title: Synthesis and reactivity of [penta(4-halogenophenyl)cyclopentadienyl][hydrotris(indazolyl)borato]ruthenium(II) complexes: rotation-induced Fosbury flop in an organometallic molecular turnstile.
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.
authors.affiliation: NanoSciences Group, CEMES-CNRS, 29 rue Jeanne Marvig, BP 94347, 31055 Toulouse Cedex 4, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Carella
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Launay
authors.forename: Romuald
authors.initials: R
authors.lastname: Poteau
authors.forename: Gwénaël
authors.initials: G
authors.lastname: Rapenne
mesh_terms: D001881:Borates / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D006846:Hydrocarbons, Halogenated / Q000138:chemical synthesis* / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D012015:Reference Standards; D012399:Rotation; D012428:Ruthenium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D001881:Borates; D006846:Hydrocarbons, Halogenated; D008024:Ligands; D009942:Organometallic Compounds; D012428:Ruthenium