Helvetica Chimica Acta最新文献_第7页

Photoinduced Energy Transfer via an Atropisomeric Molecular Bridge 通过atrosomomer分子桥的光诱导能量转移

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-12-04 DOI: 10.1002/hlca.202400163

Dominik Lotter, Annika Huber, Joël Wellauer, Oliver S. Wenger, Christof Sparr

引用次数: 0

Stability of Shielded Pentacenes under Ambient Conditions 环境条件下屏蔽五苯的稳定性

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-11-28 DOI: 10.1002/hlca.202400161

Philipp Ludwig, Paul Kilian, Patrick Mayerhofer, Nikolai Hippchen, Frank Rominger, Jan Freudenberg, Uwe H. F. Bunz

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Radical C4−H Arylation of 1,4-Dihydropyridines with Cyanoarenes 1,4-二氢吡啶与氰芳烃的自由基C4−H芳基化反应

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-11-20 DOI: 10.1002/hlca.202400162

Huaixuan Guo, Shiqin Qiu, Peng Xu

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Cover Picture: (Helv. Chim. Acta 11/2024) 封面图片：（Helv.）

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-11-16 DOI: 10.1002/hlca.202471101

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The pKa of Water and the Fundamental Laws Describing Solution Equilibria: An Appeal for a Consistent Thermodynamic Pedagogy 水的 pKa 和描述溶液平衡的基本规律：呼吁采用一致的热力学教学法

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-11-13 DOI: 10.1002/hlca.202400103

Thomas L. Neils, Stephanie Schaertel, Todd P. Silverstein

{"title":"The pKa of Water and the Fundamental Laws Describing Solution Equilibria: An Appeal for a Consistent Thermodynamic Pedagogy","authors":"Thomas L. Neils, Stephanie Schaertel, Todd P. Silverstein","doi":"10.1002/hlca.202400103","DOIUrl":"https://doi.org/10.1002/hlca.202400103","url":null,"abstract":"A recurring misconception in some textbooks and research papers has led to an abandonment of fundamental physical laws when describing a subset of acid-base equilibria, especially regarding the role of the solvent. In the specific case of the autoprotolysis of water, experiments and theoretical calculations prove that the Kw of water at 25 °C, 1.00×10−14, is identical to its acid ionization constant, Ka. Nevertheless, several articles have been published erroneously purporting to give theoretical proof that the Ka of water is 10−15.743 (1.81×10−16) and that the Ka of the aqueous proton (hydronium ion) is 55.3 rather than 1.00. Here we argue that using the incorrect numbers has pedagogical implications beyond those of a simple error. Arguments for the incorrect Ka and pKa values require a misapplication of Henry's law and violate long-standing methods that use Raoult's law and the conservation of matter to describe the behavior of solutions. As a result, chemistry students may be asked to accept one set of physical principles in one course and another set in another course. Here we argue for adherence to fundamental physical laws governing solution equilibria as applied to the autoprotolysis of water and all aqueous acid base equilibria.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"107 11","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202400103","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Suppressing Inversion of a Chiral Polycyclic Aromatic Aza Monkey Saddle by Molecular Editing 通过分子编辑抑制手性多环芳香族氮杂环猴鞍的反转

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-11-04 DOI: 10.1002/hlca.202400158

Tobias Kirschbaum, Simone Felicia Ebel, Frank Rominger, Michael Mastalerz

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Total Synthesis of Tagitinins, Goyazensolide and Related Furanoheliangolides and their Covalent Interaction with Importin-5 (IPO5) Tagitinins 、Goyazensolide 和相关呋喃香葱内酯的全合成及其与导入素-5 (IPO5) 的共价相互作用

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-10-27 DOI: 10.1002/hlca.202400122

Weilong Liu, Rémi Patouret, Elsa Peev, Sofia Barluenga, Nicolas Winssinger

{"title":"Total Synthesis of Tagitinins, Goyazensolide and Related Furanoheliangolides and their Covalent Interaction with Importin-5 (IPO5)","authors":"Weilong Liu, Rémi Patouret, Elsa Peev, Sofia Barluenga, Nicolas Winssinger","doi":"10.1002/hlca.202400122","DOIUrl":"https://doi.org/10.1002/hlca.202400122","url":null,"abstract":"Herein, we detail an extension of our research on the synthesis of a small library of furanoheliangolides and the characterization of the covalent interaction between goyazensolide and IPO5. Using a build-couple-pair strategy, we assembled a small library of germacrene-type lactones and diversified them into eight groups of structurally different analogues. The germacrene lactones were synthesized using Sonogashira coupling and Barbier-type macrocyclization, while the furanoheliangolides were further elaborated through gold-catalyzed transannulation followed by esterification. This synthetic approach enabled the generation of a goyazensolide alkyne-tagged cellular probe, which was used to identify the selective binding between goyazensolide and the oncoprotein importin-5 (IPO5). Mass spectrometry analysis of the proteolytic digest from the reaction between the goyazensolide probe and a recombinant IPO5 indicated a covalent engagement at Cys560 of IPO5, which was confirmed by site-directed mutagenesis.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"107 11","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202400122","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Electronic Structures of Late versus Early Transition Metal Imido Complexes from 15N-NMR Signatures 从 15N-NMR 信号看晚期过渡金属亚胺配合物与早期过渡金属亚胺配合物的电子结构

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-10-27 DOI: 10.1002/hlca.202400142

Yuya Kakiuchi, Christophe Copéret

{"title":"Electronic Structures of Late versus Early Transition Metal Imido Complexes from 15N-NMR Signatures","authors":"Yuya Kakiuchi, Christophe Copéret","doi":"10.1002/hlca.202400142","DOIUrl":"https://doi.org/10.1002/hlca.202400142","url":null,"abstract":"Imido ligand is a ubiquitous motif in organometallic chemistry, serving roles spanning from ancillary ligands to reactive sites. The nature of M=N bond is highly depended on the metal centres and their d-electron configuration, with late transition metal (TM) imido complexes exhibiting contrasting features when compared to their early TM analogues. Envisioning to uncover general electronic descriptor for the nature of imido ligands, we computationally investigate the solid-state 15N NMR signatures of late TM imido complexes with various central metals, geometries and d-electron counts, and compare them against these of the corresponding early TM systems. The spectroscopic signatures are mostly driven by the presence of filled, π-symmetry orbitals in late TM imido complexes, suggesting the development of high-lying π(M=N) and low-lying σ/σ*(M=N) orbitals. This contrasts with what is observed for the reported early TM systems, for which high-lying σ-type orbitals determine the NMR signature. Noteworthily, Ni- and Pd-imido complexes with formal d10 configurations exhibit highly asymmetric nitrogen-15 NMR signature with extremely deshielded principal components, because of the presence of filled, high-lying antibonding π*(M=N) orbitals, consistent with their high reactivity. The sensitive response of 15N NMR signature to the nature of metal sites further highlights that chemical shift is a useful reactivity descriptor.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"107 11","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202400142","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Cover Picture: (Helv. Chim. Acta 10/2024) 封面图片：（Helv.）

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-10-25 DOI: 10.1002/hlca.202471001

引用次数: 0

Reversible Grafting in Surface Organometallic Chemistry with a Late Transition-Metal Amidinate Precursor 用晚过渡金属酰胺酸盐前驱体进行表面有机金属化学的可逆接枝

IF 1.5 4区化学

Helvetica Chimica Acta Pub Date : 2024-10-17 DOI: 10.1002/hlca.202400133

Christian Ehinger, Christophe Copéret

{"title":"Reversible Grafting in Surface Organometallic Chemistry with a Late Transition-Metal Amidinate Precursor","authors":"Christian Ehinger, Christophe Copéret","doi":"10.1002/hlca.202400133","DOIUrl":"https://doi.org/10.1002/hlca.202400133","url":null,"abstract":"Supported catalysts are central to industrial catalytic processes. While traditional synthesis methods often yield poorly defined materials, thus complicating structural elucidation, Surface Organometallic Chemistry (SOMC) offers a solution, producing well-defined structures. Recent advances in SOMC precursor development have shown that amidinate-based complexes are a privileged class of precursors to generate supported metallic nanoparticles. In that context, this study investigates the grafting mechanism of a prototypical amidinate precursor, Ir(COD)(DIA) (1-Ir), onto SiO2. Unique to amidinate complexes, grafting is shown to occur without ligand release, creating a reversible covalent bond. Using tris(tert-butoxy)silanol as a molecular analogue for a silanol group on SiO2, the structure of the grafted species is elucidated by single X-Ray diffraction, comparison of IR spectroscopy, and X-Ray absorption spectroscopy (XAS) data. The reversibility of the reaction with O−H groups is demonstrated using variable-temperature NMR spectroscopy, IR spectroscopy, and is supported by DFT calculations. Notably, we show that a partial degrafting is also possible at elevated temperatures under vacuum.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"107 12","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202400133","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142861456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0