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Iron in a Cage: Fixation of a Fe(II)tpy 2 Complex by Fourfold Interlinking
Author(s) -
Brandl Thomas,
Johannsen Sven,
Häussinger Daniel,
Suryadevara Nithin,
Prescimone Alessandro,
Bernhard Stefan,
Gruber Manuel,
Ruben Mario,
Berndt Richard,
Mayor Marcel
Publication year - 2020
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.202006340
Subject(s) - terpyridine , crystallography , ligand (biochemistry) , chemistry , schiff base , solvent , coordination sphere , stereochemistry , metal , crystal structure , organic chemistry , biochemistry , receptor
The coordination sphere of the Fe(II) terpyridine complex 1 is rigidified by fourfold interlinking of both terpyridine ligands. Profiting from an octa‐aldehyde precursor complex, the ideal dimensions of the interlinking structures are determined by reversible Schiff‐base formation, before irreversible Wittig olefination provided the rigidified complex. Reversed‐phase HPLC enables the isolation of the all‐ trans isomer of the Fe(II) terpyridine complex 1 , which is fully characterized. While temperature independent low‐spin states were recorded with superconducting quantum interference device (SQUID) measurements for both, the open precursor 8 and the interlinked complex 1 , evidence of the increased rigidity of the ligand sphere in 1 was provided by proton T 2 relaxation NMR experiments. The ligand sphere fixation in the macrocyclized complex 1 even reaches a level resisting substantial deformation upon deposition on an Au(111) surface, as demonstrated by its pristine form in a low temperature ultra‐high vacuum scanning tunneling microscope experiment.