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Title: Doubly‐Reduced Pentacene in Different Coordination Environments: X‐ray Crystallographic and Theoretical Insights into Structural and Electronic Changes
Abstract

Chemical reduction of pentacene (C22H14,1) with Group 1 metals ranging from Li to Cs revealed that1readily undergoes a two‐fold reduction to afford a doubly‐reduced12−anion in THF. With the help of 18‐crown‐6 ether used as a secondary coordinating agent, five π‐complexes of12−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 the12−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 of1with Na metal allowed the isolation of the unique solvent‐separated ion product with a “naked” dianion,12−. 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 of12−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.

 
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Award ID(s):
2003411 1726724
PAR ID:
10362869
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Chemistry – A European Journal
Volume:
28
Issue:
9
ISSN:
0947-6539
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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