Ultra‐small and highly dispersed Pd nanoparticles inside the pores of ZIF‐8: Sustainable approach to waste‐minimized Mizoroki–Heck cross‐coupling reaction based on reusable heterogeneous catalyst

Abstract

The rapid development of nanomaterials, particularly advanced hybrid nanoparticles, has made new opportunities for the design and fabrication of high‐performance metal‐based catalysts. However, generating metal nanoparticles of desired size without aggregation is an important challenge for enhancing the catalytic activity of metal nanoparticles supported in the host matrix. In this work, a hybrid nanoporous material, namely Pd nanoparticles@N‐heterocyclic carbene@ZIF‐8, with a high internal surface area was successfully prepared using a dispersed anionic sulfonated N‐heterocyclic carbene–Pd(II) precursor inside the cavities of zeolitic imidazolate framework (ZIF‐8) using an impregnation approach followed by reduction with NaBH4. The anionic sulfonated N‐heterocyclic carbene was found to be a superb ligand for the stabilization of Pd nanoparticles in the pores of ZIF‐8. The resulting system was applied to the Mizoroki–Heck cross‐coupling reaction, in which the catalyst showed high catalytic activity under mild reaction conditions.

Sterically Hindered Phosphonium Salts: Structure, Properties and Palladium Nanoparticle Stabilization

“…Several studies have supported palladium nanocatalyst for cross-coupling reactions [ 27 , 28 ]. For example, in recent years, different types of nanoparticle support materials were investigated; for example, metal oxides [ 29 , 30 , 31 ], zeolites [ 32 , 33 , 34 ], carbons [ 35 , 36 , 37 ], ordered porous materials [ 38 , 39 ] and synthesized polymers [ 40 ] (e.g., ionic polymers [ 41 ]) and modified natural polymers [ 42 , 43 ]. There are several studies on mixed composition for palladium nanoparticle (PdNP) support [ 44 , 45 , 46 , 47 ], and the need for a rational design of catalyst support has been emphasized [ 48 , 49 ].…”

Synthesis of nano magnetic supported NHC-palladium and investigation of its applications as a catalyst in the Mizoroki-Heck cross-coupling reaction in H2O

“…(°C) Time (h) Solvent Yield b (%) Ref. 1 Fe 3 O 4 @Si–NHC–Pd 0.272 90 8 H 2 O 98 This work 2 NO 2 –NHC–Pd@Fe 3 O 4 1.0 80 6 MeCN 92 [ 21 ] 3 Pd NPs@NHC@ZIF-8 0.08 110 2.5 DMF-H 2 O 90 [ 22 ] 4 MnPs–NHC–Pd(II) 0.036 70 0.33 DMF 87 [ 19 ] 5 Hydrazon-pd@ZnO 0.26 130 1.5 DMF 85 [ 23 ] 6 PdCl 2 Kryptofix-5 0.9 130 24 DMF 16 [ 24 ] a Reaction conditions: Bromobenzene (1 mmol), styrene (1.2 mmol), base, Catalyst and solvent. b Yields of isolated product.…”

Magnetically recoverable nanostructured Pd complex of dendrimeric type ligand on the MCM-41: Preparation, characterization and catalytic activity in the Heck reaction

“…Among them, many heterogeneous catalysts containing Palladium have been designed and used in organic transformations (Tarahomi et al, 2019;Veisi et al, 2015a). Recently, many heterogeneous catalysts containing palladium which, Pd nanoparticles or complexes are involved as active catalyst sites have been used as catalyst in Heck reaction including polymer supported Pd complex (Schwarz et al, 2000), modified silica supported Pd complex (Clark et al, 2000), Pd anchored to layered double hydroxide (Choudary et al, 2002), Pd(II) salen complex covalently anchored to multiwalled carbon nanotubes , Pd(0)complex supported on boehmite nanoparticles (Ghorbani-Choghamarani et al, 2016), Pd(0)-S-methylisothiourea grafted onto mesoporous MCM-41 (Noori et al, 2016), ferromagnetic nanoparticle-supported palladium complex (Bahrami et al, 2017), Pd salen complex@cpgo (Ghabdian et al, 2018), Fe 2 O 3 @SiO 2 -(CH 2 ) 3 -Pdtc-Pd (Tashrifi et al, 2019) Pd nanoparticles inside the pores of Zif-8 (Azad et al, 2019), Pd-ninhydrin immobilized on magnetic nanoparticles (Hajjami and Shirvandi, 2020), Bnps@SiO 2 (CH 2 ) 3 NH-CC-Amp-Pd (0) (Khodamorady and Bahrami, 2020), Palladium anchored on guanidineterminated magnetic dendrimer (Niknam et al, 2020), Palladium complex supported on MCM-41 (Nikoorazm et al, 2020). Among them, silica support is highly regarded because of some advantages such as availability, excellent stability and ability of robust anchoring of organic moiety for providing catalyst site.…”