title: Essential factors for control of the equilibrium in the reversible rearrangement of M₃N@I(h)-C₈₀ fulleropyrrolidines: exohedral functional groups versus endohedral metal clusters.
abstract: The effects of exohedral moieties and endohedral metal clusters on the isomerization of M3N@I(h)-C80 products from the Prato reaction through [1,5]-sigmatropic rearrangement were systematically investigated by using three types of fulleropyrrolidine derivatives and four different endohedral metal clusters. As a result, all types of derivatives provided the same ratios of the isomers for a given trimetallic nitride template (TNT) as the thermodynamic products, thus indicating that the size of the endohedral metal clusters inside C80 was the single essential factor in determining the equilibrium between the [6,6]-isomer (kinetic product) and the [5,6]-isomer. In all the derivatives, the [6,6]- and [5,6]-Prato adducts with larger metal clusters, such as Y3N and Gd3N, were equally stable, which is in good agreement with DFT calculations. The reaction rate of the rearrangement was dependent on both the substituent of exohedral functional groups and the endohedral metal-cluster size. Further DFT calculations and (13)C NMR spectroscopic studies were employed to rationalize the equilibrium in the rearrangement between the [6,6]- and [5,6]-fulleropyrrolidines.
authors.affiliation: Laboratorium für Organische Chemie, ETH-Zürich, Vladimir-Prelog-Weg 3, CH-8093 Zürich (Switzerland), Fax: (+41) 44 633-1235.
authors.forename: Safwan
authors.initials: S
authors.lastname: Aroua
authors.forename: Marc
authors.initials: M
authors.lastname: Garcia-Borràs
authors.forename: Sílvia
authors.initials: S
authors.lastname: Osuna
authors.forename: Yoko
authors.initials: Y
authors.lastname: Yamakoshi
mesh_terms: D061565:Cycloaddition Reaction; D037741:Fullerenes / Q000737:chemistry*; D007536:Isomerism; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D011759:Pyrrolidines / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D037741:Fullerenes; D008670:Metals; D011759:Pyrrolidines
keywords: DFT calculations; Prato reaction; fullerenes; isomerization; nitrogen heterocycles