Notes

Any visible-light-induced photocatalyst-free way of C-3 dicarbonyl coumarin production.
Fentanyl and its analogs have been at the center of the opioid epidemic currently wreaking havoc in the United States. One major element in the opioid crisis is the growing number of clandestine fentanyl labs being reported by enforcement agencies. The development of new analytical methods for detecting and identifying fentanyl and its congeners is among the useful tools in our goal to limit the use of this dangerous family of narcotics. Herein we describe an analytical technique using surface-enhanced Raman spectroscopy (SERS) and a microfluidic device, for detecting fentanyl and two of its chemical precursors, despropionylfentanyl (4ANPP) and N-phenethyl-4-piperidinone (NPP). The vibrational spectra of this family of analytes are very similar, making them difficult to distinguish by traditional means. In addition to taking advantage of the sensitivity provided by SERS, we developed a chemometric approach utilizing a hierarchical partial least squares-discriminant analysis algorithm that allowed us to distinguish spectra that possess many similar features.The therapeutic effects of molecules produced by the plant species Cannabis sativa have since their discovery captured the interest of scientists and society, and have spurred the development of a multidisciplinary scientific field with contributions from biologists, medical specialists and chemists. Decades after the first isolation of some of the most bioactive tetrahydrocannabinols, current research is mostly dedicated to exploiting the chemical versatility of this relevant compound class with regard to its therapeutic potential. This review will primarily focus on synthetic pathways utilised for the synthesis of tetrahydrocannabinols and derivatives thereof, including chiral pool-based and asymmetric chemo- and biocatalytic approaches.There is growing interest in the development of simple, fast, sustainable and low-cost analytical methodologies on paper-based platforms. However, sensitive detection strategies that fit properly with these devices are still required. In this work, a calibration-free method is proposed for analytical determinations performed on paper-based electrochemical devices, in this case, for ascorbic acid. Carbon ink is deposited on a hydrophilic working area of the paper delimited with a hydrophobic wax. This maskless procedure is fast and cuts down ink waste. The connection of this working electrode to the potentiostat is provided by reusable gold-plated connector headers that provide also the reference and counter electrodes. The thickness of the paper substrate defines the electrochemical cell and confines a sample volume, ideal for thin-layer coulometry. Controlled-potential coulometry is performed applying a potential of +0.6 V for 50 s. The charge is calculated by measuring the area under the fast chronoamperogram and the concentration is determined following Faraday's law (known number of transferred electrons). This methodology was applied to the determination of ascorbic acid, with a limit of detection of 40 μM. Its concentration in commercial fruit juices can be directly determined in diluted samples. The absence of matrix effects is observed by comparing the results obtained before and after enzymatic reaction of the sample with cucumber ascorbate oxidase. Good accuracy and precision makes this method suitable for quality control of ascorbic acid in commercial juices. Underexploited coulometric readout can be applied as a fast (calibration-free) and low-cost (standards not required) transduction principle for the newly developed paper devices.BiVO4 has been widely used as a photoanode material, while the slow surface oxygen evolution reaction (OER) kinetics still severely hinders its performance. Here, an efficient bimetallic cocatalyst (named FeSnOS) was obtained by post-annealing a Fe/Sn-containing metal chalcogenide coordination compound to enhance the OER activity of BiVO4. The synergistic effect of Fe and Sn species in the amorphous FeSnOS cocatalyst efficiently lowers the interface impedance of the photoanode, reduces the electrochemical reaction overpotential, and promotes the surface OER dynamics. At the same time, a type-II heterojunction was constructed due to the process of post-annealing, which efficiently improves the bulk phase charge separation efficiency of the photoanode. The obtained optimal photoanode (named FeSnOS-BiVO4) shows a photocurrent density of 3.1 mA cm-2 at 1.23 V vs. the reversible hydrogen electrode, which is 3.4 times higher than that of the pristine BiVO4 photoanode, and its onset potential shifts negatively from 0.44 V to 0.25 V. This work presents a simple and effective method to build a bimetallic cocatalyst for improved photoelectrochemical performance, which extends the application of polymetallic metal chalcogenide complexes.Glutaryl and adipoyl chlorides undergo facile condensation with the bis(silyl)phosphanes RP(SiMe3)2 (R = Me, nBu, tBu, Ph, Mes) to afford exclusively the phosphacycloalkyldiones (CH2)n(C[double bond, length as m-dash]O)2PR (n = 3, 4). Characterised spectroscopically and, for R = Ph, Mes (n = 3) crystallographically, the macrocycles are conformationally fluxional in solution and appreciably moisture sensitive. Though seemingly resistant to chemical oxidation at phosphorus, coordination is readily achieved, as illustrated by isolation of trans-[Pt(PEt3)P(Ph)(CO)2(CH2)3Cl2] and a series of tungsten pentacarbonyl complexes, which are characterised crystallographically and by infrared and NMR spectroscopy. Together, these data suggest the macrocycles to be relatively weak σ-donors with no appreciable π-acceptor character.In this paper, we developed different three-component organic heterojunction structures supported by PET/ITO substrates with the aim to study the possible synergies and/or compromises between charge transfer (CT) and energy transfer (ET) processes in organic solar cells (OSCs). As components, we employed poly(3-hexylthiophene-2,5-diyl) (P3HT; donor), [6,6]-phenyl-C61-butyric acid methyl ester (PCBM; acceptor) and poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) that is known to give good ET to P3HT. NSC187208 At first, we observed that in a planar heterojunction (PHJ) solar cell, F8BT has to be properly located in between P3HT and PCBM to get a cascade energy level configuration allowing for a better CT and power conversion efficiency. Then, we observed that by producing a P3HTF8BT blend, the energy transfer process can be improved in the P3HTF8BT/PCBM active layer. This may enable decreasing the thickness of the active layer while maintaining a similar PCE that is very interesting for the development of transparent OSCs.
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