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Oxidation‐Triggered Ring‐Opening Metathesis Polymerization
Author(s) -
Savka Roman,
Foro Sabine,
Gallei Markus,
Rehahn Matthias,
Plenio Herbert
Publication year - 2013
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.201300868
Subject(s) - chemistry , ruthenium , ferrocene , metathesis , polymerization , pyridine , medicinal chemistry , catalysis , polymer chemistry , redox , imine , amine gas treating , salt metathesis reaction , cyclooctene , ring opening metathesis polymerisation , ring (chemistry) , organic chemistry , electrochemistry , polymer , electrode
Eight new N ‐Hoveyda‐type complexes were synthesized in yields of 67–92 % through reaction of [RuCl 2 (NHC)(Ind)(py)] (NHC=1,3‐bis(2,4,6‐trimethylphenylimidazolin)‐2‐ylidene (SIMes) or 1,3‐bis(2,6‐diisopropylphenylimidazolin)‐2‐ylidene (SIPr), Ind=3‐phenylindenylid‐1‐ene, py=pyridine) with various 1‐ or 1,2‐substituted ferrocene compounds with vinyl and amine or imine substituents. The redox potentials of the respective complexes were determined; in all complexes an iron‐centered oxidation reaction occurs at potentials close to E =+0.5 V. The crystal structures of the reduced and of the respective oxidized Hoveyda‐type complexes were determined and show that the oxidation of the ferrocene unit has little effect on the ruthenium environment. Two of the eight new complexes were found to be switchable catalysts, in that the reduced form is inactive in the ring‐opening metathesis polymerization of cis ‐cyclooctene (COE), whereas the oxidized complexes produce polyCOE. The other complexes are not switchable catalysts and are either inactive or active in both reduced and oxidized states.