A mechanistic insight into metal-cluster π-envelopment: a dual binding mode involving bent and planar ligand-conformers.
Metal clusters are effectively stabilized by bridging π-coordination of planar π-conjugated unsaturated hydrocarbons. However, the mechanism of π-envelopment of a metal cluster has been elusive. By employing 1,2-bis(4-aryl-1,3-butadienyl)benzene as the π-conjugated ligand, we found that the π-envelopment of a Pd4 cluster proceeded in a stepwise manner, where the sp(2)-carbon ligands initially envelop the Pd4 cluster through a bent binding mode, and then isomerized to a thermodynamically more stable planar mode under mild heating or visible light irradiation. The involvement of a bent binding mode indicates the kinetically preferred coordination at the axial coordination site trans to a metal-metal bond.
Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan. mura@apc.titech.ac.jp.
Kohei
K
Masai
Katsunori
K
Shirato
Koji
K
Yamamoto
Yuki
Y
Kurashige
Tetsuro
T
Murahashi