Please note that eDoc will be permanently shut down in the first quarter of 2021!      Home News About Us Contact Contributors Disclaimer Privacy Policy Help FAQ

Home
Search
Quick Search
Advanced
Fulltext
Browse
Collections
Persons
My eDoc
Session History
Login
Name:
Password:
Documentation
Help
Support Wiki
Direct access to
document ID:


          Institute: MPI für bioanorganische Chemie     Collection: MPI für bioanorganische Chemie     Display Documents



  history
ID: 712924.0, MPI für bioanorganische Chemie / MPI für bioanorganische Chemie
Möbius-Hückel topology switching in an expanded porphyrin cation radical as studied by EPR and ENDOR spectroscopy
Authors:Möbius, Klaus; Plato, Martin; Klihm, Gudrun; Laurich, Christoph; Savitsky, Anton; Lubitz, Wolfgang; Szyszko, Bartosz; Stepien, Marcin; Latos-Grazynski, Lechoslaw
Language:English
Date of Publication (YYYY-MM-DD):2015
Title of Journal:Physical Chemistry Chemical Physics
Journal Abbrev.:Phys.Chem.Phys.Chem.
Volume:17
Issue / Number:9
Start Page:6644
End Page:6652
Review Status:Internal review
Audience:Experts Only
Abstract / Description:The symmetry of the arrangement of objects has fascinated philosophers, artists and scientists for a long time, and still does. Symmetries often exist in nature, but are also created artificially, for instance by chemical synthesis of novel molecules and materials. The one-sided, non-orientable Mobius band topology is a paradigm of such a symmetry-based fascination. In the early 1960s, in synthetic organic chemistry the interest in molecules with Mobius symmetry was greatly stimulated by a short paper by Edgar Heilbronner. He predicted that sufficiently large [n]annulenes with a closed-shell electron configuration of 4n pi-electrons should allow for sufficient pi-overlap stabilization to be synthesizable by twisting them with a 1801 phase change into the Mobius symmetry of their hydrocarbon skeleton. In 2007, the group of Lechoslaw Latos-Grazynski succeeded in synthesizing the compound di-p-benzi[28]hexa-phyrin(1.1.1.1.1.1), compound 1, which can dynamically switch between Huckel and Mobius conjugation depending, in a complex manner, on the polarity and temperature of the surrounding solvent. This discovery of "topology switching'' between the two-sided (Huckel) and one-sided (Mobius) molecular state with closed-shell electronic configuration was based primarily on the results of NMR spectroscopy and DFT calculations. The present EPR and ENDOR work on the radical cation state of compound 1 is the first study of a ground-state open-shell system which exhibits a Huckel-Mobius topology switch that is controlled by temperature, like in the case of the closed-shell precursor. The unpaired electron interacting with magnetic nuclei in the molecule is used as a sensitive probe for the electronic structure and its symmetry properties. For a Huckel conformer with its higher symmetry, we expect - and observe - fewer ENDOR lines than for a Mobius conformer. The ENDOR results are supplemented by and in accordance with theoretical calculations based on density functional theory at the ORCA level.
Comment of the Author/Creator:Date: 2015, 2015
External Publication Status:published
Document Type:Article
Version Comment:Automatic journal name synchronization
Communicated by:N. N.
Affiliations:MPI für bioanorganische Chemie
External Affiliations:[Möbius,K.; Plato,M.;] Free Univ.Berlin, Fachbereich Phys., D-14195 Berlin, Germany.
[Szyszko,B.; Stepien,M.; Latos-Grazynski,L.] Uniwersytet Wroclawski, Wydzial Chem., PL-50383 Wroclaw, Poland.
Identifiers:ISI:000351435300055 [ID No:1]
ISSN:1463-9076 [ID No:2]
DOI:10.1039/C4CP05745G [ID No:3]
The scope and number of records on eDoc is subject to the collection policies defined by each institute - see "info" button in the collection browse view.