Homoleptic rare-earth metal silylamide complexes Ln[N(SiMe3)(2)](3) (Ln = Y, La, Nd) were grafted onto a series of partially dehydroxylated periodic mesoporous silica (PMS) supports, SBA-15(-500) (d(p) = 7.9 nm), SBA-15LP(-500) (d(p) = 16.6 nm), and MCM-41(-500) (d(p) = 4.1 nm). The hybrid materials Ln[N(SiMe3)(2)](3)@PMS efficiently catalyze the intramolecular hydroamination/cyclization reaction of 2,2-dimethy1-4-penten-1-amine. Under the prevailing slurry conditions the metal size (Y > La > Nd), the pore size, and the particle morphology affect the catalytic performance. Material Y[N(SiMe3)(2)](3)@SBA-15LP(-500) displayed the highest activity (TOF = up to 420 h(-1) at 60 degrees C), with the extralarge pores minimizing restrictive product inhibition and substrate diffusion effects. The catalytic activity of Y[N(SiMe3)(2)](3)@SBA-15LP(-500) is found to be much higher than that of the molecular counterpart (TOF = up to 54 h(-1)), and its recyclability is demonstrated.