Palladium Acetate and Pd Nanoparticles Loaded Hexamethylenetetramine Anchored Magnetically Retrievable Assemblies for Catalyzing Mizoroki‐Heck Type Mono and Gem‐Dicoupling Reactions

Abstract

Fe3O4 nanoparticles have been covalently coated and chemically modified to anchor hexamethylenetetramine (Fe3O4@HMTA) for hosting Pd catalysts such as palladium acetate and palladium nanoparticles. Thus prepared nanocatalyst assemblies have been extensively characterized for their chemical, physical, thermal and magnetic properties. The turnover number and turnover frequency of these catalysts in a model Mizoroki‐Heck coupling reaction involving 3‐acrylomorpholine and iodobenzene with a base as solvent are found to be 186 and 46 h−1, respectively, which are better than that reported in literature. This was attributed to synergistic effect of local basic environment of HMTA rich in tertiary nitrogen content. Gem‐dicoupled products are formed when reactions are performed in the presence of 1 equivalent of acrylate and 2.1 equivalents of aryl iodide, and gem‐hetero‐dicoupled product is obtained when reaction is performed in sequential manner. The mechanisms of the formation of the gem‐homo‐dicoupled and gem‐hetero‐dicoupled products have been elucidated by using the results obtained from NMR and single crystal X‐ray crystallography studies.

Pd(II)‐Functionalized Polymeric Shell Encapsulated on Magnetite Nanocatalysts for C−C Coupling Reactions

“…The different functionalized polymers such poly(ethyleneamine), DABCO, Hexamethylenetetramine, poly(ethylene glycol methacrylate phosphate), poly(acrylic acid), poly(propyleneimine) dendrimer, functionalized epoxy polymers, functionalized poly(vinylbenzyl chloride) etc. have been anchored on the magnetite nanoparticles for loading different homogeneouscatalysts after coating with appropriate linker group bearing silane [32–35] …”

“…have been anchored on the magnetite nanoparticles for loading different homogeneouscatalysts after coating with appropriate linker group bearing silane. [32][33][34][35] In the present work, we report a simple strategy for preparing the functionalized magnetite nanoparticles by polyacrylic acid (PAA) and triphenyl phosphine (PPh 3 ) (Fe 3 O 4 @PAAÀ PPh 3 ). Both PAA and PPh 3 are known to be the good sorbents for loading of palladium.…”