediction and realisation of high mobility and degenerate p-type conductivity in CaCuP thin films

Phosphides are interesting candidates for hole transport materials and p-type transparent conducting applications, capable of achieving greater valence band dispersion than their oxide counterparts due to the higher lying energy and increased size of the P 3p orbital. After computational identification of the indirect-gap semiconductor CaCuP as a promising candidate, we now report reactive sputter deposition of phase-pure p-type CaCuP thin films. Their intrinsic hole concentration and hole mobility exceed 1 × 10²⁰ cm⁻³ and 35 cm² V⁻¹ s⁻¹ at room temperature, respectively. Transport calculations indicate potential for even higher mobilities. Copper vacancies are identified as the main source of conductivity, displaying markedly different behaviour compared to typical p-type transparent conductors, leading to improved electronic properties. The optical transparency of CaCuP films is lower than expected from first principles calculations of phonon-mediated indirect transitions. This discrepancy could be partly attributed to crystalline imperfections within the films, increasing the strength of indirect transitions. We determine the transparent conductor figure of merit of CaCuP films as a function of composition, revealing links between stoichiometry, crystalline quality, and opto-electronic properties. These findings provide a promising initial assessment of the viability of CaCuP as a p-type transparent contact.

We synthesize air-stable, p-type CaCuP thin films with high hole concentration and high hole mobility as potential p-type transparent conductors. We study their optoelectronic properties in detail by advanced experimental and computational methods.     

Crotonic,cynnamic, and propiolic acids motifs in the synthesis of thiopyrano[2,3-d][1,3]thiazoles via hetero-Diels–Alder reaction and related tandem processes

Various novel thiopyrano[2,3-d][1,3]thiazol-2-one-6-carboxylic acids derivatives were synthesized in 54–86% yields via hetero-Diels–Alder reactions and related acylation-based tandem processes of 5-arylidene-4-thioxo-2-thiazolidinones with crotonic, propiolic, and cynnamic acids derivatives. Stereo- and regioselectivity of cycloaddition were investigated.     

Anticancer Aminoferrocene Derivatives Inducing Production of Mitochondrial Reactive Oxygen Species

Elevated levels of reactive oxygen species (ROS) and deficient mitochondria are two weak points of cancer cells. Their simultaneous targeting is a valid therapeutic strategy to design highly potent anticancer drugs. The remaining challenge is to limit the drug effects to cancer cells without affecting normal ones. We have previously developed three aminoferrocene (AF)-based derivatives, which are activated in the presence of elevated levels of ROS present in cancer cells with formation of electron-rich compounds able to generate ROS and reduce mitochondrial membrane potential (MMP). All of them exhibit important drawbacks including either low efficacy or high unspecific toxicity that prevents their application in vivo up to date. Herein we describe unusual AF-derivatives lacking these drawbacks. These compounds act via an alternative mechanism: they are chemically stable in the presence of ROS, generate mitochondrial ROS in cancer cells, but not normal cells and exhibit anticancer effect in vivo.     

Arginine-hydrolyzing enzymes for electrochemical biosensors

Since l-Arginine (Arg) is a semi-essential amino acid for humans, its adequate amount must be consumed in the diet to prevent certain negative consequences related to insufficient synthesis of this amino acid under specific physiological conditions. Arg metabolism results in the production of a biochemically diverse range of such products as urea, some amino acids, creatine, polyamines, nitric oxide, etc. Arg, an important biomarker in clinical diagnostics, is also used for prevention/treatment of different diseases, including cancer and COVID-19. Furthermore, it serves as an indicator of food and beverages quality.A variety of optic and electrochemical methods for Arg determination have already been suggested. The biosensor systems based on the enzymes of Arg metabolism were shown to be the most promising tools for Arg assay. This review focuses on the peculiarities of electrochemical biosensors for Arg assay based on the use of Arg-degrading enzymes and on the analysis of their advantages as compared to other approaches.     

Third Generation Buchwald Precatalysts with XPhos and RuPhos: Multigram Scale Synthesis,Solvent-Dependent Isomerization of XPhos Pd G3 and Quality Control by 1H- and 31P-NMR Spectroscopy

The third generation Buchwald precatalysts Pd(ABP)(Phos)(OMs) (also known as Phos Pd G3)) with XPhos and RuPhos were prepared in multigram scale by a modified procedure (ABP = fragment of C-deprotonated 2-aminobiphenyl, XPhos = 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl, RuPhos = 2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl, OMs⁻ = CH₃SO₃⁻). The ¹H- and ³¹P-NMR spectra of the title complexes and some impurities, measured by various 1D and 2D techniques, were analyzed in detail. The solvent-dependent isomerization of Pd(ABP)(XPhos)(OMs) was studied by NMR, and the X-ray structures of two isomers were determined. The impurities in precatalysts, such as Pd(ABP)(HABP)(OMs) (HABP—neutral 2-aminobiphenyl coordinated to Pd²⁺ in N-monodentate mode) and PdCl₂(XPhos)₂, were identified and characterized by single crystal X-ray diffraction. A simple method for the quick quality control (QC) of the precatalysts, suitable for routine use, was proposed. The method was based on the assessment of the impurity content on the basis of the ¹H-NMR spectra analysis.     

Monitoring chemotherapeutic response in RIF-1 tumors by single-quantum and triple-quantum-filtered (23)Na MRI, (1)H diffusion-weighted MRI and PET imaging

The effects of 5-fluorouracil (5FU, 150 mg/kg, ip) on subcutaneously implanted radiation-induced fibrosarcoma (RIF-1) tumors were monitored by in vivo (1)H MRI to evaluate the water apparent diffusion coefficient (ADC), by single-quantum (SQ) and triple-quantum-filtered (TQF) (23)Na MRI to evaluate compartmental Na(+) content and by positron emission tomography (PET) to evaluate 2-[(18)F]fluoro-2-deoxy-d-glucose (FDG) uptake in the tumor. The MRI experiments were performed on untreated control and treated mice once before and then daily for 3 days after treatment. The PET experiments were performed on separate groups of age- and tumor-volume-matched animals once before and then 3 days after treatment. Tumor volumes significantly decreased in treated animals 2 and 3 days posttreatment. At the same time points, in vivo MRI measurements showed an increase in both total tissue SQ (23)Na signal intensity (SI) and water ADC in treated tumors while control tumors showed no change in these parameters. TQF (23)Na SI and FDG uptake were significantly lower in treated tumors compared with control tumors 3 days after 5FU treatment. The correlated increases in total tissue (23)Na SI and water ADC following chemotherapy reflect an increase in extracellular space, while the lower TQF (23)Na SI and FDG uptake in treated tumors compared with control tumors suggest a shift in tumor metabolism from glycolysis to oxidation and/or a decrease in cell density.     

Copper(II)–lanthanide(III) 15-metallacrown-5 complexes based on pyrazinohydroxamic acid as new multiple-binding pentagonal platforms with Lewis amphoteric nature

Reaction of copper(II) acetate, lanthanium(III) or gadolinium(III) nitrate (1/5 equiv.) with pyrazinohydroxamic acid (H₂Pyzha) in DMF led to a series of new heterobimetallic 15-metallacrown-5 complexes. In a MeOH/H₂O solution the complexes exist as molecular unassociated metallacrowns. In solid state their structures are more complicated as it has been confirmed by X-ray analysis: discrete molecular metallacrowns [Gd(NO₃)₂{Cu(pyzha)}₅(DMF)₄(NO₃)] · 0.5C₆H₆ · H₂O (1), [Gd(NO₃)₂{Cu(pyzha)}₅(DMF)₅](NO₃) · 1.5DMF · 0.5H₂O (2), [La(NO₃)₂{Cu(pyzha)}₅(DMF)₅]NO₃ · 1.5DMF · 2C₆H₆ (3) are solvates, whereas compound [{La(NO₃)₂{Cu(pyzha)}₅(DMF)₅}₂(μ²-NO₃)](NO₃) · 3DMF (4) is a dimer, where μ-bridged nitrate links two copper centres of the adjacent metallamacrocycles. Complex [Gd(NO₃)₂{Cu(pyzha)}₅(DMF)₂(H₂O)(NO₃)] · CH₂Cl₂ · DMF (5) self-associates into a polymer chain by means of one pyrazine moiety and the copper ring atom. Reaction of the molecular metallacrowns with excess of inorganic salts CdBr₂ or Cu(OAc)₂ proceeds as anion methathesis process affording heteroanionic metallacrowns: molecular [Gd(NO₃)₂{Cu(pyzha)}₅(DMF)₅] [Gd(NO₃)₂{Cu(pyzha)}₅(DMF)₄(H₂O)][CdBr₄] · 1.5DMF (6), and 3D hydrogen bonded polymer [La(μ²-OAc)(H₂O)₃{Cu(pyzha)}₅ (H₂O)₄(NO₃)](NO₃) · 4H₂O (7).     

Pimprinols A–C,from the terrestrial actinomycete,Streptomyces sp.

A Streptomyces sp. Lv3-13, isolated from the rhizosphere soil of the plant Mespilus germanica, has yielded three new pimprinine derivatives, named pimprinols A–C (1–3) and the unknown (2-aminophenyl)(2-ethyloxazol-5-yl) methanone (4) along with the known compounds 2-ethyl oxazole pimprinine and 2-propyl oxazole pimprinine. The structures of the compounds were elucidated based on spectroscopic methods including UV, HR-ESIMS and 1D, 2D NMR data. Compounds 1–4 were screened for antimicrobial and cytotoxic activities.     

Light emission from nanocrystalline silicon clusters embedded in silicon dioxide: Role of the suboxide states

Silicon clusters embedded in a silicon dioxide matrix were prepared by ultrasound-assisted implantation resulting in a modified concentration of suboxide states as revealed by high-resolution photoelectron spectroscopy. It is suggested that ultrasound treatment results in formation of different interface structure between silicon cluster and silicon dioxide matrix which is characterized by a distinctly reduced concentration of the suboxide states. It is observed that photoluminescence properties are strongly correlated with the concentration of the suboxide states thereby providing an evidence that besides a quantum confinement effect a closer look at the chemical composition of the nc-Si/SiO₂ system is important.