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Electrochemical and Spectroscopic Studies on Triarylamine‐Polychlorotriphenylmethyl Dyads with Particularly Strong Triarylamine Donors
Author(s) -
Breimaier Stefanie,
Winter Rainer F.
Publication year - 2021
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.202100476
Subject(s) - chemistry , electron paramagnetic resonance , singlet state , cyclic voltammetry , spectroscopy , photochemistry , electrochemistry , tautomer , valence (chemistry) , acceptor , ultraviolet visible spectroscopy , amine gas treating , stereochemistry , excited state , nuclear magnetic resonance , organic chemistry , electrode , atomic physics , physics , condensed matter physics , quantum mechanics
Abstract We present two new donor‐acceptor dyads composed of a polychlorotriphenylmethyl radical ( PTM . ) as the acceptor (A) and bis(4‐dimethylaminophenyl)(phenyl)amine ( TPAN ) or 2,2’:6’,2’’:6’’,6‐trioxytriphenylamine ( TOTA ) as particularly electron‐rich triarylamine ( TAA ) donors (D). We assessed their electrochemical properties and electronic structures by cyclic voltammetry, UV/vis/NIR spectroscopy, EPR spectroscopy and quantum chemical calculations. By establishing the spectroscopic fingerprints of the oxidized and reduced forms, we probe for the possible coexistence of a zwitterionic TAA + ‐PTM − valence tautomer (VT), besides neutral TAA‐PTM . . UV/vis/NIR and EPR spectroscopic studies at variable temperature and in various solvents however provide no indication for such equilibria. Quantitative spin counting experiments by EPR spectroscopy and quantum chemical calculations indicate that the one‐electron oxidized forms of these dyads possess an open‐shell singlet ground state which is energetically slightly below the triplet state