Tony Nguyen, Tyler Hannah, Warren E. Piers, Benjamin Gelfand
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.
我们最近报道了硼氮二氢茚[1,2-b]芴衍生物作为受体在有机光伏器件中的合成和应用。它们所观察到的适度效率可能与它们的还原同系物的性质有关。在这项工作中，我们报告了该家族化合物的两个新成员，它们是通过2,5-二对甲基吡嗪的亲电硼化，然后用ZnAr 2试剂将硼中心进行芳化而制备的。合成了两个衍生物1 (Ar = 2,4,6- f3c6h 2)和2 (Ar = c6f 5)，它们的自由基阴离子1•−和2•−分别由CoCp* 2和CoCp 2化学还原形成。通过结构参数的比较，以及光谱和计算数据的比较，发现自由基阴离子中的未配对电子定位在分子的平面核心，不利于二聚化。然而，与中性起始材料不同的是，1•−和2•−对周围大气具有反应性。这些观察结果表明，减少的化合物是稳定的内在降解途径，但受制于外在的降解装置操作。
{"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}
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.
{"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}
A method for the synthesis of substituted 1,2,4,5-oxadiazaboroles is described, in which hydroxylamines, nitriles, and diarylborinic acids engage in a three-component condensation reaction. The protocol provides access to a substitution pattern that is not readily available through other methods—namely, 2,3-disubstitution, with a tetracoordinate boron center. Structures of representative members of this class of heterocycles were determined by single crystal X-ray diffraction analysis.
{"title":"Synthesis of 1,2,4,5-oxadiazaboroles by three-component condensations of hydroxylamines, nitriles, and diarylborinic acids","authors":"Zhenlu Ge, A. Lough, M. Taylor","doi":"10.1139/cjc-2022-0200","DOIUrl":"https://doi.org/10.1139/cjc-2022-0200","url":null,"abstract":"A method for the synthesis of substituted 1,2,4,5-oxadiazaboroles is described, in which hydroxylamines, nitriles, and diarylborinic acids engage in a three-component condensation reaction. The protocol provides access to a substitution pattern that is not readily available through other methods—namely, 2,3-disubstitution, with a tetracoordinate boron center. Structures of representative members of this class of heterocycles were determined by single crystal X-ray diffraction analysis.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":"17 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87133043","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}
Herein we describe a convenient method for the synthesis of the β-substituted Cys analogs 1a, b and trans-β-mercapto proline 1c, from their corresponding α,β-unsaturated-α-amino esters using p-methoxybenzyl mercaptan as the sulfur source. The intermediate β-thioethers are stable toward chromatographic purification, and after global deprotection the β-mercapto amino acids 1a–c are obtained in good to high yields (64%–99%).
{"title":"Convenient access to β-substituted cysteines and β- and γ-mercapto prolines","authors":"Jacob C. Hansen, Marco Rabuffetti, L. Bunch","doi":"10.1139/cjc-2022-0161","DOIUrl":"https://doi.org/10.1139/cjc-2022-0161","url":null,"abstract":"Herein we describe a convenient method for the synthesis of the β-substituted Cys analogs 1a, b and trans-β-mercapto proline 1c, from their corresponding α,β-unsaturated-α-amino esters using p-methoxybenzyl mercaptan as the sulfur source. The intermediate β-thioethers are stable toward chromatographic purification, and after global deprotection the β-mercapto amino acids 1a–c are obtained in good to high yields (64%–99%).","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":"51 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89579606","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}
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.
{"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}
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.
{"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}
Solid state transformations are important in many areas of science and technology. Herein, a model for predicting the relative energies of stationary points along the reaction pathways for stress-induced solid state transformations is assessed and applied. The model is based on a second-order expansion of the energy of the system with respect to changes in the unit cell, and requires a small number of parameters that can be obtained through quantum chemical calculations. Comparison of the model with the results of quantum chemical calculations indicates that the model accurately reproduces changes in energy occurring during stress-induced transformations over a reasonable range of stresses. A procedure for applying the model to identify stress tensors that are most likely to promote a desired reaction is illustrated. The results also indicate that this procedure provides insight into the connection between the form of a stress tensor and the changes in energy occurring during a stress-induced solid state transformation.
{"title":"Predicting Reaction Barriers in Solid-State Systems Under Stress via Second-Order Energy Expansion","authors":"L. Laverdure, N. Mosey","doi":"10.1139/cjc-2022-0278","DOIUrl":"https://doi.org/10.1139/cjc-2022-0278","url":null,"abstract":"Solid state transformations are important in many areas of science and technology. Herein, a model for predicting the relative energies of stationary points along the reaction pathways for stress-induced solid state transformations is assessed and applied. The model is based on a second-order expansion of the energy of the system with respect to changes in the unit cell, and requires a small number of parameters that can be obtained through quantum chemical calculations. Comparison of the model with the results of quantum chemical calculations indicates that the model accurately reproduces changes in energy occurring during stress-induced transformations over a reasonable range of stresses. A procedure for applying the model to identify stress tensors that are most likely to promote a desired reaction is illustrated. The results also indicate that this procedure provides insight into the connection between the form of a stress tensor and the changes in energy occurring during a stress-induced solid state transformation.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":"84 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81218263","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}
Travis Lundrigan, Joseph P. Tassone, M. Stradiotto
An efficient method for the C–N cross-coupling of (hetero)aryl (pseudo)halides with optically pure α-amino acid esters employing a commercially available nickel catalyst and weak inorganic base was developed. This is the first example of Ni-catalyzed N-arylation of amino acid esters without the use of electrochemistry, which was shown to effectively couple a variety of amino acid tert-butyl esters with (hetero)aryl chlorides, bromides, and tosylates in high yields and excellent enantioretention. Base-mediated racemization was revealed during control experiments, but increasing the steric bulk of the amino acid ester group limited the amount of racemization of the product.
{"title":"Award Lecture Paper: Nickel-Catalyzed N-Arylation of Optically Pure Amino Acid Esters with Activated (Hetero)aryl Electrophiles","authors":"Travis Lundrigan, Joseph P. Tassone, M. Stradiotto","doi":"10.1139/cjc-2022-0290","DOIUrl":"https://doi.org/10.1139/cjc-2022-0290","url":null,"abstract":"An efficient method for the C–N cross-coupling of (hetero)aryl (pseudo)halides with optically pure α-amino acid esters employing a commercially available nickel catalyst and weak inorganic base was developed. This is the first example of Ni-catalyzed N-arylation of amino acid esters without the use of electrochemistry, which was shown to effectively couple a variety of amino acid tert-butyl esters with (hetero)aryl chlorides, bromides, and tosylates in high yields and excellent enantioretention. Base-mediated racemization was revealed during control experiments, but increasing the steric bulk of the amino acid ester group limited the amount of racemization of the product.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":"33 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84187695","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}
{"title":"Note of appreciation","authors":"","doi":"10.1139/cjc-2023-0007","DOIUrl":"https://doi.org/10.1139/cjc-2023-0007","url":null,"abstract":"","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136172696","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}
Ekwevugbe Omugbe, O. Osafile, O. Nenuwe, E. Enaibe, E. E. Elemike
In this paper, we examined the effects of transition metal replacement and ordering in 2D M3C2O2 MXene on the electronic structure, thermal and electrical conductivities using the density functional theory and also the Boltzmann transport theory within the constant relaxation time approximation. We derived the following oxygen functionalized ordered double metal MXenes Ti2YC2O2, Y2TiC2O2 Sc2YC2O2, and Y2ScC2O2 through the surface and sub-layer tuning. The results revealed that the ordered MXenes give rise to different electronic structure and transport properties. The electronic thermal conductivities obtained in terms of the relaxation time increase with increase in absolute temperature, while the electrical conductivities decrease with increase in temperature. The respective transport properties of Y2TiC2O2 and Sc2YC2O2were found to be enhanced due to the increased squared band velocity, density of state and low Seebeck coefficient compared to Ti2YC2O2 and Y2ScC2O2 MXenes. Generally, the MXene materials investigated in this work were found to possess metallic properties with the existence of energy overlap around the Fermi level. The computed formation energies support chemical stability in all the materials.
{"title":"Thermal and electrical transport conductivities of novel ordered double two-dimensional MXenes via density functional theory","authors":"Ekwevugbe Omugbe, O. Osafile, O. Nenuwe, E. Enaibe, E. E. Elemike","doi":"10.1139/cjc-2022-0070","DOIUrl":"https://doi.org/10.1139/cjc-2022-0070","url":null,"abstract":"In this paper, we examined the effects of transition metal replacement and ordering in 2D M3C2O2 MXene on the electronic structure, thermal and electrical conductivities using the density functional theory and also the Boltzmann transport theory within the constant relaxation time approximation. We derived the following oxygen functionalized ordered double metal MXenes Ti2YC2O2, Y2TiC2O2 Sc2YC2O2, and Y2ScC2O2 through the surface and sub-layer tuning. The results revealed that the ordered MXenes give rise to different electronic structure and transport properties. The electronic thermal conductivities obtained in terms of the relaxation time increase with increase in absolute temperature, while the electrical conductivities decrease with increase in temperature. The respective transport properties of Y2TiC2O2 and Sc2YC2O2were found to be enhanced due to the increased squared band velocity, density of state and low Seebeck coefficient compared to Ti2YC2O2 and Y2ScC2O2 MXenes. Generally, the MXene materials investigated in this work were found to possess metallic properties with the existence of energy overlap around the Fermi level. The computed formation energies support chemical stability in all the materials.","PeriodicalId":9420,"journal":{"name":"Canadian Journal of Chemistry","volume":"12 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77805423","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}
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