An ate samarium complex containing two different kinds of reduced azobenzene species

Reaction of metallic samarium firstly with 2 equivalents of azobenzene in THF with the aid of catalytic amount of iodine and then with 1 equivalent of sodium cyclopentadienide successively afforded the title complex [(THF)3Na(μ-η5:η5-C5H5)(η2-PhNHNPh)Sm]2(μ-η2:η3-N2Ph2)2 (1). It was found that two-electron reduction and hydride-addition of azobenzene cooperated in the reaction. The hydride-addition reaction happened in the absence of any hydride-reagents. It is the first ate samarium–azobenzene complex and also the first samarium complex containing two different kinds of reduced azobenzene species.