title: Ligand-Controlled Synthesis of [3]- and [4]Cyclo-9,9-dimethyl-2,7-fluorenes through Triangle- and Square-Shaped Platinum Intermediates.
abstract: The syntheses of [3]- and [4]cyclo-9,9-dimethyl-2,7-fluorenes ([3] and [4]CFRs), cyclic trimer, and tetramers of 9,9-dimethyl-2,7-fluorene (FR), respectively, were achieved by the platinum-mediated assembly of FR units and subsequent reductive elimination of platinum. A triangle-shaped tris-platinum complex and a square-shaped tetra-platinum complex were obtained by changing the platinum ligand. The structure of the triangle complex was unambiguously determined by X-ray crystallographic analysis. Reductive elimination of each complex gave [3] and [4]CFRs. Two rotamers of [3]CFR were sufficiently stable at room temperature and were separated by chromatography. The physical properties of the CFRs were also investigated theoretically and experimentally.
authors.affiliation: Institute for Chemical Research, Kyoto University, Kyoto 611 0011 (Japan), Fax: (+81) 774-38-3067.|Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo (Japan).
authors.forename: Eiichi
authors.initials: E
authors.lastname: Kayahara
authors.affiliation: Institute for Chemical Research, Kyoto University, Kyoto 611 0011 (Japan), Fax: (+81) 774-38-3067.
authors.forename: Rui
authors.initials: R
authors.lastname: Qu
authors.affiliation: Institute for Chemical Research, Kyoto University, Kyoto 611 0011 (Japan), Fax: (+81) 774-38-3067.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Kojima
authors.affiliation: Institute for Chemical Research, Kyoto University, Kyoto 611 0011 (Japan), Fax: (+81) 774-38-3067.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Iwamoto
authors.affiliation: Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo (Japan).|Institute for Molecular Science, Myodaiji, Okazaki 444-8787 (Japan).
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Institute for Chemical Research, Kyoto University, Kyoto 611 0011 (Japan), Fax: (+81) 774-38-3067. yamago@scl.kyoto-u.ac.jp.|Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo (Japan). yamago@scl.kyoto-u.ac.jp.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Yamago
keywords: arenes; carbocycles; conjugation; density functional calculations; electronic structures