Search

Science identity, encompassing perceptions of competence, interest, and recognition in science, alongside learning self-efficacy reflecting confidence to master science skills, are key drivers of outcomes. However, developmental patterns likely vary across contexts. Participants were 512 Chinese students spanning grades 1-3 who completed the Science Identity Scale and Science Learning Self-Efficacy Scale, with physics, chemistry, and biology achievement scores gathered. A Partial Least Squares Structural Equation Model assessed relationships. Results substantiated psychometrics for motivational measures. The model indirectly predicting achievement via first-order discipline-specific paths explained more variance than direct second-order effects. Effects significantly varied across groups stratified by grade and region. Interest and conceptual knowledge drove physics and chemistry success, while higher-order skills enhanced biology achievement overall. However, relationships differed within subgroups, suggesting personalized motivational support needs--self-belief/competence foundations for struggling learners, conceptual development for those with high prior achievement, and intrinsic enrichment for disinterested students. Results detail complex motivational profiles underlying science achievement requiring tailored identity safety and self-efficacy scaffolding alongside conceptual and skill-building for excellence across scientific disciplines. Motivational support systems may spur more equitable and optimal science outcomes among diverse adolescent learners.

This paper aimed to examine the changes in the representations of nature of science (NOS) in Chinese senior high school chemistry textbooks under the influence of the new curriculum ideas. The study was conducted based on an analytical framework in which the aspects of NOS, the approaches to address NOS, and the content relation of NOS aspects were involved. Two series of the new and old chemistry textbooks of required course modules were selected as analysis targets. The results revealed that chemistry textbooks paid more attention to classical views of NOS than contemporary views of NOS. The aspects of NOS were unevenly presented in different chapters of textbooks. The new textbooks covered the NOS aspects more comprehensively and frequently than the old ones. Regarding the approaches, the implicit approach was dominant. Compared with old ones, the proportions of the explicit-reflective and historical-explicit-reflective approaches have increased in new textbooks, but were still not high. Lastly, the content relation of NOS aspects were more of content-embedded than content-generic both in new and in old textbooks. At the end of this paper, the implications of the findings and the suggestions for the further studies were discussed.

The diversity of scientific methods has received increasing attention in the field of science education. This paper aimed to investigate how preservice chemistry teachers perceive scientific methods and their diversity. Based on the theoretical framework of Brandon's Matrix and previous research, two tasks (i.e., Task 1 "understanding of the components of Brandon's Matrix" and Task 2 "views on the diversity of scientific methods") and follow-up interview questions were developed in this study as research instruments. 130 preservice chemistry teachers from two universities in China were selected as participants. The statistical results of the questionnaire survey revealed that the participants showed a relatively satisfactory understanding of the components of Brandon's Matrix, and they judged the hypothesis testing more accurately than variable manipulation. However, the majority of participants held relatively naive views on the diversity of scientific methods, suggesting that they endorsed the idea of "the scientific method". Moreover, it was found by in-depth interviews that four typically held reasons led to the misunderstanding of scientific methods by preservice chemistry teachers, namely, misinterpreting the liberal meaning of item scenarios, misconceptions in identifying the "variable manipulation", grade disparity in the scientificity, and past learning experience in chemistry. At the end of this paper, the implications of the findings and the suggestions for further research were discussed.

Scientific methods have received widespread attention in recent years. Based on the analytical framework derived from Brandon's matrix consisting of four categories of scientific methods, this paper aims to conduct a content analysis to examine how the diversity of scientific methods is represented in college entrance chemistry examination papers from three exam boards in China. It was found that the percentages of the four categories of scientific methods in the examination papers varied significantly from each exam board, highlighting an imbalanced representation of scientific methods. Furthermore, among the four categories of scientific methods, non-manipulative parameter measurement (Non-MPM) accounted for the largest proportion in each examination paper, while the proportion of manipulative hypothesis testing (MHT) was very small, indicating that the practical chemistry items in China are less experimental. At the end of this paper, the implications of the findings and suggestions for further studies are discussed.

Medicinal chemistry is an integrated discipline that primarily concerns the design, discovery, synthesis, identification, and interpretation of biologically active compounds at the molecular level. To assist undergraduates in understanding the core subjects of medicinal chemistry, we introduced a closed-loop education mode combining fundamentals of theoretical and experimental aspects in an undergraduate medicinal chemistry experimental course. Since the "Antibiotics" chapter is an important component in our medicinal chemistry lecture course, the topic "design, synthesis and biological evaluation of [beta]-lactamase inhibitors" was selected to train the students' experimental skills and especially the ability to expand on their acquired learning. The whole course schemes, including course introduction, molecular design, chemical synthesis, biochemical testing, docking simulation, student presentation, and academic writing, were described. The [beta]-lactamase inhibitory activities of synthesized benzoxaborole compounds were discussed on the basis of experimental and computational results. The education experiences regarding course process assessment, teaching management, and student self-evaluation were also summarized. These practices will be useful to solidify medicinal chemistry knowledge, train experimental skills, and improve scientific research ability for undergraduates.

This research aimed to examine the impact of different factors on high school chemistry teachers' use of curriculum materials in China. The examination was conducted on a theoretical framework in which three aspects of curriculum materials and three ways of curriculum use are involved and nine factors are suggested. Through a questionnaire survey of 212 chemistry teachers, the findings included the following aspects. Firstly, the nine factors more induced teachers to supplement the teaching elements, but less affected teachers to delete the original contents in the curriculum materials. Secondly, among the nine factors, 'knowledge about students' was recognized as the core factor in the three dimensions of teaching objectives, teaching strategies, and teaching activities, whereas 'class size' was regarded as the peripheral factor in all three dimensions. 'Teaching resources' was another peripheral factor for the dimensions of teaching strategies and teaching activities. Thirdly, two factors were found to be significantly different among teachers who are in different areas of economic development: 'knowledge about students' and 'class size'. Fourthly, 'knowledge about curriculum' and 'knowledge about instructional strategies' were two factors that made significant differences in the comparison among teachers who have different years of teaching experience.

On the basis of the model of the interactive relationship between teachers and curriculum materials, this research proposed the four dimensions of the interaction of chemistry teachers with curriculum materials: 'routine use', 'scientific inquiry', 'STSE' and 'teacher learning'. An instrument with good validity and reliability was developed. Through a questionnaire survey of 208 junior high school chemistry teachers in three areas in Guangzhou, China, it was found that teachers thought they had a good interaction with curriculum materials, but the level of interaction is not very high. Teachers from different administrative areas were significantly different in the dimensions of 'STSE' and 'teacher learning'; teachers with different years of teaching experience showed significant differences in the dimensions of 'routine use', 'scientific inquiry' and 'STSE'. There was no interaction effect between the two variables of the areas and years of teaching. Designing educative curriculum materials and developing teacher training activities in terms of curriculum use are recommended to further improve teachers' ability to use curriculum materials.

This research aimed to examine the contributions of different sources in developing high school chemistry teachers' practical knowledge of teaching with practical work in China. The examination was conducted on a theoretical framework in which the conceptualization of PCK and nine sources of teachers' PCK were involved. Through a questionnaire survey of 323 chemistry teachers, the findings included the following aspects. Firstly, among the nine sources, overall, 'teaching practices', 'curriculum materials', 'classroom observations', and 'peer coaching' were recognized as the core sources, whereas 'learning experience' was regarded as the peripheral source. Secondly, for the five components of PCK of teaching with practical work, the contributions of the nine sources are different. Thirdly, three sources were found to be significantly different among teachers who have different years of teaching experience: 'pre-service training experience', 'classroom observations', and 'peer coaching'. In the last part of this paper, the implications of the findings and the suggestions for the further studies were discussed.

A comprehensive experiment for third-year undergraduate students in pharmaceutical engineering is described. Students had previously completed courses in analytical chemistry, chemistry of natural products, and bioseparation engineering and had background knowledge in purification, quantitative analysis, packed column chromatography, high-performance liquid chromatography (HPLC), thin layer chromatography (TLC), and so on. Students were arranged into groups of four to six, and each student group completed the whole experiment independently. Extracts of "Panax ginseng" stems and leaves were used as raw materials. Students used HPLC to analyze the contents of Rg1 in the raw materials and the purified products by the area normalization method and the absolute content method, respectively; students then calculated the yield. During silica gel column chromatography, TLC was used to quickly monitor the chromatographic fractions to accurately collect fractions containing Rg1. The pure Rg1 obtained was quantitatively analyzed by HPLC with an external standard method. Conducting this experiment, students can gain conceptual understanding as well as practical skills and understanding of separation techniques from the analytical level to the preparative level and from rapid qualitative monitoring to quantitative analysis.

This laboratory experiment visually demonstrates the advanced scientific concept of aggregation-induced emission (AIE) using hands-on learning methods. The experiment is divided into two parts: the first period consists of synthesis and isolation of the organic compound 2(TPA-O)-TPE using typical organic chemistry lab techniques; the second period focuses on visual demonstration of AIE properties based on micelle formation and thin-layer chromatography (TLC). By introducing a scientific concept through a classic technology, students can build on the foundation of prior understandings and experiences toward engaging new ideas. This experiment is suitable for many areas of chemistry, especially for organic chemistry, analytical chemistry, and materials chemistry.

A numerical study of two dimensional lid-driven triangular and trapezoidal cavity flow is performed via using the lattice Boltzmann method (LBM) for steady solutions. The equilateral and right-angled isosceles triangular cavity flow at Reynolds numbers, respectively, 500 and 100 is employed as the benchmark case for code validation. The isosceles right-angled triangular cavity flow is studied for Reynolds numbers sweeping from 100 to 8100. Flow topologies are captured and analyzed. The critical Reynolds number of Hopf bifurcation is predicted by calculating the perturbation decay rate. Two different geometries of right-angled isosceles trapezoidal cavities, bowl-shaped and pyramid-shaped trapezoids, are studied at Reynolds numbers 1000 and 7000. For each type of the trapezoidal cavity, a geometric parameter λ (top-line/base-line ratio) is presented to distinguish different geometries of trapezoidal cavities. The flow patterns regarding the streamlines, vortical structures, and velocity profiles are discussed. The impact of parameter λ on the fluid characteristics are investigated.

In recent years, nanomaterials have entered our daily lives via consumer products; thus, it has become increasingly important to implement activities to introduce these novel materials into chemistry curricula. Here we introduce a newly developed fluorescent nanomaterial, carbon dots, as a more environmentally friendly alternative to heavy-metal semiconductor quantum dots to be used as a model nanomaterial for experiments at multiple educational levels ranging from high school to upper-division college laboratories. These dots, which are polymeric in nature, can be made from a variety of carbon precursors and a cross-linker such as ethylenediamine. The synthesis, which involves heating in a conventional microwave, is quick and straightforward and can be carried out in typical high school chemistry laboratories. The resulting solution is fluorescent without further purification. To increase the complexity for entry-level college students, absorption and emission spectra of the carbon dot solution can be collected as an introduction to spectroscopy. In more advanced undergraduate lab courses, the quantum yield can be determined with a standard reference fluorescent material such as quinine sulfate. Atomic force microscopy or transmission electron microscopy images can also be collected to illustrate the morphology of these particles where such specialty instruments are accessible.

Paper-based microfluidic devices (µPAD) are a burgeoning platform of microfluidic analysis technology. The method described herein is for use in undergraduate and high school chemistry laboratories. A simple and convenient µPAD was fabricated by easy patterning of filter paper using a permanent marker pen. The usefulness of the device was demonstrated by determination of nitrite ion concentration employing a colorimetric assay. The results for real sample detection using this µPAD were satisfactory and show promise for use in other applications.

This paper aimed to explore how pedagogical content knowledge (PCK) of teachers influenced their adaptations of the curriculum materials of the new senior secondary chemistry curriculum, a standards-based science curriculum, in China. This study was based on the premise that the interaction of the teacher with the curriculum materials determines what happens in the classroom. An interpretive approach was adopted and five experienced chemistry teachers in four senior secondary schools participated in this study. Classroom observations and interviews were used as research methods. The data analysis revealed that there were four components of PCK that led to teachers' adaptations of curriculum materials and they were knowledge of students' understanding of science, knowledge of assessment in science, knowledge of instructional strategies, and knowledge of science curriculum. Among these four components of PCK, knowledge of students' understanding of science and knowledge of assessment in science were the factors that most influenced teachers' adaptations of curriculum materials. Furthermore, the ways that these four components of PCK influenced teachers' adaptations were different. The implications of the findings and the suggestions for the further studies were discussed in the last section of this paper.

A systematic approach to develop the teaching of instrumental analytical chemistry is discussed, as well as a conceptual framework for organizing and executing lectures and a laboratory course. Three main components are used in this course: theoretical knowledge developed in the classroom, simulations via a virtual laboratory, and practical training via experimentation. Problem-based learning and cooperative-learning methods are applied in both the classroom and laboratory aspects of the course. In addition, some reflections and best practices are presented on how to encourage students to learn actively. Overall, a student-centered environment is proposed that aims to cultivate students' practical abilities and individual talents.

The Test of Logical Thinking (TOLT) and the Group Assessment of Logical Thinking (GALT) are two of the instruments most widely used by science educators and researchers to measure students' formal reasoning abilities. Based on Piaget's cognitive development theory, formal thinking ability has been shown to be essential for student achievement in science and chemistry courses. The major difference between TOLT and GALT is two concrete items relating to conservation of mass and volume, which GALT contains over and above TOLT. The first intent of this study was to determine whether the two concrete items represent an advantage for the general chemistry population in terms of test reliability, discriminatory power, and item bias. Accordingly, TOLT and "TOLT + 2" (TOLT with the extra two concrete items) were each administered to a sample of over 900 students enrolled in first-semester general chemistry. The two concrete items were not observed to provide any advantage, and DIF analysis suggests that TOLT is tenably a less biased test. The second part of the study entailed a direct comparison between TOLT and GALT as intact instruments. GALT was found to have no advantage over TOLT in terms of reliability, discriminatory power, or potential item bias for either general chemistry or preparatory chemistry students. (Contains 4 tables and 3 figures.)

Electrochemical studies using nanometer-scaled electrodes are leading to better insights into electrochemical kinetics, interfacial structure, and chemical analysis. Various methods of preparing electrodes of nanometer dimensions are discussed and a few examples of their behavior and applications in relatively simple electrochemical experiments are given.

To understand the firing technology and the level of production of glazed tiles in the Ming Dynasty, an ultraviolet-visible-near-infrared (UV-Vis-NIR) spectrophotometer and an energy-dispersive X-ray fluorescence (XRF) spectrometer were used to systematically analyze the glaze color and chemical composition of glazed tiles unearthed from the southern area of the Bao'ensi site. The results revealed that little difference exists in the main wavelengths of the same glazed tile samples, but that the colored elements of glaze with different colors are different. Iron (Fe) is the main element that affects the color of yellow glaze; copper (Cu) is the main element that affects the color of green glaze; and the main colorants that affect the color of black glaze are Fe, Cu, and manganese (Mn). The yellow and black glaze unearthed from the southern area of the Bao'ensi site were relatively mature in terms of raw material composition and technological formula, whereas the raw material and technological formula of green glaze were not stable enough. To meet temple construction needs, workers were skilled in firing glazed tiles with different glaze color requirements, indicating that the glaze color of the glazed tiles was relatively mature at that time., Architectural glazed tile, a type of low-temperature lead-glazed pottery, is a common building material used in traditional Chinese architecture with good decorative and waterproof functions. The process of fabricating glass [...]

In this study, a fiber-packed needle trap device (NTD) was developed by packing heat-resistant fibers with a polyethylene glycol sol-gel coating into a 21-gauge, stainless steel needle. The polyethylene glycol sol-gel coating has numerous advantages, including uniform roughness and a large specific surface area. The prepared NTD was used for headspace extraction of five polychlorinated biphenyls (PCBs) in water samples, determined by gas chromatography with a flame ionization detector (GC-FID). The main experimental parameters, including the extraction and desorption conditions, ionic strength, and fiber bundles, were investigated to improve the extraction efficiency. After optimization, satisfactory linearity (r > 0.99) in the concentration range of 0.02-500 [micro]g/L was obtained, and the enrichment factor of NTD for the five PCBs was between 1150 and 9537 times. The limit of detection (S/N = 3) of five PCBs were measured in ranges of 0.0021-0.01 [micro]g/L. Furthermore, the fiber-packed NTD has excellent durability, and can be reused for 60 cycles. After being stored at room temperature for three days, the storage ability of the NTD had a loss of PCBs less than 10%, and the relative standard deviation (RSD) was less than 10%. When analyzing the PCBs in real water samples, good accuracies (spiked recoveries were in the range of 92.19-98.56%) and precision (the RSD was lower than 12.8%) was obtained., Polychlorinated biphenyls (PCBs) are compounds of the halogenated aromatic group. Owing to excellent chemical and thermal stability, PCBs are widely applied in diverse commercial production. However, the direct discharge of [...]

A method based on gas chromatography--mass spectrometry (GC - MS), coupled with magnetic solid-phase extraction (SPE) with multi-walled carbon-nanotube (MWCNT)-coated iron oxide ([Fe.sub.3][O.sub.4]) as the adsorbent, was developed for analyzing four organophosphate esters in ambient water samples. The magnetic, MWCNT composites were prepared by hydrothermal synthesis and characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, and superconducting quantum interference device magnetometry (SQUID). The extraction and desorption conditions, such as adsorbent dosage, adsorption time, eluent type, and eluent volume, were studied. The adsorbent was used to extract analytes within 50 min. The limit of detection (LOD) was between 0.038-1 [mu]g/L, and the limit of quantitation (LOQ) was between 0.10-3.59 [mu]g/L. The method was applied to analyze organophosphate esters in environmental water samples. A 72.5-89.1% recovery was obtained by analyzing spiked samples with low-, medium-, and high-concentration analytes. The relative standard deviations (RSDs) were less than 10%. This method displayed better sensitivity and accuracy; therefore, it could be successfully used to detect organophosphate esters in environmental water samples., Organophosphate esters (OPEs) are often used as common flame retardants and plasticizers in plastic foam, electronics, furniture, textiles, and construction materials (1,2). It has been reported that the widespread application [...]

As one of the most promising semiconductor oxide materials, titanium dioxide (TiO2) absorbs UV light but not visible light. To address this limitation, the introduction of Ti3+ defects represents a common strategy to render TiO2 visible-light responsive. Unfortunately, current hurdles in Ti3+ generation technologies impeded the widespread application of Ti3+ modified materials. Herein, we demonstrate a simple and mechanistically distinct approach to generating abundant surface-Ti3+ sites without leaving behind oxygen vacancy and sacrificing one-off electron donors. In particular, upon adsorption of organodiboron reagents onto TiO2 nanoparticles, spontaneous electron injection from the diboron-bound O2- site to adjacent Ti4+ site leads to an extremely stable blue surface Ti3+‒O-· complex. Notably, this defect generation protocol is also applicable to other semiconductor oxides including ZnO, SnO2, Nb2O5, and In2O3. Furthermore, the as-prepared photoelectronic device using this strategy affords 103-fold higher visible light response and the fabricated perovskite solar cell shows an enhanced performance.

Porphyrin-based photosensitizers are conventional photodynamic agents that are used clinically. However, their clinical applications have been overshadowed by poor water solubility. In addition, they have weak tumor selectivity, which may cause undesirable side effects. The preparation of novel porphyrin derivatives has been explored for potential applications in photodynamic therapy (PDT). To achieve this goal, lactose-conjugated porphyrin nanoparticles (Lac-Por NPs) have been synthesized and characterized. PDT with Lac-Por NPs exhibited tumor-specific cytotoxicity in lactose receptor-overexpressing HepG2 cells in vitro and in vivo. In summary, we designed and synthesized lactose conjugate porphyrins with enhanced water solubility and tumor selectivity. This work expands the application range of porphyrin-based photosensitizers for cancer treatment. Key words: porphyrin, photodynamic therapy, lactose, anticancer. Les photosensibilisateurs a base de porphyrine sont des agents photodynamiques classiques utilises en clinique. Cependant, leur faible solubilite dans l'eau a nui a leur application en clinique. De plus, leur selectivite tumorale est faible, ce qui peut entrainer des effets secondaires indesirables. Nous avons etudie la preparation de nouveaux derives porphyriques pour une eventuelle application en therapie photodynamique (TPD). Pour ce faire, nous avons synthetise des nanoparticules de porphyrine conjuguee a des molecules de lactose (NP de Lac-Por) et les avons caracterisees. La TPD par les NP de Lac-Por presente une cytotoxicite specifique in vitro et in vivo contre les cellules tumorales HepG2 surexprimant les recepteurs du lactose. En resume, nous avons concu et synthetise des porphyrines conjuguees a des molecules de lactose dont la solubilite dans l'eau et la selectivite tumorale sont accrues. Ces travaux ont permis d'elargir le champ d'application des photosensibilisateurs a base de porphyrine aux fins de traitement du cancer. [Traduit par la Redaction] Mots-cles: porphyrine, therapie photodynamique, lactose, anticancereux., 1. Introduction Photodynamic therapy (PDT) is widely used in cancer treatment. Compared with traditional cancer treatments, it is characterized by a small wound, low toxicity, and high efficiency. (1-3) The [...]

The Ru Kuan kiln is one of the top five famous kilns of the Song Dynasty, and it was reserved for the Imperial Court. The Ru kiln produced an extremely [...]

In this work, activated carbon supported Cu-MOF was used as an acetylene hydrochlorination catalyst to manufacture vinyl chloride. Cu-MOF/AC with 15 wt. % Cu-MOF content has the initial acetylene conversion of 99.2% and vinyl chloride selectivity of 98.5% at 200 [degrees]C. By combining steady-state experiments and physical--chemical characterization results (XPS, BET, [H.sub.2]-TPR, [C.sub.2][H.sub.2]-TPD, XRD, and HCl adsorption experiments), Cu--O--C is shown to slow the reduction of [Cu.sup.2+], improve the reactants adsorption, and strengthen the anti-coking ability of Cu-based catalysts. According to the previous studies and the Eley--Rideal mechanism, it is proposed that [Cu.sup.2+] first adsorbed [C.sub.2][H.sub.2] to generate transition states in acetylene hydrochlorination catalysis. Key words: Cu-MOFs, acetylene hydrochlorination, vinyl chloride. Dans le cadre de ces travaux, nous avons utilise le charbon active (AC) comme support a un reseau metallo-organique a base de cuivre (CuMOF) que nous avons employe comme catalyseur d'hydrochloration de l'acetylene pour la fabrication du chlorure de vinyle. Le CuMOF/AC contenant 15 % p/p de CuMOF convertit 99,2 % de l'acetylene initial pour produire le chlorure de vinyle avec une selectivite de 98,5 % a 200 [degrees]C. En combinant les resultats d'experiences a l'etat d'equilibre et de caracterisation physicochimique (spectroscopie de photoelectrons X [XPS], analyse par la methode Brunauer--Emmet--Teller [BET], reduction thermoprogrammee sous hydrogene [[H.sub.2]RTP], desorption thermoprogrammee d'hydrogene [[H.sub.2]DTP] et experiences d'adsorption de HCl), nous avons montre que la liaison Cu--O--C retarde la reduction du [Cu.sup.2+], ameliore l'adsorption des reactifs et renforce la capacite anti-cokefaction des catalyseurs a base de cuivre. D'apres les etudes precedentes et le mecanisme de Eley--Rideal, nous posons l'hypothese selon laquelle le [Cu.sup.2+] s'adsorberait d'abord sur le [C.sub.2][H.sub.2] pour generer les etats de transition correspondant a la catalyse de l'hydrochloration de l'acetylene. Mots-cles : CuMOF, hydrochloration de l'acetylene, chlorure de vinyle., 1. Introduction Metal--organic frameworks (MOF), as a new class of porous coordination polymer constituted by inorganic building units and an organic linker, have been rapidly developed in many applications, such [...]

Bimetallic porphyrin coordination polymers with various Cu/Cd ratios (Cu-Cd) were synthesized and characterized by X-ray diffraction, infrared spectroscopy, inductively coupled plasma atomic emission spectrometry and transmission electron microscopy. The presence of Cu(II) in the series of bimetallic porphyrin coordination polymers makes them electrochemically active, consequently, they can be used in electrochemical sensing of hydrogen peroxide and sodium nitrite. Their sensing performance was investigated by cyclic voltammetry and chronoamperometry. The performance was affected by Cu/Cd ratio of Cu-Cd, and the optimal Cu-Cd-2 (with Cu/Cd ratio of 1.59) showed the best performance: the detection sensitivities for H.sub.2O.sub.2 and NaNO.sub.2 were 414 and 418 mA/(M cm.sup.2), respectively, and detection limits were 2.7 and 3 [mu]M (S/N = 3). These results demonstrate that Cu-Cd offers great prospect for the construction of non-enzymatic sensors for hydrogen peroxide or sodium nitrite., Author(s): Chunyan Wang [sup.1], Dan Ding [sup.1], Xiaoqing Jiang [sup.1], Bo Zhou [sup.1] Author Affiliations: (1) grid.260474.3, 0000 0001 0089 5711, Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative [...]

Abstract Bright and low‐cost emitting organic molecules are very desirable for electrochemiluminescence (ECL). Here, we report a facile one‐step, three‐component reaction of readily available precursors to synthesize pyrido[1,2‐α]pyrimidine derivatives (1–4), all which give off green photoluminescence (PL). In contrast, the electrochemistry and ECL properties of these luminophores are affected by the extent of the conjugation and the nature of the peripheral substituents. Density functional theory (DFT) calculations identified the aromatic chain substitution could extend the conjugation of pyrido[1,2‐α]pyrimidine core and stabilize the electrogenerated radicals required for generation of an excited state, affording pyrido[1,2‐α]pyrimidine 3 the highest ECL activity among the studied samples. ECL in annihilation route confirmed weak emission, but great improvement was made using oxidizing co‐reactant species (benzoate radical from benzoyl peroxide, BPO) with an efficiency of 43 % relative to that of Ru(bpy)3(PF6)2. The pyrido[1,2‐α]pyrimidine 3/BPO system is more robust than those of reducing co‐reactant species [tri‐n‐propylamine radical or 2‐(dibutylamino) ethanol radical] and is one of the highest among the reported organic electrochemiluminophores. ECL spectroscopy revealed that the monomeric excited states were the main species to emit light. Their straightforward, one‐step, green synthesis, and their structure tunability represent significant advantages in the development of readily accessible dyes for PL and especially ECL applications.

Organotin-based catalysts prepared by a facile and green synthesis route were used in the acetylene hydrochlorination reaction. In detail, organotin-based catalysts were directly synthesized by supporting both organotin and nitrogen compounds on a coal-based columnar activated carbon (AC) using both incipient wetness impregnation and calcination methods. Interestingly, upon addition of nitrogen compounds, the resultant ([SnCl.sub.4] + [C.sub.16][H.sub.34][Cl.sub.2]Sn)/AC catalysts showed higher activity and stability when compared the its ([SnCl.sub.4] + [C.sub.16][H.sub.34][Cl.sub.2]Sn + [C.sub.2][N.sub.4][H.sub.4])/AC counterpart at 200 [degrees]C and a gas hourly space velocity (GHSV, [C.sub.2][H.sub.2] based) of 30 [h.sup.-1]. According to the results, organotin was demonstrated to be the active site, whereas the incorporation of nitrogen allowed partial mitigation of the loss of active components. Key words: organotin-based catalyst, organotin compounds, nitrogen compounds, acetylene hydrochlorination. Nous avons employé des catalyseurs organostanniques préparés par une voie de synthèse simple et écologique pour effectuer la réaction d'hydrochloration de l'acétylène. En particulier, nous avons synthétisé les catalyseurs organostanniques directement par adsorption des composés organostanniques et des composés azotés sur une colonne à base de charbon activé (CA) à l'aide des méthodes d'imprégnation capillaire et de calcination. Fait intéressant, lors de l'incorporation des composés azotés, le catalyseur obtenu ([SnCl.sub.4] + [C.sub.16][H.sub.34][Cl.sub.2]Sn)/CA a présenté une activité et une stabilité plus élevées comparativement à son analogue azoté ([SnCl.sub.4] + [C.sub.16][H.sub.34][Cl.sub.2]Sn + [C.sub.2][N.sub.4][H.sub.4])/CA à 200 [degrees]C, de même qu'une vitesse spatiale horaire de gaz (VSHG, pour le [C.sub.2][H.sub.2]) de 30 [h.sup.-1]. Les résultats ont montré que le composé organnostannique tenait lieu de site actif, tandis que l'incorporation d'azote permettait de réduire en partie la perte des composants actifs. [Traduit par la Rédaction] Mots-clés : catalyseur organostannique, composés organostanniques, composés azotés, hydrochloration d'acétylène., Introduction Polyvinylchloride (PVC) plays a significant role in agriculture, industry, electronic science, and national defense. (1) The industrial production of PVC is typically carried out by direct chlorination of ethylene, [...]