Canadian Journal of Chemistry最新文献_第8页

Gathering Validity Evidence in the Development of a New Version of the Attitude Toward the Subject of Chemistry Inventory (ASCI-UE) 新版《化学清单》主题态度量表的效度证据收集

IF 1.1 4区化学

Canadian Journal of Chemistry Pub Date : 2023-04-05 DOI: 10.1139/cjc-2022-0162

{"title":"Gathering Validity Evidence in the Development of a New Version of the Attitude Toward the Subject of Chemistry Inventory (ASCI-UE)","authors":"","doi":"10.1139/cjc-2022-0162","DOIUrl":"https://doi.org/10.1139/cjc-2022-0162","url":null,"abstract":"Organic chemistry is one of the most feared and failed courses due to its complex and fast-paced nature. Investigating affective metrics that relate to achievement in these courses can be worthwhile, particularly when these metrics show predictive relationships to achievement. Attitude toward chemistry has been investigated utilizing a variety of instruments. We present herein an instrument related to the well-established ASCIv2. This new instrument was developed utilizing The Standards of Psychological and Educational Measurement which describe five aspects of validity evidence that should be gathered when using instruments in research. Content validity was gathered through consultation with experts. Response process validity was gathered through student interviews. Internal structure validity was collected through confirmatory factor analysis. Relations to other variables were investigated through correlation analysis and structural equation modeling. Consequential validity was studied through measurement invariance testing before comparing scores for subgroups (high- and low-achieving students). Additionally, reliability evidence was tested with Omega coefficients for each of the factors. We showed that all tests and analyses were done with high rigor, and that this new instrument, ASCI-UE, measuring Utility and Emotional Satisfaction, can provide interesting results and implications for research and practice.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":"21 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91139967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Adsorption of tetracycline antibiotics to gold nanoparticles and feasibility of aptamer-based label-free colorimetric detection 四环素类抗生素在金纳米颗粒上的吸附及基于适配体的无标记比色检测的可行性

IF 1.1 4区化学

Canadian Journal of Chemistry Pub Date : 2023-03-10 DOI: 10.1139/cjc-2022-0253

Yuheng Song, Derek H. G. von Eppinghoven, Yang Zhou, Hanxiao Zhang, Juewen Liu

{"title":"Adsorption of tetracycline antibiotics to gold nanoparticles and feasibility of aptamer-based label-free colorimetric detection","authors":"Yuheng Song, Derek H. G. von Eppinghoven, Yang Zhou, Hanxiao Zhang, Juewen Liu","doi":"10.1139/cjc-2022-0253","DOIUrl":"https://doi.org/10.1139/cjc-2022-0253","url":null,"abstract":"Tetracyclines are a group of very important antibiotics that are still in use to date. To extract, detect and remove tetracyclines from the environment, various nanomaterials have been employed. Although gold nanoparticles (AuNPs) are a commonly cited material for these purposes, fundamental understanding of these tetracycline-AuNP systems are still limited. In this work, the adsorption of tetracycline, oxytetracycline and doxycycline to AuNPs was studied. The effect on the colloidal stability of AuNPs, adsorption kinetics, and the resulting adsorption isotherms were measured. While millimolar concentrations of the tetracyclines can cause aggregation of AuNPs, saturated monolayer adsorption was achieved with low micromolar concentrations of the tetracyclines. Adsorption was instantaneous, and adsorption to AuNPs enhanced their intrinsic fluorescence instead of quenching. With the assumption of aptamer/target complexes cannot be easily adsorbed by AuNPs compared to free aptamers, a label-free colorimetric detection method was tested. While the label-free sensor showed target-dependent aggregation of AuNPs, a non-binding mutant aptamer showed the same trend, suggesting that the color change did not reflect aptamer adsorption but other events such as target adsorption. This study indicates the importance of fundamental understanding of target/AuNP interactions to correctly design aptamer and AuNP-based label-free biosensors.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":"67 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83162831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Celebrating the life of Suning Wang 纪念王苏宁的一生

IF 1.1 4区化学

Canadian Journal of Chemistry Pub Date : 2023-03-01 DOI: 10.1139/cjc-2023-0024

Z. Hudson, B. Blight

引用次数: 0

Stable, π-conjugated radical anions of boron–nitrogen dihydroindeno[1,2-b]fluorenes 硼氮二氢茚[1,2-b]芴的稳定π共轭自由基阴离子

4区化学

Canadian Journal of Chemistry Pub Date : 2023-03-01 DOI: 10.1139/cjc-2022-0039

Tony Nguyen, Tyler Hannah, Warren E. Piers, Benjamin Gelfand

{"title":"Stable, π-conjugated radical anions of boron–nitrogen dihydroindeno[1,2-b]fluorenes","authors":"Tony Nguyen, Tyler Hannah, Warren E. Piers, Benjamin Gelfand","doi":"10.1139/cjc-2022-0039","DOIUrl":"https://doi.org/10.1139/cjc-2022-0039","url":null,"abstract":"We have recently reported the synthesis and application of boron–nitrogen dihydroindeno[1,2-b]fluorene derivatives as acceptors in organic photovoltaic devices. Their modest observed efficiencies may be related to the properties of their reduced congeners. In this work, we report two new members of this family of compounds prepared via the electrophilic borylation of 2,5-di- p-tolylpyrazine followed by an arylation of the boron center with ZnAr 2 reagents. Two derivatives, 1 (Ar = 2,4,6-F 3 C 6 H 2 ) and 2 (Ar = C 6 F 5 ) were synthesized, and their radical anions, 1 •− and 2 •− , were formed via chemical reductions with CoCp* 2 and CoCp 2 , respectively. Through comparison of structural parameters, as well as spectroscopic and computational data, the unpaired electron in the radical anions is localized in the planar core of the molecule, and dimerization is disfavored as a result. However, unlike the neutral starting materials, 1 •− and 2 •− are reactive toward ambient atmosphere. These observations suggest that the reduced compounds are stable toward intrinsic degradation pathways but subject to extrinsic degradation in device operation.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135742783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Scan rate and concentration dependence of the voltammograms of substituted phenols on electrodes with different size, diffusion coefficients of phenols in different solvents 取代苯酚在不同尺寸电极上的扫描速率和浓度依赖性，苯酚在不同溶剂中的扩散系数

IF 1.1 4区化学

Canadian Journal of Chemistry Pub Date : 2023-02-24 DOI: 10.1139/cjc-2022-0096

L. Kiss, S. Kunsági-Máté

{"title":"Scan rate and concentration dependence of the voltammograms of substituted phenols on electrodes with different size, diffusion coefficients of phenols in different solvents","authors":"L. Kiss, S. Kunsági-Máté","doi":"10.1139/cjc-2022-0096","DOIUrl":"https://doi.org/10.1139/cjc-2022-0096","url":null,"abstract":"In this work, the effects of the scan rate and the concentration of the substituted phenols on the peak currents or current plateaus have been investigated. Voltammetric curves recorded by a platinum microelectrode varied significantly under different experimental conditions in cases of 4-chlorophenol, 4- tert-butylphenol, and 4-nitrophenol. In the case of 4-methoxyphenol and 4- tert-butylphenol, when the experiments were performed in the lower concentration range in acetonitrile, the plateau current and peak current showed linear dependence on phenol concentration. Therefore, these ranges offer opportunity for further characterization. The electrode reaction of 4-methoxyphenol was found to be a diffusion-controlled process in the solvents applied (water, acetonitrile, dimethyl sulfoxide, dimethyl formamide, nitrobenzene, acetone, dichloromethane, methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol). Diffusion coefficients of 4-methoxyphenol were determined with a microelectrode using the steady-state voltammograms. Diffusion coefficients of other phenols were measured only in acetonitrile with a macroelectrode. In agreement with known theories, the diffusion coefficients showed inversely proportional relationships with the solvent viscosities. Special care was needed in 1-pentanol solvent since the increasing anodic peaks appeared after the first scan and overlaid with the sigmoidal-shaped regular microelectrode voltammograms. This observation is probably due to formation of adhering residual electroactive products.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":"15 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87831001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Synthesis of 1,2,4,5-oxadiazaboroles by three-component condensations of hydroxylamines, nitriles, and diarylborinic acids 羟胺、腈和二酰基硼酸三组分缩合合成1,2,4,5-恶二唑硼醚

IF 1.1 4区化学

Canadian Journal of Chemistry Pub Date : 2023-02-23 DOI: 10.1139/cjc-2022-0200

Zhenlu Ge, A. Lough, M. Taylor

引用次数: 0

Convenient access to β-substituted cysteines and β- and γ-mercapto prolines 方便地获得β-取代半胱氨酸和β-和γ-巯基脯氨酸

IF 1.1 4区化学

Canadian Journal of Chemistry Pub Date : 2023-02-15 DOI: 10.1139/cjc-2022-0161

Jacob C. Hansen, Marco Rabuffetti, L. Bunch

引用次数: 0

Dicarbon defect in hexagonal boron nitride monolayer - a theoretical study 六方氮化硼单层碳缺陷的理论研究

IF 1.1 4区化学

Canadian Journal of Chemistry Pub Date : 2023-02-15 DOI: 10.1139/cjc-2022-0291

T. Korona, J. Jankowska, Emran Masoumifeshani

{"title":"Dicarbon defect in hexagonal boron nitride monolayer - a theoretical study","authors":"T. Korona, J. Jankowska, Emran Masoumifeshani","doi":"10.1139/cjc-2022-0291","DOIUrl":"https://doi.org/10.1139/cjc-2022-0291","url":null,"abstract":"A comprehensive theoretical study of the lowest electronic vertical excitations of the CBCN defect in the monolayer of hexagonal boron nitride has been performed. Both the periodic boundary conditions approach and the finite-cluster simulation of the defect have been utilized at the density-functional theory (DFT) level. Clusters of increasing sizes have been used in order to estimate artefacts resulting from edge effects. The stability of the results with respect to several density functionals and various basis sets has been also examined. High-level ab initio calculations with methods like EOM-CCSD, ADC(2), and TD-CC2, were performed for the smallest clusters. It turns out that TD-DFT with the CAM-B3LYP functional gives similar lowest excitation energies as EOM-CCSD, ADC(2), and TD-CC2. The lowest excitation energies resulting from the periodic-boundary calculation utilizing the Bethe-Salpeter equation are in agreement with the results for finite clusters. The analysis of important configurations and transition densities shows that for all studied methods, the lowest excited state is localized on two carbon atoms and their closest neighbours and has a large dipole transition moment. The optimized geometries for the lowest two excited states indicate that in both cases the carbon-carbon bond becomes a single bond, while for the second excited state additionally one from boron-nitrogen bonds looses its partially double character. The calculation of the excitation energies at the respective optimal geometry reveals that these two energies become about 0.5 eV lower than vertical excitations from the ground-state geometry.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":"47 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82201004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Do we need delocalised wavefunctions for the excited state dynamics of 1,1-diﬂuoroethylene? 1,1-二氟乙烯的激发态动力学需要离域波函数吗?

IF 1.1 4区化学

Canadian Journal of Chemistry Pub Date : 2023-02-14 DOI: 10.1139/cjc-2022-0267

Sandra G'omez, N. Singer, L. Gonz'alez, G. Worth

{"title":"Do we need delocalised wavefunctions for the excited state dynamics of 1,1-diﬂuoroethylene?","authors":"Sandra G'omez, N. Singer, L. Gonz'alez, G. Worth","doi":"10.1139/cjc-2022-0267","DOIUrl":"https://doi.org/10.1139/cjc-2022-0267","url":null,"abstract":"In this work we set up a model Hamiltonian to study the excited state quantum dynamics of 1,1-difluoroethylene, a molecule that has equivalent atoms exchanged by a torsional symmetry operation leading to equivalent minima on the potential energy surface. In systems with many degrees of freedom where the minimum energy geometry is not unique, the ground state wavefunction will be delocalised among multiple minima. In this small test system, we probe the excited state dynamics considering localised (in a single minimum) and delocalised (spread over among multiple minima) wavefunctions and check whether this choice would influence the final outcome of the quantum dynamics calculations. Our molecular Hamiltonian comprises seven electronic states, including valence and Rydberg states, computed with the MS-CASPT2 method and projected onto the vibrational coordinates of the twelve normal modes of 1,1-difluoroethylene in its vibrational ground state. This Hamiltonian has been symmetrised along the torsional degree of freedom to make both minima completely equivalent and the model is supported by the excellent agreement with the experimental absorption spectrum. Quantum dynamics results show that the different initial conditions studied do not appreciably affect the excited state populations or the absorption spectrum when the dynamics is simulated assuming a delta pulse excitation. Future work will look at whether initial superpositions can be formed that guide the system, e.g. to a single minimum.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":"18 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84570707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Predicting Reaction Barriers in Solid-State Systems Under Stress via Second-Order Energy Expansion 利用二阶能量膨胀预测应力下固体体系的反应势垒

IF 1.1 4区化学

Canadian Journal of Chemistry Pub Date : 2023-02-14 DOI: 10.1139/cjc-2022-0278

L. Laverdure, N. Mosey

引用次数: 0