Oxidation triggers guest dissociation during reorganization of an FeL twisted parallelogram

• Published in: Chemical science (Cambridge) Vol. 11; no. 38; pp. 1399 - 144
• Main Authors: Plajer, Alex J, Rizzuto, Felix J, von Krbek, Larissa K. S, Gisbert, Yohan, Martínez-Agramunt, Víctor, Nitschke, Jonathan R
• Format: Journal Article
• Language: English
• Published: 07.10.2020
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/d0sc04352d

A three-dimensional Fe II 4 L 6 parallelogram was prepared from ferrocene-containing ditopic ligands. The steric preference of the bulky ferrocene cores towards meridional vertex coordination brought about this new structure type, in which the ferrocene units adopt three distinct conformations. The structure possesses two distinct, bowl-like cavities that host anionic guests. Oxidation of the ferrocene Fe II to ferrocenium Fe III causes rotation of the ferrocene hinges, converting the structure to an Fe II 1 L 1 + species with release of anionic guests, even though the average charge per iron increases in a way that would ordinarily increase guest binding strength. The degrees of freedom exhibited by these new structures - derived from the different configurations of the three ligands surrounding a meridional Fe II center and the rotation of ferrocene cores - thus underpin their ability to reconfigure and eject guests upon oxidation. An oxidation-triggered twist in its ferrocene ligands causes an Fe 4 L 6 parallelogram to release its guests and collapse into a high spin Fe 1 L 1 structure.