Premium
Multistep π Dimerization of Tetrakis( n ‐decyl)heptathienoacene Radical Cations: A Combined Experimental and Theoretical Study
Author(s) -
Ferrón Cristina Capel,
CapdevilaCortada Marçal,
Balster Russell,
Hartl František,
Niu Weijun,
He Mingqian,
Novoa Juan J.,
López Navarrete Juan T.,
Hernández Víctor,
Ruiz Delgado M. Carmen
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201402182
Subject(s) - dication , dimer , chemistry , electron paramagnetic resonance , radical ion , cyclic voltammetry , photochemistry , supramolecular chemistry , conjugated system , computational chemistry , crystallography , ion , electrochemistry , organic chemistry , crystal structure , physics , electrode , nuclear magnetic resonance , polymer
Radical cations of a heptathienoacene α,β‐substituted with four n ‐decyl side groups (D4T7 . + ) form exceptionally stable π‐dimer dications already at ambient temperature ( Chem. Comm . 2011 , 47 , 12622). This extraordinary π‐dimerization process is investigated here with a focus on the ultimate [D4T7 . + ] 2 π‐dimer dication and yet‐unreported transitory species formed during and after the oxidation. To this end, we use a joint experimental and theoretical approach that combines cyclic voltammetry, in situ spectrochemistry and spectroelectrochemistry, EPR spectroscopy, and DFT calculations. The impact of temperature, thienoacene concentration, and the nature and concentration of counteranions on the π‐dimerization process is also investigated in detail. Two different transitory species were detected in the course of the one‐electron oxidation: 1) a different transient conformation of the ultimate [D4T7 . + ] 2 π‐dimer dications, the stability of which is strongly affected by the applied experimental conditions, and 2) intermediate [D4T7] 2 . + π‐dimer radical cations formed prior to the fully oxidized [D4T7] 2 . + π‐dimer dications. Thus, this comprehensive work demonstrates the formation of peculiar supramolecular species of heptathienoacene radical cations, the stability, nature, and structure of which have been successfully analyzed. We therefore believe that this study leads to a deeper fundamental understanding of the mechanism of dimer formation between conjugated aromatic systems.