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Synthesis, Properties, and Electron Transfer Studies of Ferrocenyl Thiophenes
Author(s) -
Poppitz Elisabeth A.,
Hildebrandt Alexander,
Korb Marcus,
Schaarschmidt Dieter,
Lang Heinrich
Publication year - 2014
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201400352
Subject(s) - thiophene , moiety , chemistry , acceptor , ferrocene , redox , crystallography , electrochemistry , ligand (biochemistry) , electron acceptor , electron donor , single crystal , negishi coupling , stereochemistry , medicinal chemistry , photochemistry , catalysis , organic chemistry , physics , electrode , condensed matter physics , biochemistry , receptor
For a series of ferrocenyl thiophenes of type Fe(η 5 ‐C 5 H 4 ‐(4‐ R ‐ c C 4 H 2 S‐3‐yl))(η 5 ‐C 5 H 4 ‐(C 6 H 3 ‐3,5‐(CF 3 ) 2 ) [ R = H ( 3a ), OMe ( 4a )], Fe(η 5 ‐C 5 H 4 ‐(4‐ R ‐ c C 4 H 2 S‐3‐yl)(η 5 ‐C 5 H 4 ‐CHO) [ R = H ( 3b ), OMe ( 4b )], and Fe(η 5 ‐C 5 H 4 ‐(4‐ R ‐ c C 4 H 2 S‐3‐yl)(η 5 ‐C 5 H 4 ‐C≡N) [ R = H ( 3c ), OMe ( 4c )], the influence of electron‐withdrawing substituents at the ferrocenyl moiety and electron‐donating groups at the thiophene unit on the electronic behavior of 3a – c and 4a – c is reported. The coupling of the ferrocenyl and the thiophene moieties has been realized using the Negishi C , C cross‐coupling reaction protocol. Compounds 3a and 4c were structurally characterized by single‐crystal X‐ray diffraction studies. In electrochemical measurements the ferrocenyl redox potential depends on the particular substitution at the ferrocenyl and the thiophene unit. Moreover, UV/Vis/NIR studies showed ligand‐to‐metal charge transfer (LMCT) interactions, which occur after oxidation and are shifted bathochromically as the donor‐acceptor energy gap decreases. Using different substituents, possessing electron‐withdrawing or donating capabilities, allows adjusting the energy difference between the ferrocenium‐acceptor unit and the donating thiophene system.