Monomeric Thorium Dihydrido Complex: A Versatile Precursor to Actinide Metallacycles

The monomeric actinide dihydrido complex [(CpAr*)(Cp*)ThH2(THF)] (2) bearing the super-bulky penta-arylcyclopentadienyl (CpAr* = C5Ar*5, Ar* = 3,5-tBu2-C6H3) and pentamethylcyclopentadienyl (Cp* = C5Me5) ligands was obtained for the first time. Complex 2 underwent unique Th–H addition reactions with various unsaturated compounds to afford the corresponding five-membered metallacycles, including the first example of actinide metallacyclopentyne [(CpAr*)(Cp*)Th(PhCH–CC–CHPh)] (4).