Doubly-Reduced Pentacene in Different Coordination Environments: X-ray Crystallographic and Theoretical Insights into Structural and Electronic Changes.

Autor: Pennachio M; Department of Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA., Zhou Z; Department of Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA.; School of Materials Science and Engineering, Tongji University, 4800 Cao'an Road, Shanghai, 201804, P. R. China., Wei Z; Department of Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA., Liu S; Department of Chemistry, Illinois Institute of Technology, Chicago, IL 60616, USA., Rogachev AY; Department of Chemistry, Illinois Institute of Technology, Chicago, IL 60616, USA., Petrukhina MA; Department of Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA.
Jazyk: angličtina
Zdroj: Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2022 Feb 16; Vol. 28 (9), pp. e202104194. Date of Electronic Publication: 2022 Jan 12.
DOI: 10.1002/chem.202104194
Abstrakt: Chemical reduction of pentacene (C 22 H 14 , 1) with Group 1 metals ranging from Li to Cs revealed that 1 readily undergoes a two-fold reduction to afford a doubly-reduced 1 2- anion in THF. With the help of 18-crown-6 ether used as a secondary coordinating agent, five π-complexes of 1 2- with different alkali metal counterions have been isolated and fully characterized. This series of complexes enables the first evaluation of alkali-metal ion binding patterns and structural changes of the 1 2- dianion based on the crystallographically confirmed examples. The difference in coordination of the smallest Li + ion vs. heavier Group 1 congeners has been demonstrated. In addition, the use of benzo-15-crown-5 in the reaction of 1 with Na metal allowed the isolation of the unique solvent-separated ion product with a "naked" dianion, 1 2- . The detailed structural analyses of the series revealed the C-C bond alteration and core deformation of pentacene upon two-fold reduction and complexation. The negative charge localization at the central six-membered ring of 1 2- identified by theoretical calculations corroborates with the X-ray crystallographic results. Subsequent in-depth theoretical analysis provided a detailed description of changes in the electronic structure and aromaticity of pentacene upon reduction.
(© 2021 Wiley-VCH GmbH.)
Databáze: MEDLINE
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