title: Phosphorus-containing hybrid calixphyrins: promising mixed-donor ligands for visible and efficient palladium catalysts.
abstract: Phosphorus-sulfur-containing hybrid calixphyrins were prepared by the BF3-promoted dehydrative condensation between sigma4-2,5-bis[(pyrrol-2-yl)methyl]phosphole and 2,5-bis[hydroxy(phenyl)methyl]thiophene. X-ray crystallographic analysis of the Pd-P,N2,S-hybrid calixphyrin complex revealed that the Pd center was coordinated by the four heteroatoms to adopt a distorted square planar geometry. The Pd complex, displaying a characteristic reddish purple color in solution, catalyzed the Heck reaction of bromoarenes with n-butyl acrylate with high efficiency at elevated temperatures.
authors.affiliation: Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan. matano@scl.kyoto-u.ac.jp
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Matano
authors.forename: Tooru
authors.initials: T
authors.lastname: Miyajima
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakabuchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Imahori
authors.forename: Noriaki
authors.initials: N
authors.lastname: Ochi
authors.forename: Shigeyoshi
authors.initials: S
authors.lastname: Sakaki