Synthesis and Reactivity of [Penta(4-halogenophenyl)cyclopentadienyl][hydrotris(indazolyl)borato]ruthenium(II) Complexes: Rotation-Induced Fosbury Flop in an Organometallic Molecular Turnstile
✍ Scribed by Alexandre Carella; Jean-Pierre Launay; Romuald Poteau; Gwénaël Rapenne
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 478 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0947-6539
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✦ Synopsis
Abstract
The preparation of ruthenium(II) complexes coordinated to a penta(4‐halogeno)phenylcyclopentadienyl ligand and to the hydrotris(indazolyl)borate ligand are detailed. Our strategy involves first the coordination of the penta(4‐bromo)phenylcyclopentadienyl ligand by reaction with the ruthenium–carbonyl cluster followed by the coordination of the tripodal ligand. The pentabrominated precursor was successfully converted to the pentaiodinated derivative by using the Klapars–Buchwald methodology, applied for the first time on organometallic substrates. Cross‐coupling reactions were performed on both pentabromo and pentaiodo complexes to introduce in a single step the five peripheric ferrocenyl fragments required to obtain a potential molecular motor. The two ligands present in the ruthenium complexes undergo a correlated rotation that was established both experimentally by NMR experiments and an X‐ray diffraction study, and theoretically by DFT calculations. The potential‐energy curve obtained by DFT revealed the energy barrier of the gearing mechanism to be only 4.5 kcal mol^−1^. These sterically highly constrained complexes can be regarded as organometallic molecular turnstiles.