Konrad Burkmann, Franziska Habermann, Roman Gumeniuk, Florian Mertens
The heat capacity of yttrium(III) bromide (YBr3) in the temperature range from 2 K to 300 K has been determined using a Physical Property Measurement System (PPMS). From these data the absolute entropy of the compound at 298.15 K has been derived.
利用物理性质测量系统（PPMS）测定了溴化钇（III）（YBr3）在 2 K 至 300 K 温度范围内的热容量。根据这些数据得出了该化合物在 298.15 K 时的绝对熵。
{"title":"Low-temperature heat capacity and absolute entropy of yttrium(III) bromide (YBr3)","authors":"Konrad Burkmann, Franziska Habermann, Roman Gumeniuk, Florian Mertens","doi":"10.1515/znb-2024-0010","DOIUrl":"https://doi.org/10.1515/znb-2024-0010","url":null,"abstract":"The heat capacity of yttrium(III) bromide (YBr<jats:sub>3</jats:sub>) in the temperature range from 2 K to 300 K has been determined using a Physical Property Measurement System (PPMS). From these data the absolute entropy of the compound at 298.15 K has been derived.","PeriodicalId":23831,"journal":{"name":"Zeitschrift für Naturforschung B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140609790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tobias A. Teichtmeister, Alexander Hugo Bernhart, Klaus Wurst, Hubert Huppertz
This report presents work on the orthorhombic phases Ln2CdB5O11(OH) (Ln = Tm, Lu). The title compounds were synthesized in a Walker-type multianvil device at 7 GPa and 650 °C, and the resulting samples were thoroughly investigated through single-crystal and powder X-ray diffraction methods. Lu2CdB5O11(OH) crystallizes in the space group Pmna (no. 53) with the unit cell parameters a = 12.772(2), b = 4.6017(7), and c = 12.481(2) Å. Similar unit cell parameters are observed for the isotypic Tm analogue compound. The crystals have a layered crystal structure built up by four-, five-, and eight-membered rings of corner-sharing [BO4] tetrahedra. The structural data are accompanied by attenuated total reflection (ATR) infrared spectra and energy-dispersive X-ray spectroscopy (EDX).
本报告介绍了有关正交相 Ln 2CdB5O11(OH) （Ln = Tm、Lu）的研究工作。标题化合物是在 7 GPa 和 650 °C条件下通过沃克型多坩埚装置合成的，所得样品通过单晶和粉末 X 射线衍射方法进行了深入研究。Lu2CdB5O11(OH)在空间群 Pmna（编号 53）中结晶，单胞参数为 a = 12.772(2)、b = 4.6017(7)和 c = 12.481(2)埃。晶体具有由四元、五元和八元环组成的分角[BO4]四面体层状晶体结构。结构数据附有衰减全反射（ATR）红外光谱和能量色散 X 射线光谱（EDX）。
{"title":"High-pressure/high-temperature synthesis of Ln 2CdB5O11(OH) (Ln = Tm, Lu)","authors":"Tobias A. Teichtmeister, Alexander Hugo Bernhart, Klaus Wurst, Hubert Huppertz","doi":"10.1515/znb-2024-0011","DOIUrl":"https://doi.org/10.1515/znb-2024-0011","url":null,"abstract":"This report presents work on the orthorhombic phases <jats:italic>Ln</jats:italic> <jats:sub>2</jats:sub>CdB<jats:sub>5</jats:sub>O<jats:sub>11</jats:sub>(OH) (<jats:italic>Ln</jats:italic> = Tm, Lu). The title compounds were synthesized in a Walker-type multianvil device at 7 GPa and 650 °C, and the resulting samples were thoroughly investigated through single-crystal and powder X-ray diffraction methods. Lu<jats:sub>2</jats:sub>CdB<jats:sub>5</jats:sub>O<jats:sub>11</jats:sub>(OH) crystallizes in the space group <jats:italic>Pmna</jats:italic> (no. 53) with the unit cell parameters <jats:italic>a</jats:italic> = 12.772(2), <jats:italic>b</jats:italic> = 4.6017(7), and <jats:italic>c</jats:italic> = 12.481(2) Å. Similar unit cell parameters are observed for the isotypic Tm analogue compound. The crystals have a layered crystal structure built up by four-, five-, and eight-membered rings of corner-sharing [BO<jats:sub>4</jats:sub>] tetrahedra. The structural data are accompanied by attenuated total reflection (ATR) infrared spectra and energy-dispersive X-ray spectroscopy (EDX).","PeriodicalId":23831,"journal":{"name":"Zeitschrift für Naturforschung B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140574219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maren Rasmussen, Christian Näther, Wolfgang Bensch
A new arsenato-polyoxovanadate with the composition {[Ni(dien)2]3[V6As8O26]}2+·2 Cl– has been crystallized under solvothermal conditions as turquoise block-like crystals. The central structural feature is the [V6IVAs8IIIO26]4– cluster anion, which is composed of two trinuclear {V3O11} groups consisting of three edge-sharing VO5 polyhedra. Pairs of pyramidal AsO3 moieties share a common corner forming As2O5 units, which interconnect the {V3O11} groups. One of the [Ni(dien)2]2+ complexes adopts the s-fac (Ni1) and the second complex the mer configuration (Ni2). The Cl− anion is involved in strong hydrogen bonding interactions and links the [Ni(dien)2]2+ complexes to form twelve-membered rings which host the [V6As8O26]4– cluster anions. The Hirshfeld surface analysis yields a detailed picture of the intermolecular interactions revealing clear differences for the two unique [Ni(dien)2]2+ complexes. Intermolecular contacts also include As⋯H, O⋯H and H⋯H interactions. In the electronic spectrum the bands of d–d transitions of the vanadyl group and of the Ni2+ cations overlap, preventing a detailed analysis.
{"title":"Solvothermal synthesis and selected properties of {[Ni(dien)2]3[V6As8O26]}2+·2 Cl– featuring the small [V6 IVAs8 IIIO26]4– cluster anion","authors":"Maren Rasmussen, Christian Näther, Wolfgang Bensch","doi":"10.1515/znb-2023-0074","DOIUrl":"https://doi.org/10.1515/znb-2023-0074","url":null,"abstract":"A new arsenato-polyoxovanadate with the composition {[Ni(dien)<jats:sub>2</jats:sub>]<jats:sub>3</jats:sub>[V<jats:sub>6</jats:sub>As<jats:sub>8</jats:sub>O<jats:sub>26</jats:sub>]}<jats:sup>2+</jats:sup>·2 Cl<jats:sup>–</jats:sup> has been crystallized under solvothermal conditions as turquoise block-like crystals. The central structural feature is the [V<jats:sub>6</jats:sub> <jats:sup>IV</jats:sup>As<jats:sub>8</jats:sub> <jats:sup>III</jats:sup>O<jats:sub>26</jats:sub>]<jats:sup>4–</jats:sup> cluster anion, which is composed of two trinuclear {V<jats:sub>3</jats:sub>O<jats:sub>11</jats:sub>} groups consisting of three edge-sharing VO<jats:sub>5</jats:sub> polyhedra. Pairs of pyramidal AsO<jats:sub>3</jats:sub> moieties share a common corner forming As<jats:sub>2</jats:sub>O<jats:sub>5</jats:sub> units, which interconnect the {V<jats:sub>3</jats:sub>O<jats:sub>11</jats:sub>} groups. One of the [Ni(dien)<jats:sub>2</jats:sub>]<jats:sup>2+</jats:sup> complexes adopts the <jats:italic>s-fac</jats:italic> (Ni1) and the second complex the <jats:italic>mer</jats:italic> configuration (Ni2). The Cl<jats:sup>−</jats:sup> anion is involved in strong hydrogen bonding interactions and links the [Ni(dien)<jats:sub>2</jats:sub>]<jats:sup>2+</jats:sup> complexes to form twelve-membered rings which host the [V<jats:sub>6</jats:sub>As<jats:sub>8</jats:sub>O<jats:sub>26</jats:sub>]<jats:sup>4–</jats:sup> cluster anions. The Hirshfeld surface analysis yields a detailed picture of the intermolecular interactions revealing clear differences for the two unique [Ni(dien)<jats:sub>2</jats:sub>]<jats:sup>2+</jats:sup> complexes. Intermolecular contacts also include As⋯H, O⋯H and H⋯H interactions. In the electronic spectrum the bands of <jats:italic>d</jats:italic>–<jats:italic>d</jats:italic> transitions of the vanadyl group and of the Ni<jats:sup>2+</jats:sup> cations overlap, preventing a detailed analysis.","PeriodicalId":23831,"journal":{"name":"Zeitschrift für Naturforschung B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140573878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Olaf Reckeweg, Francis J. DiSalvo, Robert E. Dinnebier, Christian Funk, Thomas Schleid
Cesium dicyanamide Cs[C2N3] (≡ Cs[N(CN)2] or Cs[dca]) was obtained by a metathesis reaction in form of transparent colorless platelets. The results of single-crystal X-ray structure measurements and refinements (C2/c, Z = 8) with the monoclinic cell parameters a = 932.31(8), b = 1274.67(9), c = 824.94(7) pm, β = 110.803(3)° at −70 °C and a = 939.59(7), b = 1281.58(8), c = 827.57(6) pm, β = 110.610(3)° at 20 °C corroborate earlier results for this compound. The Raman and IR spectra of Cs[C2N3] are presented for the first time and the result compares well with those of NaCs2[C2N3]3. The heat-driven cyclotrimerization process of Cs[C2N3] was studied by thermal analyses (DSC) and temperature-dependent X-ray powder diffraction methods. At 370 °C, its trimerization product Cs3[C6N9] is formed, crystallizing in the orthorhombic space group Pbam with the cell parameters a = 3043.0(3), b = 1052.4(1) and c = 415.21(4) pm for Z = 4. The IR spectrum of this cesium tricyanomelaminate (Cs3[C6N9] or Cs3[TCM]) is presented, but a well-resolved Raman spectrum could not be acquired owing to fluorescence phenomena. An overview about the cyclotrimerization reactions of all pseudo-binary alkali-metal dicyanamides (A[C2N3]) to their corresponding tricyanomelaminates (A3[C6N9]) with A = Li–Cs gives a basis for a discussion of the different thermal and structural characteristics.
通过偏合成反应获得了无色透明小板形式的双氰胺铯 Cs[C2N3]（≡ Cs[N(CN)2]或 Cs[dca]）。单晶 X 射线结构测量和细化（C2/c，Z = 8）结果显示，单斜晶胞参数 a = 932.31(8)，b = 1274.67(9)，c = 824.94(7)pm，β = 110.803(3)°，以及 a = 939.59(7)，b = 1281.58(8)，c = 827.57(6)pm，β = 110.610(3)°，温度为 20 °C。首次展示了 Cs[C2N3] 的拉曼光谱和红外光谱，其结果与 NaCs2[C2N3]3 的结果相差无几。热分析（DSC）和随温度变化的 X 射线粉末衍射方法研究了 Cs[C2N3] 的热驱动环三聚过程。在 370 °C 时，形成了其三聚产物 Cs3[C6N9]，在正交空间群 Pbam 中结晶，晶胞参数为 a = 3043.0(3)，b = 1052.4(1)，c = 415.21(4) pm，Z = 4。本文展示了这种铯三氰基氨基甲酸盐（Cs3[C6N9] 或 Cs3[TCM]）的红外光谱，但由于荧光现象，无法获得分辨率较高的拉曼光谱。概述了所有假二元碱金属二氰胺（A[C2N3]）到其相应的三氰胺层析物（A 3[C6N9]）（A = 锂-硒）的环化反应，为讨论不同的热和结构特征提供了基础。
{"title":"From Cs[C2N3] to Cs3[C6N9] – a thermal and structural investigation","authors":"Olaf Reckeweg, Francis J. DiSalvo, Robert E. Dinnebier, Christian Funk, Thomas Schleid","doi":"10.1515/znb-2023-0101","DOIUrl":"https://doi.org/10.1515/znb-2023-0101","url":null,"abstract":"Cesium dicyanamide Cs[C<jats:sub>2</jats:sub>N<jats:sub>3</jats:sub>] (≡ Cs[N(CN)<jats:sub>2</jats:sub>] or Cs[dca]) was obtained by a metathesis reaction in form of transparent colorless platelets. The results of single-crystal X-ray structure measurements and refinements (<jats:italic>C</jats:italic>2/<jats:italic>c</jats:italic>, <jats:italic>Z</jats:italic> = 8) with the monoclinic cell parameters <jats:italic>a</jats:italic> = 932.31(8), <jats:italic>b</jats:italic> = 1274.67(9), <jats:italic>c</jats:italic> = 824.94(7) pm, <jats:italic>β</jats:italic> = 110.803(3)° at −70 °C and <jats:italic>a</jats:italic> = 939.59(7), <jats:italic>b</jats:italic> = 1281.58(8), <jats:italic>c</jats:italic> = 827.57(6) pm, <jats:italic>β</jats:italic> = 110.610(3)° at 20 °C corroborate earlier results for this compound. The Raman and IR spectra of Cs[C<jats:sub>2</jats:sub>N<jats:sub>3</jats:sub>] are presented for the first time and the result compares well with those of NaCs<jats:sub>2</jats:sub>[C<jats:sub>2</jats:sub>N<jats:sub>3</jats:sub>]<jats:sub>3</jats:sub>. The heat-driven cyclotrimerization process of Cs[C<jats:sub>2</jats:sub>N<jats:sub>3</jats:sub>] was studied by thermal analyses (DSC) and temperature-dependent X-ray powder diffraction methods. At 370 °C, its trimerization product Cs<jats:sub>3</jats:sub>[C<jats:sub>6</jats:sub>N<jats:sub>9</jats:sub>] is formed, crystallizing in the orthorhombic space group <jats:italic>Pbam</jats:italic> with the cell parameters <jats:italic>a</jats:italic> = 3043.0(3), <jats:italic>b</jats:italic> = 1052.4(1) and <jats:italic>c</jats:italic> = 415.21(4) pm for <jats:italic>Z</jats:italic> = 4. The IR spectrum of this cesium tricyanomelaminate (Cs<jats:sub>3</jats:sub>[C<jats:sub>6</jats:sub>N<jats:sub>9</jats:sub>] or Cs<jats:sub>3</jats:sub>[TCM]) is presented, but a well-resolved Raman spectrum could not be acquired owing to fluorescence phenomena. An overview about the cyclotrimerization reactions of all pseudo-binary alkali-metal dicyanamides (<jats:italic>A</jats:italic>[C<jats:sub>2</jats:sub>N<jats:sub>3</jats:sub>]) to their corresponding tricyanomelaminates (<jats:italic>A</jats:italic> <jats:sub>3</jats:sub>[C<jats:sub>6</jats:sub>N<jats:sub>9</jats:sub>]) with <jats:italic>A</jats:italic> = Li–Cs gives a basis for a discussion of the different thermal and structural characteristics.","PeriodicalId":23831,"journal":{"name":"Zeitschrift für Naturforschung B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140574048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tobias Wittemann, Halil İbrahim Sözen, Mehtap Oezaslan, Thorsten Klüner
Understanding the chemisorption of atoms on precious metal surfaces is of substantial interest for the rational design of heterogeneous and electrochemical catalysts. In this study, we report density functional theory (DFT) investigations of the chemisorption of atomic H and O on bimetallic PtxIry(111) surfaces for bifunctional anode catalyst materials in polymer electrolyte membrane (PEM) fuel cells. We found that for both adsorbates, the adsorption on the Pt(111) surface is in general less exothermic than on the Ir(111) surface. Our study has revealed that chemisorption on the bimetallic surfaces becomes more stable with increasing number of Ir surface atoms at the adsorption site. While for hydrogen atoms the ONTOP sites yield the most negative adsorption energies, the chemisorption of oxygen atoms appears to be most stable on the FCC sites for both the mono- and bimetallic surfaces. Using the ab initio thermodynamics approach, we calculated phase diagrams for the chemisorption of H and O atoms on these metal surfaces in order to transfer our findings to finite temperature and pressure conditions. Our theoretical results may provide an improved understanding of the hydrogen oxidation reaction (HOR) and oxygen evolution reaction (OER) on intermetallic PtxIry(111) surfaces and may be helpful for the rational design of new bifunctional PEM fuel cell anode catalyst materials.
了解贵金属表面原子的化学吸附对合理设计异相催化剂和电化学催化剂具有重要意义。在本研究中，我们报告了密度泛函理论（DFT）对 H 原子和 O 原子在双金属 Pt x Ir y (111) 表面上的化学吸附的研究，这些催化剂可用于聚合物电解质膜燃料电池（PEM）中的双功能阳极催化剂材料。我们发现，对于这两种吸附剂，铂（111）表面的吸附放热一般低于铱（111）表面。我们的研究表明，随着吸附位点上 Ir 表面原子数的增加，双金属表面上的化学吸附变得更加稳定。对于氢原子来说，ONTOP 位点产生的吸附能是最负的，而对于单金属和双金属表面来说，氧原子在 FCC 位点的化学吸附似乎是最稳定的。利用 ab initio 热力学方法，我们计算了这些金属表面上 H 原子和 O 原子化学吸附的相图，以便将我们的发现转移到有限温度和压力条件下。我们的理论结果可加深对金属间铂 x 铱 y (111) 表面氢氧化反应和氧进化反应的理解，并有助于合理设计新型双功能 PEM 燃料电池阳极催化剂材料。
{"title":"Ab initio calculations of the chemisorption of atomic H and O on Pt and Ir metal and on bimetallic Pt x Ir y surfaces","authors":"Tobias Wittemann, Halil İbrahim Sözen, Mehtap Oezaslan, Thorsten Klüner","doi":"10.1515/znb-2023-0087","DOIUrl":"https://doi.org/10.1515/znb-2023-0087","url":null,"abstract":"Understanding the chemisorption of atoms on precious metal surfaces is of substantial interest for the rational design of heterogeneous and electrochemical catalysts. In this study, we report density functional theory (DFT) investigations of the chemisorption of atomic H and O on bimetallic Pt<jats:sub> <jats:italic>x</jats:italic> </jats:sub>Ir<jats:sub> <jats:italic>y</jats:italic> </jats:sub>(111) surfaces for bifunctional anode catalyst materials in polymer electrolyte membrane (PEM) fuel cells. We found that for both adsorbates, the adsorption on the Pt(111) surface is in general less exothermic than on the Ir(111) surface. Our study has revealed that chemisorption on the bimetallic surfaces becomes more stable with increasing number of Ir surface atoms at the adsorption site. While for hydrogen atoms the ONTOP sites yield the most negative adsorption energies, the chemisorption of oxygen atoms appears to be most stable on the FCC sites for both the mono- and bimetallic surfaces. Using the <jats:italic>ab initio</jats:italic> thermodynamics approach, we calculated phase diagrams for the chemisorption of H and O atoms on these metal surfaces in order to transfer our findings to finite temperature and pressure conditions. Our theoretical results may provide an improved understanding of the hydrogen oxidation reaction (HOR) and oxygen evolution reaction (OER) on intermetallic Pt<jats:sub> <jats:italic>x</jats:italic> </jats:sub>Ir<jats:sub> <jats:italic>y</jats:italic> </jats:sub>(111) surfaces and may be helpful for the rational design of new bifunctional PEM fuel cell anode catalyst materials.","PeriodicalId":23831,"journal":{"name":"Zeitschrift für Naturforschung B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140573859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marlena Volck, Bernhard Gadermaier, Volker Hennige, H. Martin R. Wilkening, Ilie Hanzu
The hexagonal high-temperature form of LiBH4 is known as a fast ion conductor. Here, we investigated its suitability as a solid electrolyte in high-temperature all-solid-state cells when combined with the following active materials: Li metal, graphite, lithium titanium oxide (Li4Ti5O12, LTO), and nanocrystalline rutile (TiO2). First results using lithium anodes and rutile nanorods as cathode material show that a cell constructed by simple cold-pressing operates at reversible discharge capacities in the order of 125 mA h g−1 at a C-rate of C/5 and at temperatures as high as 393 K. Besides TiO2, the compatibility of the LiBH4 with other active materials such as graphite and LTO was tested. We found evidence of possible interface instabilities that manifest through rare, yet still detrimental, self-charge processes that may be relevant for hydrogen storage applications. Moreover, we investigated the long-term cycling behavior of the cells assembled and demonstrate the successful employment of LiBH4 as an easily processable model solid electrolyte in practical test cells.
六方高温型 LiBH4 是众所周知的快速离子导体。在此，我们研究了它与以下活性材料结合后作为高温全固态电池固体电解质的适用性：锂金属、石墨、锂钛氧化物（Li4Ti5O12，LTO）和纳米晶金红石（TiO2）。使用锂阳极和金红石纳米棒作为阴极材料的首批研究结果表明，通过简单的冷压工艺制成的电池在 C/5 的 C 速率和高达 393 K 的温度条件下可达到 125 mA h g-1 的可逆放电容量。我们发现了界面不稳定性的证据，这种不稳定性通过罕见但仍有害的自充电过程表现出来，可能与储氢应用有关。此外，我们还研究了所组装电池的长期循环行为，并证明了 LiBH4 作为一种易于加工的模型固体电解质在实际测试电池中的成功应用。
{"title":"High-temperature all-solid-state batteries with LiBH4 as electrolyte – a case study exploring the performance of TiO2 nanorods, Li4Ti5O12 and graphite as active materials","authors":"Marlena Volck, Bernhard Gadermaier, Volker Hennige, H. Martin R. Wilkening, Ilie Hanzu","doi":"10.1515/znb-2023-0093","DOIUrl":"https://doi.org/10.1515/znb-2023-0093","url":null,"abstract":"The hexagonal high-temperature form of LiBH<jats:sub>4</jats:sub> is known as a fast ion conductor. Here, we investigated its suitability as a solid electrolyte in high-temperature all-solid-state cells when combined with the following active materials: Li metal, graphite, lithium titanium oxide (Li<jats:sub>4</jats:sub>Ti<jats:sub>5</jats:sub>O<jats:sub>12</jats:sub>, LTO), and nanocrystalline rutile (TiO<jats:sub>2</jats:sub>). First results using lithium anodes and rutile nanorods as cathode material show that a cell constructed by simple cold-pressing operates at reversible discharge capacities in the order of 125 mA h g<jats:sup>−1</jats:sup> at a <jats:italic>C</jats:italic>-rate of <jats:italic>C</jats:italic>/5 and at temperatures as high as 393 K. Besides TiO<jats:sub>2</jats:sub>, the compatibility of the LiBH<jats:sub>4</jats:sub> with other active materials such as graphite and LTO was tested. We found evidence of possible interface instabilities that manifest through rare, yet still detrimental, self-charge processes that may be relevant for hydrogen storage applications. Moreover, we investigated the long-term cycling behavior of the cells assembled and demonstrate the successful employment of LiBH<jats:sub>4</jats:sub> as an easily processable model solid electrolyte in practical test cells.","PeriodicalId":23831,"journal":{"name":"Zeitschrift für Naturforschung B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140574074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Very recently, N-heterocyclic carbenes (NHCs) have found a wide range of applications in the fields of catalysis and nonlinear optics. Herein, we have employed 1,3-bis-(1(S)-benzyl)-4,5-dihydro-imidazol-based carbene as a reference molecule and substituted one H atom from each CH2 of the benzyl groups in both sides by CH3, NH2, and CF3 to study the thermodynamic and opto-electronic properties of NHCs theoretically. It was observed that the enthalpy (H), Gibb’s free energy (G), specific heat capacity (Cv), and entropy (S) increase significantly in the presence of the electron-withdrawing groups compared to the electron-donating groups. The IR active in-plane bending vibrations of the CH (NHC) group are shifted to the higher frequency region for the considered substituted molecules compared to the reference carbene. The analysis of the electronic properties shows that the CH3-substituted carbene is more reactive for catalytic activities compared to other NHCs. The calculated nonlinear optical (NLO) properties reveal that the NH2-substituted NHC has the largest hyperpolarizability value whereas the CH3-substituted NHC has the largest dipole moment and polarizability among all, making them potential candidates for the development of NLO materials.
{"title":"A computational characterization of N-heterocyclic carbenes for catalytic and nonlinear optical applications","authors":"Mohammad Alauddin, Mazharul M. Islam","doi":"10.1515/znb-2023-0092","DOIUrl":"https://doi.org/10.1515/znb-2023-0092","url":null,"abstract":"Very recently, N-heterocyclic carbenes (NHCs) have found a wide range of applications in the fields of catalysis and nonlinear optics. Herein, we have employed 1,3-bis-(1(<jats:italic>S</jats:italic>)-benzyl)-4,5-dihydro-imidazol-based carbene as a reference molecule and substituted one H atom from each CH<jats:sub>2</jats:sub> of the benzyl groups in both sides by CH<jats:sub>3</jats:sub>, NH<jats:sub>2</jats:sub>, and CF<jats:sub>3</jats:sub> to study the thermodynamic and opto-electronic properties of NHCs theoretically. It was observed that the enthalpy (<jats:italic>H</jats:italic>), Gibb’s free energy (<jats:italic>G</jats:italic>), specific heat capacity (<jats:italic>C</jats:italic> <jats:sub>v</jats:sub>), and entropy (<jats:italic>S</jats:italic>) increase significantly in the presence of the electron-withdrawing groups compared to the electron-donating groups. The IR active in-plane bending vibrations of the CH (NHC) group are shifted to the higher frequency region for the considered substituted molecules compared to the reference carbene. The analysis of the electronic properties shows that the CH<jats:sub>3</jats:sub>-substituted carbene is more reactive for catalytic activities compared to other NHCs. The calculated nonlinear optical (NLO) properties reveal that the NH<jats:sub>2</jats:sub>-substituted NHC has the largest hyperpolarizability value whereas the CH<jats:sub>3</jats:sub>-substituted NHC has the largest dipole moment and polarizability among all, making them potential candidates for the development of NLO materials.","PeriodicalId":23831,"journal":{"name":"Zeitschrift für Naturforschung B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140573860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The optical band gap of the semiconductor CuTa2O6, synthesised via solid-state reaction, can be greatly reduced by annealing in ammonia, which leads to a significant red-shift of the visible light absorption. Using X-ray photoelectron spectroscopy (XPS), we have shown that this absorption extension does not result from the incorporation of nitrogen, but can be attributed to copper defects formed under the reducing conditions of ammonia treatment. Photocatalytic hydrogen evolution experiments were used to investigate the influence of these defects on the photocatalytic performance. We have further shown that CuTa2O6 with similar increased visible light absorption can be prepared by annealing with an organic reducing agent – sodium citrate – in inert gas atmosphere.
通过固态反应合成的半导体 CuTa2O6 在氨气中退火后，其光带隙会大大减小，从而导致可见光吸收的显著红移。利用 X 射线光电子能谱（XPS），我们证明了这种吸收扩展不是由于氮的加入，而是由于在氨处理的还原条件下形成的铜缺陷。我们利用光催化氢进化实验研究了这些缺陷对光催化性能的影响。我们还进一步证明，在惰性气体环境中使用有机还原剂柠檬酸钠退火，可以制备出具有类似的可见光吸收率增加的 CuTa2O6。
{"title":"Origin of extended visible light absorption in nitrogen-doped CuTa2O6 perovskites: the role of copper defects","authors":"Morten Weiss, Anja Hofmann, Roland Marschall","doi":"10.1515/znb-2023-0094","DOIUrl":"https://doi.org/10.1515/znb-2023-0094","url":null,"abstract":"The optical band gap of the semiconductor CuTa<jats:sub>2</jats:sub>O<jats:sub>6</jats:sub>, synthesised <jats:italic>via</jats:italic> solid-state reaction, can be greatly reduced by annealing in ammonia, which leads to a significant red-shift of the visible light absorption. Using X-ray photoelectron spectroscopy (XPS), we have shown that this absorption extension does not result from the incorporation of nitrogen, but can be attributed to copper defects formed under the reducing conditions of ammonia treatment. Photocatalytic hydrogen evolution experiments were used to investigate the influence of these defects on the photocatalytic performance. We have further shown that CuTa<jats:sub>2</jats:sub>O<jats:sub>6</jats:sub> with similar increased visible light absorption can be prepared by annealing with an organic reducing agent – sodium citrate – in inert gas atmosphere.","PeriodicalId":23831,"journal":{"name":"Zeitschrift für Naturforschung B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140574044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bader A. Salameh, Eman H. Al-Hushki, Wamidh H. Talib, Raed Ghanem, Fatima-Azzahra Delmani, Asma I. Mahmod
A series of 3-chloro-1-aryl-4-dihydro-2H-pyrrolo[2,3-b]quinoxalin-2-ones and 3-chloro-1-aryl-6,7-dimethyl-1,4-dihydro-2H-pyrrolo[2,3-b]quinoxalin-2-ones was prepared by the condensation of o-phenylenediamine or 4,5-dimethyl-1,2-aminobenzene with N-aryl-3,4-dichloro-maleimides. All the prepared quinoxalines were tested for their antitumor activity against three human cancer cell lines (prostate cells PC3, colorectal cells Caco-2, and cervical cells HeLa), and a mammalian cell line (Vero cells). The compounds were also tested for their antibacterial properties against three different bacterial cells Escherichia coli, Bacillus spizizenii, and Pseudomonas aeruginosa. The compounds 3c, 3d, 3g, 3h, 3i and 4a, 4b, 4h showed anti-proliferative activity against the tested cell lines. Regarding their antibacterial activity, compounds 3a, 3g, 4a, and 4h showed inhibitory activity against E. coli, and B. spizizenii only.
{"title":"A new class of pyrrolo[2,3-b]quinoxalines: synthesis, anticancer and antimicrobial activities","authors":"Bader A. Salameh, Eman H. Al-Hushki, Wamidh H. Talib, Raed Ghanem, Fatima-Azzahra Delmani, Asma I. Mahmod","doi":"10.1515/znb-2023-0050","DOIUrl":"https://doi.org/10.1515/znb-2023-0050","url":null,"abstract":"A series of 3-chloro-1-aryl-4-dihydro-2<jats:italic>H</jats:italic>-pyrrolo[2,3-<jats:italic>b</jats:italic>]quinoxalin-2-ones and 3-chloro-1-aryl-6,7-dimethyl-1,4-dihydro-2<jats:italic>H</jats:italic>-pyrrolo[2,3-<jats:italic>b</jats:italic>]quinoxalin-2-ones was prepared by the condensation of <jats:italic>o</jats:italic>-phenylenediamine or 4,5-dimethyl-1,2-aminobenzene with <jats:italic>N</jats:italic>-aryl-3,4-dichloro-maleimides. All the prepared quinoxalines were tested for their antitumor activity against three human cancer cell lines (prostate cells PC3, colorectal cells Caco-2, and cervical cells HeLa), and a mammalian cell line (Vero cells). The compounds were also tested for their antibacterial properties against three different bacterial cells <jats:italic>Escherichia coli</jats:italic>, <jats:italic>Bacillus spizizenii,</jats:italic> and <jats:italic>Pseudomonas aeruginosa</jats:italic>. The compounds 3c, 3d, 3g, 3h, 3i and 4a, 4b, 4h showed anti-proliferative activity against the tested cell lines. Regarding their antibacterial activity, compounds 3a, 3g, 4a, and 4h showed inhibitory activity against <jats:italic>E. coli</jats:italic>, and <jats:italic>B. spizizenii</jats:italic> only.","PeriodicalId":23831,"journal":{"name":"Zeitschrift für Naturforschung B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140573862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sophie Hund, Oscar Gómez-Cápiro, Holger Ruland, Eva M. Heppke, Martin Lerch
Ni2Mo3N was synthesized by ammonolysis of NiMoO4, prepared by a sol-gel-based modified Pechini route. X-ray powder diffraction measurements confirmed that Ni2Mo3N crystallizes in a filled β-Mn type (cubic space group P4132) with a lattice parameter of a = 6.6338 Å. Group theoretical methods were applied to elucidate the relation between the crystal structure of Ni2Mo3N and that of the rock salt type. The high-temperature behavior was investigated in-situ by X-ray diffraction measurements in flowing ammonia gas at temperatures up to 875 °C. Ni2Mo3N exhibits significant catalytical activity for ammonia decomposition, which is critically discussed in comparison to literature.
{"title":"Ni2Mo3N: crystal structure, thermal properties, and catalytic activity for ammonia decomposition","authors":"Sophie Hund, Oscar Gómez-Cápiro, Holger Ruland, Eva M. Heppke, Martin Lerch","doi":"10.1515/znb-2023-0071","DOIUrl":"https://doi.org/10.1515/znb-2023-0071","url":null,"abstract":"Ni<jats:sub>2</jats:sub>Mo<jats:sub>3</jats:sub>N was synthesized by ammonolysis of NiMoO<jats:sub>4</jats:sub>, prepared by a sol-gel-based modified Pechini route. X-ray powder diffraction measurements confirmed that Ni<jats:sub>2</jats:sub>Mo<jats:sub>3</jats:sub>N crystallizes in a filled <jats:italic>β</jats:italic>-Mn type (cubic space group <jats:italic>P</jats:italic>4<jats:sub>1</jats:sub>32) with a lattice parameter of <jats:italic>a</jats:italic> = 6.6338 Å. Group theoretical methods were applied to elucidate the relation between the crystal structure of Ni<jats:sub>2</jats:sub>Mo<jats:sub>3</jats:sub>N and that of the rock salt type. The high-temperature behavior was investigated <jats:italic>in-situ</jats:italic> by X-ray diffraction measurements in flowing ammonia gas at temperatures up to 875 °C. Ni<jats:sub>2</jats:sub>Mo<jats:sub>3</jats:sub>N exhibits significant catalytical activity for ammonia decomposition, which is critically discussed in comparison to literature.","PeriodicalId":23831,"journal":{"name":"Zeitschrift für Naturforschung B","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140574031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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