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The advancement of Internet of Things technology has made continuous environmental monitoring a crucial requirement for various applications. To address the issue of the network life cycle, Wireless Rechargeable Sensor Networks (WRSNs) have emerged as a promising solution. This research is focused on WRSN applications in indoor settings such as the Industrial Internet of Things and indoor greenhouses. In such scenarios, rechargeable wireless sensing devices can gather the required information, reducing equipment costs and eliminating the inconvenience of wired sensors. This study proposes the utilization of a genetic algorithm to optimize the deployment of chargers in indoor environments. Compared to greedy algorithms, this approach can determine the best solution for charger deployment and minimize deployment expenses. &nbsp

A simple electrochemical oxidation cyclization strategy for the construction of polycyclic phosphonium salts skeletons from trivalent arylphosphines was established.

Abstract: A pinacol rearrangement is a well-known reaction by which a 1,2-diol is converted to a carbonyl compound through acid-catalyzed dehydration followed by a 1,2-migration of one of the neighboring substituents. Due to the particular abilities in installing polycyclic skeletons, quaternary carbon centers, and spirocyclic cores, the pinacol rearrangement reaction is a powerful and effective means of forming carbonyl functional groups in a variety of different molecules. Moreover, the substrates with an alkene group, a furan ring or alkyl chain tethered between the two diols have also been investigated as the expansion of pinacol rearrangement. Benefiting from the continuous development of the catalysis methodologies, pinacol rearrangements demonstrate synthetic utility in the preparation of natural products, bioactive molecules, and other functionally useful compounds. In this review, we discuss recent advances in the development of pinacol rearrangement and extended pinacol rearrangement reactions catalyzed by Brønsted acid, Lewis acid, and heterogeneous catalysts. In addition, we summarize several examples use pinacol rearrangements used in the synthesis of natural products and other valuable molecules.

A supramolecular polymer was developed through the encapsulation of polypyrrole by cucurbit[6]uril (PPy@Q[6]), which was employed as the electrode material to improve the capacitor ability of conductive polypyrrole.

An innovative photoanode was developed for efficient PEC water splitting by the deposition of a Co nano-catalyst on the surface of a g-C3N4 film, producing the significant photocurrent density of 393 μA cm−2 at 1.23 V vs. RHE.

A supramolecular chiral electrode was constructed by layer-by-layer assembly of gold nanoparticles (AuNPs) and an S-chiral multifarene [3,2,1] (S-CMF) on the surface of a glassy carbon electrode, which was applied for the electroreduction of acetophenone. The host-guest encapsulation of the substrate within the chiral cavity was confirmed by 1H NMR, fluorescence titration, and molecular simulation. The composite on the electrode surface was characterized by electrochemical impedance spectroscopy (EIS) and transmission electron microscopy (TEM). Optimization of the electrolysis process was performed to give a high yield of 70.9% and high enantioselectivity of 63.9% ee, which exhibited superior reactivity to the previously reported materials. The repeatability of the experiment was tested via five separate experiments and indicated consistent stability, recyclability, and reusability of the novel chiral electrode. The proposed mechanism involved supramolecular encapsulation, two single-electron transfer steps, and proton addition. The chiral electroorganic reduction was extended to more substrates to provide successful yields and enantioselectivity.

Porous materials, especially metal-organic frameworks, covalent organic frameworks, and supramolecular organic frameworks, are widely used in heterogeneous catalysis, adsorption, and ion exchange. Cucurbit[n]urils (Q[n]s) suitable building units for porous materials because they possess cavities with neutral electrostatic potential, portal carbonyls with negative electrostatic potential, and outer surfaces with positive electrostatic potential, which may result in the formation of Q[n]-based supramolecular frameworks (QSFs) assembled through the interaction of guests within Q[n]s, the coordination of Q[n]s with metal ions, and outer-surface interaction of Q[n]s (OSIQ). This review summarizes the various QSFs assembled via OSIQs. The QSFs can be classified as being assembled by 1) self-induced OSIQ, 2) anion-induced OSIQ, and 3) aromatic-induced OSIQ. The design and construction of QSFs with novel structures and specific functional properties may establish a new research direction in Q[n] chemistry.

A supramolecular strategy was developed for electrocatalytic water splitting in the presence of a macrocyclic compound. The improvement in the oxygen evolution reaction (OER) was observed on the surface of an electrode modified via the facile layer-by-layer assembly of polypyrrole (PPy), reduced graphene oxide (rGO) and cucurbit[6]uril (Q[6]) in sequence. The electrochemical performance was evaluated, and the results indicate the remarkable activity of the proposed supramolecular electrocatalyst toward the OER in alkaline media. The morphology and chemical structure of the electrocatalyst were estimated before and after the OER process. Linear sweep voltammetry measurements suggested that a current density of 10 mA cm−2 at an overpotential of 377 mV was achieved, which is very close to the value of IrO2 under the same conditions, and the calculated Tafel slope of 167 mV dec−1 and electrochemical impedance spectroscopy results imply that a fast charge transfer occurs on the electrode with the functionalization of Q[6]. The developed catalyst could be considered as a potential alternative material for high-efficiency electrocatalytic OER.

An electrochemiluminescence (ECL) sensor based on a benzo[3]uril-modified glassy carbon electrode with sensitized luminescence, with the coexistence of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) as the coreactant, was successfully constructed. The sensitization mechanism was proposed by analyzing the results of the control experiments for establishing the relationship of the luminescence effect with the concentration of HEPES. Under the optimized conditions, the fabricated sensor system was applied for the detection of Fe3+ in an aqueous solution with good sensitivity and selectivity. A low detection limit of 0.41 nM was achieved, indicating superior sensor performance over the previous analytical methods. The ECL sensor system was employed for the detection of Fe3+ in human serum samples to produce excellent recoveries ranging from 96.17% to 101.81%.

To predict how many consumers will buy goods in the next month helps the e-commerce platform discover potential buyers and carry out the corresponding strategic activities. After analyzing and cleaning the data, we select user purchase features to use eXtreme Gradient Boosting (XGBoost) algorithm to train the divided data sets. Meanwhile, we choose Light Gradient Boosting Machine (LightGBM), Long Short-Term Memory (LSTM) and Fully Connected Neural Network (FCNN) as comparison algorithms. Expectedly, the experiments indicate that using the XGBoost algorithm to predict purchasing can improve performance. Specifically, LightGBM and LSTM increase significantly before remaining stable, whereas FCNN begins in the highest number falling dramatically to approximately the accuracy of 0.32 and keeps steady. Throughout the iteration process, the accuracy of XGBoost surpassed FCNN, and experienced a moderate increase from 0.55 to 0.67, increasing the accuracy by 12%.

Electrochemical sensing is a promising analytic method with its advantages, such as low cost, fast response, simple operation, high accuracy, low detection limit and so on. With the rapid development of electroanalysis, various modified electrodes were synthesized for constructing different kinds of electrochemical sensors on purpose. Macrocyclic compounds with their superior supramolecular recognition properties have aroused the research interest, as they can be used as modifiers for enhancing the sensitivity and selectivity of electrodes. All five classic macrocyclic compounds, which are crown ethers, cyclodextrins, calixarenes, cucurbiturils, and pillararenes, have been employed as receptors for electrochemical sensors, and these macrocycles have led to a wilder detection range, a lower detection limit, and superior ability of anti-interferences against coexisting ions or molecules. The macrocycles modified electrodes have shown greater sensitivity and selectivity in detection. Therefore, this review focuses on the results of the studies published in recent 8 years on macrocycles improved electrochemical sensing. In this review, the recent development of functionalization of macrocyclic compounds including crown ethers, cyclodextrins, calixarenes, cucurbiturils, pillararenes, on electrochemical sensors has been summarized.

Fluorescent chemosensors based on a new macrocyclic compound, multifarene[2,2], with modification by triazole-linked pyrene or anthracene were synthesized. These macrocyclic sensors exhibited high affinity and selectivity toward Ag+ over other metal ions, with ratiometric or enhanced response of their fluorescence emissions depending upon the substituent species for coordination to Ag+, and an unexpected response to a concentration threshold of the metal cations was discovered. The experimental evidences of fluorescence spectra, 1H NMR titration, IR spectra, and high-resolution mass spectra suggested the coordination behaviors of the sensors with Ag+, that is, the 1:1 complexes were formed with moderate association constants of about 105 L·mol−1, and the sulfur atoms on macrocyclic ligand should affinite to the metal cations. Energy-minimized structures and frontier orbitals were estimated by quantum chemical calculations with a view to rationalizing the fluorescence response of the multifarene[2,2] sensors upon binding to Ag+.

Organophosphate esters (OPs) are substitutes for polybrominated diphenyl ether (PBDE) flame retardants. China is the largest producer of OPs globally, with the production rate increasing at 15% annually. Since some OPs are neurodevelopmental and/or carcinogenic toxicants, human exposure is a concern. In this study, concentrations of eight OP metabolites (mOPs) were measured in human urine samples collected from 13 cities located in Northern, Eastern, Southern, and Southwestern China. All target mOPs were frequently detected with detection rates of 50% to 100%, indicating widespread human exposure to OPs. Bis(2-chloroethyl) phosphate (BCEP; median: 0.68 ng/mL), bis(1-chloro-2-propyl) phosphate (BCIPP; 0.30 ng/mL), diphenyl phosphate (DPHP; 0.30 ng/mL), and dibutyl phosphate (DBP; 0.29 ng/mL) were the dominant mOPs across all participants. Regional differences in concentrations (ΣmOPs varied from 0.86 to 3.7 ng/mL) and composition profiles (contribution of chlorinated mOPs to ΣmOPs varied from 35% to 95%) of mOPs were observed within China. In comparison to the concentrations reported worldwide, urinary DPHP and bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) levels in China were lower, whereas BCEP and DBP levels were comparable or higher. The total daily intake (TDI) of tris(2-chloroethyl) phosphate (TCEP), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and triphenyl phosphate (TPHP) were estimated from daily urine excretion rate and the fraction of OP metabolized in human liver microsomes (TDIHLM) or S9 fraction (TDIS9). The intake estimates showed that Chinese residents were exposed to TCEP from 96.9 to 46,700 (or 52.2 to 25,200) ng/kg bw/day. Depending on the reference dose, we found that approximately 5% of the individuals exceeded the limit (i.e., 2200 ng/kg bw/day) for TCEP intake. To our knowledge, this is the first nationwide baseline survey to determine urinary levels of mOPs in Chinese residents. Keywords: Organophosphate esters, Urinary levels, Total daily intake, Health risk

An electrochemiluminescence (ECL) sensor based on a benzo[3]uril-modified glassy carbon electrode with sensitized luminescence, with the coexistence of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) as the coreactant, was successfully constructed. The sensitization mechanism was proposed by analyzing the results of the control experiments for establishing the relationship of the luminescence effect with the concentration of HEPES. Under the optimized conditions, the fabricated sensor system was applied for the detection of Fe

Multiple photoluminescence, involved in monomer emission, excimer emission and charge transfer emission origin from new pyrene-fused hexaarylbenzenes (HAB) compounds were observed, which were designed and synthesized (in high yield) via the Diels-Alder reaction of bis(2-tert-butylpyren-6-yl)acetylene and tetraphenylcyclopentadienone. Although the distinction of between two molecules arises only from the geometrical position of one of the pyrenes, the NMR spectra, the crystal packing and the physicochemical properties of these pyrene-based HAB hybrids are distinctly different both in their solution state and in aggregation-state. The X-ray diffraction analysis clearly indicated that the pyrene moieties in this system would form different crystal packing in crystal state that can induce a fantastic multiple photoluminescence phenomenon.

A selective and sensitive fluorescent chemosensor based on an anthracene-functionalized triazole-linked multifarene[2,2] was successfully synthesized and investigated with regard to the recognition of metal ions using fluorescence spectroscopy, 1H NMR titration, and IR spectroscopy. The proposed sensor exhibited desirable properties for potential fluorescence enhanced chemosensor applications, including selective affinity and low Zn2+ and Cd2+ detection limits compared with other metal ions. Quantum chemical calculations described the synthesized chemosensor's static structure and its coordination to Zn2+ and Cd2+. Frontier molecular orbital distribution and energy changes suggested a possible mechanism for increased receptor fluorescence intensity with Zn2+ and Cd2+ addition.

Carboxymethyl-substituted and ester-substituted benzo[3]urils have been successfully synthesized and investigated with regard to the supramolecular recognition of inorganic ions by means of fluorescence spectroscopy, 1H NMR spectrometry, and quantum chemical calculations. The results indicated that benzo[3]uril 4 bearing six carboxyl groups binds to Cu2+, Fe3+, F−, and CH3COO− with strong affinities. Moreover, this macrocyclic host could be used to recognize ion pairs comprising Cu2+ and CH3COO−, Cu2+ and F−, Fe3+ and CH3COO−, and Fe3+ and F− through its fluorescence response. In contrast, benzo[3]uril 3, bearing ester groups, showed only host–guest interactions with Cu2+ and Fe3+. The absence of binding of the macrocycle 3 to anions highlights the important role of the carboxyl groups on benzo[3]uril 4, which provide active protons to form hydrogen bonds between the host and anion guests.

Fluorescence spectroscopy, 1H NMR spectroscopy and quantum chemical calculations were used to investigate the interactions of benzo[6]urils with polycyclic aromatic hydrocarbons acting as the guest molecules. The fluorescence emission of the host was decreased upon the addition of an increasing amount of the guest molecules, providing an association constant in the range of 8.0 × 102–7.5 × 104 L mol−1 obtained via non-linear curve fitting, and the formation of host–guest complexes in a 1 : 1 ratio was confirmed using Job's plot analysis. In addition, the 1H NMR spectra also supported the formation of the interaction complexes with changes in the chemical shifts of the aromatic protons in the host molecules being observed in the presence of the guest molecules. The calculation results provided the structures of the encapsulation complexes with the driving force attributed to the formation of hydrogen bonds between the benzo[6]urils host and the guest molecules. The unique property of luminescence with electrochemical reaction was discovered in methyl-substituted benzo[6]uril, which has great potential as a new type of electrochemiluminescent material.