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Synthesis and Reactivity of [Penta(4‐halogenophenyl)cyclopentadienyl][hydrotris(indazolyl)borato]ruthenium(II) Complexes: Rotation‐Induced Fosbury Flop in an Organometallic Molecular Turnstile
Author(s) -
Carella Alexandre,
Launay JeanPierre,
Poteau Romuald,
Rapenne Gwénaël
Publication year - 2008
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.200800689
Subject(s) - ruthenium , cyclopentadienyl complex , ligand (biochemistry) , reactivity (psychology) , chemistry , cluster (spacecraft) , steric effects , group 2 organometallic chemistry , computational chemistry , crystallography , molecule , stereochemistry , catalysis , organic chemistry , medicine , biochemistry , receptor , alternative medicine , pathology , computer science , programming language
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.