title: Salt-Free Reduction of Nonprecious Transition-Metal Compounds: Generation of Amorphous Ni Nanoparticles for Catalytic C-C Bond Formation.
abstract: A salt-free procedure for the generation of a wide variety of metal(0) particles, including Fe, Co, Ni, and Cu, was achieved using 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene (1), which reduced the corresponding metal precursors under mild conditions. Notably, Ni particles formed in situ from the treatment of Ni(acac)2 (acac = acetylacetonate) with 1 in toluene exhibited significant catalytic activity for reductive C-C bond-forming reactions of aryl halides in the presence of excess amounts of 1. By examination of high-magnification transmission electron microscopy images and electron diffraction patterns, we concluded that amorphous Ni nanoparticles (Ni aNPs) were essential for the high catalytic activity.
authors.affiliation: Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka (Japan).
authors.forename: Taiga
authors.initials: T
authors.lastname: Yurino
authors.affiliation: Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka (Japan).
authors.forename: Yohei
authors.initials: Y
authors.lastname: Ueda
authors.affiliation: Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 5, Tsukuba, Ibaraki (Japan).
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Shimizu
authors.affiliation: Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), Central 5, Tsukuba, Ibaraki (Japan).
authors.forename: Shinji
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka (Japan).
authors.forename: Haruka
authors.initials: H
authors.lastname: Nishiyama
authors.affiliation: Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka (Japan).
authors.forename: Hayato
authors.initials: H
authors.lastname: Tsurugi
authors.affiliation: Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), Central 5, Tsukuba, Ibaraki (Japan). k.sato@aist.go.jp.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Sato
authors.affiliation: Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka (Japan). mashima@chem.es.osaka-u.ac.jp.
authors.forename: Kazushi
authors.initials: K
authors.lastname: Mashima
keywords: CC coupling; nanoparticles; nickel; organosilicon compounds; reductive coupling