Palladium Nanoparticles Incorporated Thiazoline Functionalized Periodic Mesoporous Organosilica: Efficient Catalyst for Selective Hydrogenation & C_sp²−C_sp² Bond Formation Reactions

Abstract

Thiazoline functionalized periodic mesoporous organosilica (TPMO) supported palladium nanoparticles (Pd-TPMO) were fabricated through a co-condensation approach and successive incorporation of palladium nanoparticles using a doublesolvent technique. The TPMO and Pd-TPMO were characterized through 29 Si MAS NMR, FTIR, SAXS, XPS, FESEM, TEM and N 2 adsorption-desorption, which revealed the morphological and physicochemical properties of the materials. The catalytic performance of Pd-TPMO was evaluated for hydrogenation of industrially important compounds and C sp 2 À C sp 2 bond-formation reactions. The Pd-TPMO mediated catalytic reactions were found to be effective in producing the corresponding products with excellent yields and selectivity. The size and stability of palladium nanoparticles within the confined organosilica framework promotes excellent activity and recyclability of the catalyst without a significant loss in the yields for hydrogenation and C sp 2 À C sp 2 bond-formation reactions.[a] Dr.

Palladium Nanoparticles Supported on Porous Silica Materials as Heterogeneous Catalysts of C−C Coupling and Cross‐Coupling Reactions

“…Suresh and coworkers fabricated a catalyst by first producing a thiazoline-silyl precursor via reaction of 2-aminobenzonitrile with cysteamine hydrochloride, followed by treatment with (3-isocyanatopropyl)trimethoxysilane. [138] In subsequent steps, it was treated with TEOS, CTBA, and NH 4 F, to produce a thiazoline-bridged PMO support material as a white powder. Finally, deposition of palladium (Na 2 PdCl 4 , NaBH 4 , 2 h each, rt) provided the catalyst with a 0.64 wt% Pd loading and particles of 4-6 nm.…”

Recent advanced development of metal-loaded mesoporous organosilicas as catalytic nanoreactors

“…38) and Pd NPs inside the pore channel were stabilized by the functional group and pore connement effect. 199 Such a heterogeneous catalyst indicated an efficient catalytic activity in the selective hydrogenation of styrene oxide and styrene & C sp 2 -C sp 2 bond formation reactions for the synthesis of unsymmetrically substituted biaryl ketones and unsymmetrical biaryls as well as the cross-coupling reaction between aryl bromide and phenylboronic acids, while exhibiting high reusability. Moreover, except from that the aforementioned the difference of IL functional group from oragnosilica as the support inuenced Pd loading, Pd particle size and catalytic activity of catalyst, the inactive organic composite in the support also affected the immobilization of Pd NPs and the resulting catalytic activity.…”

“…38 Synthesis of the thiazoline-silyl precursor, thiazoline bridged periodic mesoporous organosilica (TPMO) and Pd NP entrapped TPMO (Pd-TPMO). 199 Reproduced with permission. 199 Copyright 2012, John Wiley & Sons.…”

“…In addition, for metal-loaded PMO heterogeneous catalysts, pore connement effects also strongly affect the activity of heterogeneous catalysts in organic synthesis. 106,134,162,168,199,208 Finally, it is necessary to emphasize that the hydrophobic microenvironment of PMOs also has an important inuence on the catalytic performance. For example, the Ti-PMO-catalyzed oxidation of 1-octene with TBHP indicated a remarkably different catalytic performance.…”

“…38 ) and Pd NPs inside the pore channel were stabilized by the functional group and pore confinement effect. 199 Such a heterogeneous catalyst indicated an efficient catalytic activity in the selective hydrogenation of styrene oxide and styrene & C sp 2 –C sp 2 bond formation reactions for the synthesis of unsymmetrically substituted biaryl ketones and unsymmetrical biaryls as well as the cross-coupling reaction between aryl bromide and phenylboronic acids, while exhibiting high reusability.…”