A Crystallizable f-Element Tuck-in Complex:The Tuck-in Tuck-over Uranium Metallocene[(C5Me5)U{mu-eta 5:eta 1:eta 1-C5Me3(CH2)2}(mu-H)2U-(C5Me5)2]

摘要

One of the features of the C5Me_5~-group that makes it such a desirable ligand in organometallic chemistry is the fact that it is relatively inert to the C-H activation that often complicates the chemistry of C5H_5~-metallocene complexes.Although C5Me_5~-is more resistant to attack on the C-H bond,its methyl groups can be metalated with some highly reactive metal species.Since these C-H activated ligands arise from extremes in reactivity,they have been involved in unprecedented reactions.For example,the homogeneous C-H activation of methane was first discovered with[{(C5Me5)2LuMe}_n]based on a mechanism involving the"tucked-in"complex"[(C5Me5){C5Me4(CH2)}Lu]".Tuck-in intermediates have also played prominent roles in explaining the C-H activation in complexes such as[(C5Me5)2ScMe]and[(C5Me5)2Th(CH2CMe3)2].Despite the repeated use of tuck-in complexes in mechanistic schemes involving f elements,no spectroscopic or crystallographic evidence has ever been presented to support the existence of such an intermediate in a lanthanide or actinide complex.