Helvetica Chimica Acta最新文献_第5页

How (not) to Cage an Electron: The Perfluoro Cage Effect as an Extrinsic Molecular Property 如何（不）笼养电子：全氟笼效应作为一种外在分子性质

IF 1.8 4区化学

Helvetica Chimica Acta Pub Date : 2026-04-16 Epub Date: 2026-02-28 DOI: 10.1002/hlca.202500179

Andreas Riedmiller, Christian Mück-Lichtenfeld, Johannes Neugebauer

{"title":"How (not) to Cage an Electron: The Perfluoro Cage Effect as an Extrinsic Molecular Property","authors":"Andreas Riedmiller, Christian Mück-Lichtenfeld, Johannes Neugebauer","doi":"10.1002/hlca.202500179","DOIUrl":"https://doi.org/10.1002/hlca.202500179","url":null,"abstract":"The notion of a (molecular) electron cage was coined for the unique hosting capacity of perfluorocubane, suggesting the “encapsulation of an electron” within the highly symmetric molecular framework. Extensions to this occurrence of a perfluoro cage effect (PCE) have been found in a variety of different cage structures, showing a remarkable transferability within the chemical subspace of perfluorinated prismanes and fullerens. Classifications of this cage effect based on Sigma Stellation fail for extended carbon frameworks, whereas Baders Atoms-in-Molecules analysis of non-nuclear attractors is inconclusive for smaller systems. Our investigation of the electronic structure within the molecular cage of perfluorocubane does not support the hypothesis of a caged electron as the common cause of the unique electron affinity characteristic for the PCE. Instead, we observe a central confining nodal surface within the spin density for perfluorocubane, which also occurs for any other radical anion of the aforementioned chemical subspace considered here. The association of the spin density to the singly occupied molecular orbital of a corresponding restricted-open-shell Kohn–Sham reference system enables us to construct a quantitative single-particle model that captures the main tendencies of the vertical electron affinity on the symmetry and size of the system. The derivation is based on the so-called nodal variational principle and thereby clarifies the effectiveness of a confined particle model for the PCE without any reference to the encapsulation of an electron.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"109 4","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202500179","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147686307","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

Diterpenoid Diversity across Land Plants 陆地植物的二萜多样性

IF 1.8 4区化学

Helvetica Chimica Acta Pub Date : 2026-04-16 Epub Date: 2026-02-23 DOI: 10.1002/hlca.202500222

Anita Berg, Chad K. Papenfuhs, Amy E. Fraley

{"title":"Diterpenoid Diversity across Land Plants","authors":"Anita Berg, Chad K. Papenfuhs, Amy E. Fraley","doi":"10.1002/hlca.202500222","DOIUrl":"https://doi.org/10.1002/hlca.202500222","url":null,"abstract":"The diverse array of diterpenoid natural products stems from the ease of manipulating the promiscuity of diterpene cyclases. These enzymes are able to generate a vast array of structurally distinct diterpene skeletons from a common precursor, such as geranylgeranyl diphosphate, through subtle modifications in their active sites. Even minor amino acid substitutions can reshape the contour of the active site or alter the stabilization of key carbocation intermediates, leading to the emergence of new product profiles. This capacity for functional plasticity allows diterpene cyclases to rapidly explore chemical space, providing a rich assortment of scaffolds for development and persistence via natural selection. As a result, gene duplication followed by neofunctionalization of diterpene cyclases has driven the expansion of terpenoid repertoires across plant lineages, contributing to ecological diversification and specialized metabolic functions such as defense, communication, and adaptation to environmental stress. Here we will focus on the understudied bryophyte terpenome from structural diversification at the molecular level to regulation of biosynthetic pathways at the macroorganism level.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"109 4","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202500222","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147686336","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

IF 1.8 4区化学

Helvetica Chimica Acta Pub Date : 2026-04-08

引用次数: 0

IF 1.8 4区化学

Helvetica Chimica Acta Pub Date : 2026-04-08

引用次数: 0

IF 1.8 4区化学

Helvetica Chimica Acta Pub Date : 2026-04-04

引用次数: 0

IF 1.8 4区化学

Helvetica Chimica Acta Pub Date : 2026-04-01

引用次数: 0

IF 1.8 4区化学

Helvetica Chimica Acta Pub Date : 2026-03-31

引用次数: 0

IF 1.8 4区化学

Helvetica Chimica Acta Pub Date : 2026-03-25

引用次数: 0

π-Expanded Fluoranthenes as Chromophores With Tailored Properties π-膨化荧光蒽作为可调性质的发色团

IF 1.8 4区化学

Helvetica Chimica Acta Pub Date : 2026-03-15 Epub Date: 2026-01-08 DOI: 10.1002/hlca.202500227

Silas C. Eiden, Erik Misselwitz, John Bergner, Frank Rominger, Milan Kivala

{"title":"π-Expanded Fluoranthenes as Chromophores With Tailored Properties","authors":"Silas C. Eiden, Erik Misselwitz, John Bergner, Frank Rominger, Milan Kivala","doi":"10.1002/hlca.202500227","DOIUrl":"https://doi.org/10.1002/hlca.202500227","url":null,"abstract":"A series of π-expanded fluoranthene scaffolds, selectively decorated with electron donors and acceptors, were synthesized through copper-catalyzed reactions using the corresponding nucleophiles and brominated precursors. X-ray crystallography revealed that substitution and degree of cyclization significantly impact the overall molecular geometry and solid-state packing of the compounds. UV/Vis absorption and emission spectroscopy, as well as electrochemistry, provided insights into the impact of substitution on the optoelectronic and redox properties. The substitution generally leads to bathochromically shifted absorption and emission bands covering the entire visible region of the electromagnetic spectrum. Under electrochemical conditions, the compounds undergo reversible oxidations and reductions, with the potentials being highly sensitive to substitution. The experimental data were corroborated by density functional theory (DFT) calculations indicating effective modulation of the frontier molecular orbital levels upon functionalization.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"109 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202500227","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147618080","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

Phosphoramidate and Silyl Amine Mediated Synthesis of Isocyanide Cyclopentadienone Iron Complexes 磷酰胺和硅胺介导的异氰化物环戊二酮铁配合物的合成

IF 1.8 4区化学

Helvetica Chimica Acta Pub Date : 2026-03-15 Epub Date: 2026-01-26 DOI: 10.1002/hlca.202500203

André Bütikofer, Daniel Svoboda, Joël Landis, Peter Chen

{"title":"Phosphoramidate and Silyl Amine Mediated Synthesis of Isocyanide Cyclopentadienone Iron Complexes","authors":"André Bütikofer, Daniel Svoboda, Joël Landis, Peter Chen","doi":"10.1002/hlca.202500203","DOIUrl":"https://doi.org/10.1002/hlca.202500203","url":null,"abstract":"A synthetic procedure for the preparation of isocyanide cyclopentadienone iron complexes using the corresponding tricarbonyl complexes and primary amines as starting materials is described. By transforming the primary amines into deprotonated phosphoramidates or silyl amines, the CO ligands can be replaced by CNR ligands by abstracting the CO oxygen atom and replacing it with an NR fragment, with concomitant formation of phosphates or silanols as the thermodynamic driving force. The phosphoramidate route, using RNHP(O)(OEt)2, works well for R = alkyl, but fails for R = aryl, presumably due to the reduced nucleophilicity of the intermediate deprotonated phosphoramidate. Aromatic isocyanide ligands are accessible by using silyl amines ArNHTMS (Ar = aryl, TMS = trimethylsilyl) instead. The disclosed procedure has the advantage that the free isocyanide ligands themselves do not need to be isolated, which circumvents the use of strongly unpleasant smelling chemicals. Catalytic transfer hydrogenation reactions show that, under the same reaction conditions, the monoisocyanide complexes perform significantly worse than the corresponding tricarbonyl complexes. Kinetic monitoring revealed that fast catalyst decomposition is responsible for the lower performance. The reaction mechanism of the C≡O/C≡NR transformation was additionally investigated by DFT calculations.","PeriodicalId":12842,"journal":{"name":"Helvetica Chimica Acta","volume":"109 3","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/hlca.202500203","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147618095","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