Nanocrystalline Titania‐Supported Palladium(0) Nanoparticles for Suzuki–Miyaura Cross‐Coupling of Aryl and Heteroaryl Halides

Abstract

The Suzuki cross-coupling reaction of various aryl and heteroaryl halides with arylboronic and heteroarylboronic acids was studied using a titaniasupported palladium(0) catalyst at room temperature under air. The conversion and selectivity results obtained for many substrates were excellent and similar to those provided by more active or even homogeneous catalysts. The methodology is similarly effective using 2-bromo-3,4,5-trimethoxybenzaldehyde as the coupling partner and gave products in good yield. Furthermore, it has been shown that it is useful for the synthesis of terphenyl and tetraphenyls. The catalyst is quantitatively recovered from the reaction by simple filtration and reused for a number of cycles without significant loss of activity. Inductively coupled plasma (ICP) mass-spectrometric analysis of the filtrate from the reaction mixture demonstrated that the palladium metal hardly leached into the solution within the limits of the detector (1 ppm), thus suggesting that the present Suzuki-Miyaura reaction proceeded by heterogeneous catalysis.

Palladium nanoparticles supported on modified hollow Fe3O4@TiO2: Preparation, characterization, and catalytic activity in Suzuki cross‐coupling reactions

“…This indicates the presence of Pd NPs with the face‐centered cubic structure . Furthermore, the appearance of a peak at 39.9° confirms the presence of palladium in the metallic state . According to the Debye–Scherer formula, the average crystal size of hollo magnetite and Pd NPs were calculated as 34.5 and 7.2 nm, respectively, which are in good agreement with TEM observations (see below).…”

“…[44] Furthermore, the appearance of a peak at 39.9 confirms the presence of palladium in the metallic state. [45] According to the Debye-Scherer formula, the average crystal size of hollo magnetite and Pd NPs were calculated as 34.5 and 7.2 nm, respectively, which are in good agreement with TEM observations (see below). with a ramp of 5 C min −1 and revealed a weight loss of nearly 16% in the temperature range 120-800 C, whereas a weight loss of 7% was recorded for H-Fe 3 O 4 @TiO 2 in the same temperature range.…”

Bio‐Waste Corn–cob Cellulose Supported Poly(amidoxime) Palladium Nanoparticles for Suzuki‐Miyaura Cross‐Coupling Reactions

“…The ICP‐AES analysis showed 0.45 mmol/g of palladium was anchored onto the poly(amidoxime) ligand 2 . The cellulose supported palladium complex 2 was then treated with hydrazine hydrate to give dark black colour PdNs@PA (Ø=2.8 ± 6 nm) (Scheme ).…”

Development of Titanium Dioxide-Supported Pd Catalysts for Ligand-Free Suzuki–Miyaura Coupling of Aryl Chlorides

“…Furthermore, we developed heterogeneous Pd catalysts immobilized on a ligand-like tertiary amine polystyrene-divinylbenzene-based polymer for the ligand-free Suzuki-Miyaura coupling reaction of aryl chlorides [39,40]. The other category is polymers [34] or inorganics [31][32][33][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] without additional and coordinable functionalities, such as activated carbon [31][32][33], polystyrene [34], metal-organic frameworks [35], polyoxometalate [36] and titanium dioxide (TiO 2 ) [42][43][44][45][46][47][48][49][50].…”

“…Some TiO 2 -supported Pd catalysts have been applied to various organic and inorganic reactions such as the Suzuki-Miyaura reaction [42][43][44][45][46][47][48][49][50], hydrogenation [51][52][53][54][55][56][57][58] and Heck reaction [59]. However, the effect on the catalyst activity, depending on the difference of the TiO 2 crystal forms of TiO 2 -supported Pd catalysts toward cross-coupling reactions, has never been systematically evaluated, except for a report related to the oxidative homo coupling reaction of 4-methylpyridines in the presence of Pd oxide-loaded TiO 2 (PdO/TiO 2 ) as a catalyst [60].…”