ions to a fourth-generation PAMAM dendrimer, chemical reduction of the metallic
ions to the NPs (e.g., NaBH 4 ), and finally adsorption of the NPs onto the mesoporous
SBA-15 support (Fig. 12). The reductive catalysts were efficient in promoting
hydrogenation of ethylene and pyrrole (Rh, Pt) [49, 50], ring-opening C-C bond
activation of strained three-membered rings (Rh) [51], reversible dehydrogenation/
hydrogenation of N-heterocycles (Pd, Pt) [52], enhanced activity and selectivity in
Hayashi-Ito aldol reaction of aldehydes and methyl isocyanoacetate (Au) compared
to the homogenous analogues [53], and ring-opening hydrogenative isomerization of
methylcyclopentane (Rh, Pt) [54]. These metal NPs were oxidized by the
hypervalent iodine species PhICl 2 , and the electrophilic catalysts obtained,
Fig. 12 (a) Preparation of PAMAM dendrimer-encapsulated NPs and subsequent immobilization
on mesoporous support. (b) Catalytic reactions using “heterogenizing” homogeneous catalysts.
Adapted with permission from [48, 49] Copyright 2008 and 2017 American Chemical Society,
respectively
142
M. Tanabe and K. Yamamoto
ions to the NPs (e.g., NaBH 4 ), and finally adsorption of the NPs onto the mesoporous
SBA-15 support (Fig. 12). The reductive catalysts were efficient in promoting
hydrogenation of ethylene and pyrrole (Rh, Pt) [49, 50], ring-opening C-C bond
activation of strained three-membered rings (Rh) [51], reversible dehydrogenation/
hydrogenation of N-heterocycles (Pd, Pt) [52], enhanced activity and selectivity in
Hayashi-Ito aldol reaction of aldehydes and methyl isocyanoacetate (Au) compared
to the homogenous analogues [53], and ring-opening hydrogenative isomerization of
methylcyclopentane (Rh, Pt) [54]. These metal NPs were oxidized by the
hypervalent iodine species PhICl 2 , and the electrophilic catalysts obtained,
Fig. 12 (a) Preparation of PAMAM dendrimer-encapsulated NPs and subsequent immobilization
on mesoporous support. (b) Catalytic reactions using “heterogenizing” homogeneous catalysts.
Adapted with permission from [48, 49] Copyright 2008 and 2017 American Chemical Society,
respectively
142
M. Tanabe and K. Yamamoto