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Electrochromics by Intramolecular Redox Switching of Single Bonds
Author(s) -
Hünig Siegfried,
Aldenkortt Sven,
Bäuerle Peter,
Briehn Christoph A.,
Schäferling Michael,
Perepichka Igor F.,
Stalke Dietmar,
Walfort Bernhard
Publication year - 2002
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 - 10.1002/1099-0690(200205)2002:10<1603::aid-ejoc1603>3.0.co;2-9
Subject(s) - chemistry , intramolecular force , redox , absorption (acoustics) , electron transfer , electrochromism , photochemistry , ring (chemistry) , absorption spectroscopy , red shift , crystallography , stereochemistry , inorganic chemistry , organic chemistry , electrode , physics , quantum mechanics , galaxy , acoustics
Compounds of the general structure presented in Scheme 1 are proposed as electrochromic systems (ESs) in which reversible electron transfer is associated with breaking or forming of single bonds. In contrast to classical ESs, both redox states represent closed‐shell systems. Whereas type OL/CS ( O pen form − L ong‐wavelength absorption/ C losed form − S hort‐wavelength absorption) has already been demonstrated, this paper presents examples of the OS/CL type, in which the long‐wavelength absorption is displayed by the ring‐closed form. Bis(azines) RED‐8 , RED‐13 , RED‐16 , and RED‐17 , as well as the bis(amines) RED‐22 , RED‐23 , and RED‐24 were prepared and characterized by their cyclic voltammograms (CV) and spectroelectrograms (SE). Except for the case of RED‐24 , the reversible overall transfer of two electrons is connected to switching of a single C−C or N−N bond. This reaction is not restricted to an entropically favorable transannular reaction ( OX‐8 2+ , OX‐16 2+ , and OX‐17 2+ ) but also occurs with the formation of five‐ ( OX‐13 2+ and OX‐23 2+ ) and certain six‐membered rings ( OX‐22 2+ ). These results suggest that the OS/CL general structure type should allow broad variation both in redox potentials and in ranges of color, similarly to the OL/CS type. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)