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Synthesis of Optically Pure Helicene Metallocenes
Author(s) -
Akiyama Midori,
Nozaki Kyoko
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201611488
Subject(s) - helicene , ruthenocene , chemistry , moiety , racemization , enantiomer , ligand (biochemistry) , stereochemistry , ferrocene , crystallography , circular dichroism , organic chemistry , molecule , electrochemistry , electrode , biochemistry , receptor
Two types of ruthenocenes and a ferrocene coordinated by rac ‐9 H ‐cyclopenta[1,2‐ c :4,3‐ c ′]diphenanthrenyl anion(s), a [7]helicene with a cyclopentadienyl moiety at the center of its skeleton, were successfully synthesized: mono‐helicene ruthenocene 1 and its iron analogue 1 Fe with one [7]helicene ligand bound to the central metal, and bis‐helicene ruthenocene 2 with two [7]helicenes. Starting from a racemic mixture of the ligand precursor, rac ‐ 2 and meso ‐ 2 were obtained in a 7:3 ratio. Since the [7]helicene has a high racemization barrier, enantiomers of the complexes were isolated in their pure forms; they showed large optical rotations and intense circular dichroism (CD) responses.