title: Unprecedented isospecific 3,4-polymerization of isoprene by cationic rare earth metal alkyl species resulting from a binuclear precursor.
abstract: The isospecific 3,4-polymerization of isoprene has been achieved for the first time by use of a combination of a binuclear rare earth metal dialkyl complex, such as [Me2Si(C5Me4)(mu-PCy)YCH2SiMe3]2 (Cy = cyclohexyl), and an equimolar amount of [Ph3C][B(C6F5)4] as a catalyst system. A DFT calculation suggested that a binuclear monocationic monoalkyl species, such as [Me2Si(C5Me4)(mu-PCy)Y(mu-CH2SiMe3)Y(mu-PCy)(C5Me4)SiMe2]+, in which the alkyl group bridges the two metal centers, could be the true catalyst species.
authors.affiliation: Organometallic Chemistry Laboratory, RIKEN (The Institute of Physical and Chemical Research), Wako, Saitama 351-0198, Japan.
authors.forename: Lixin
authors.initials: L
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.forename: Zhaomin
authors.initials: Z
authors.lastname: Hou
mesh_terms: D002070:Butadienes / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D045782:Hemiterpenes / Q000737:chemistry*; D008674:Metals, Rare Earth / Q000737:chemistry*; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010420:Pentanes / Q000737:chemistry*
chemical_list: D002070:Butadienes; D002412:Cations; D045782:Hemiterpenes; D008674:Metals, Rare Earth; D009942:Organometallic Compounds; D010420:Pentanes; C005059:isoprene