Immobilized Pd on a NHC functionalized metal–organic framework MIL‐101(Cr): an efficient heterogeneous catalyst in Suzuki−Miyaura coupling reaction in water

Abstract

A novel Pd−NHC functionalized metal–organic framework (MOF) based on MIL‐101(Cr) was synthesized and used as an efficient heterogeneous catalyst in the C‐C bond formation reactions. Using this heterogeneous Pd catalyst system, the Suzuki−Miyaura coupling reaction was accomplished well in water, and coupling products were obtained in good to excellent yields in short reaction time. The Pd−NHC−MIL‐101(Cr) was characterized using some different techniques, including Fourier transform‐infrared, X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy, inductively coupled plasma and elemental analysis. The microscopic techniques showed the discrete octahedron structure of MIL‐101(Cr), which is also stable after chemical modification process to prepare the catalyst system. The TEM images of the catalyst showed the existence of palladium nanoparticles immobilized in the structure of the catalyst, while no reducing agent was used. It seems that the NHC groups and imidazolium moieties in the structure of the MOF can reduce Pd (II) to Pd (0) species. This modified MOF substrate can also prevent aggregation of Pd nanoparticles, resulting in high stability of them in organic transformation. The Pd−NHC−MIL‐101(Cr) catalyst system could be simply extracted from the reaction mixture, providing an efficient synthetic method for the synthesis of biaryls derivatives using the aforementioned coupling reaction. The Pd−NHC−MIL‐101(Cr) catalyst could be recycled in this organic reaction with almost consistent catalytic efficiency.

Palladium nanoparticle supported on nitrogen‐doped porous carbon: Investigation of structural properties and catalytic activity on Suzuki–Miyaura reactions

“…[70][71][72][73][74][75][76][77][78][79] It shows that the APC-750@Pd catalyst has shown better catalytic activity than reported structurally similar catalysts in case of reaction conditions, catalyst concentration, and yields (Table 5). In the literature, [70][71][72][73][74][75][76][77][78][79] most of the Suzuki-Miyaura crosscoupling reactions catalyzed by similar types of catalysts require a high amount of catalyst loadings than our catalytic system. Although our catalytic system works well with aryl bromides, developed catalytic system does not have the same effect with 4-chloroacetophenone.…”

“…Fe@Pd/C H 2 O/K 2 CO 3 /80 C/0.5 mol% 60 90 Tang et al [70] Pd/C H 2 O/K 2 CO 3 /100 C/1.5 mol% 20 97 Rao et al [71] N-doped NPC-Pd EtOH-H 2 O/K 2 CO 3 /25 C/0.2 mol% 60 95 Zhang et al [72] N-doped PC-900-Pd EtOH-H 2 O/K 2 CO 3 /25 C/0.2 mol% 60 96 Zhang et al [73] MOF-5-NPC-900-Pd EtOH-H 2 O/K 2 CO 3 /25 C/0.1 mol% 45 96.3 Dong et al [74] PdNPs/CMK-3 EtOH-H 2 O/K 2 CO 3 /40 C/0.1 mmol% 30 96 Liu et al [75] Pd@mesoporous carbon H 2 O/K 2 CO 3 /100 C/10 μequiv. 600 97 Enneiymy et al [76] Pd@A-ZIF-8 EtOH-H 2 O/K 3 PO 4 /70 C/0.1 mol% 60 91 Dabiri et al [77] Pd-NHC-MIL-101(Cr) H 2 O/K 2 CO 3 /85 C/0.6 mol% 15 94 Niknam et al [78] Pd-loaded silica DMF/K 2 CO 3 /100 C 360 94 Sarkar et al [79] APC-750@Pd i-PrOH-H Reaction conditions: APC-750@Pd (5 mg, 0.049 mmol%Pd), phenylboronic acid (0.6 mmol), 4-bromoacetophenone (0.5 mmol), K 2 CO 3 (1.0 mmol), i-PrOH/H 2 O 3 mL (1:2). GC yields determine according to arylbormides using (trifluoromethyl)benzene as an internal standard.…”

“…In order to show the efficiency of the APC-750@Pd catalyst on the synthesis of biaryls, the activity of the APC-750@Pd catalyst was compared with heterogeneous palladium catalysts in Suzuki-Miyaura cross-coupling reactions. [70][71][72][73][74][75][76][77][78][79] It shows that the APC-750@Pd catalyst has shown better catalytic activity than reported structurally similar catalysts in case of reaction conditions, catalyst concentration, and yields (Table 5). In the literature, [70][71][72][73][74][75][76][77][78][79] most of the Suzuki-Miyaura crosscoupling reactions catalyzed by similar types of catalysts require a high amount of catalyst loadings than our catalytic system.…”

Low-Temperature and Additive-Free Synthesis of Spherical MIL-101(Cr) with Enhanced Dye Adsorption Performance

“…The terminal connected water molecules of MIL-101(Cr) can be removed under high temperature or vacuum conditions, which creates potential Lewis acid sites [20]. Hence, MIL-101(Cr) demonstrates quite good water stability, which makes it suitable for wide applications, especially in the presence of moisture/water conditions, such as catalysis [21,22], adsorption [23,24], separation [25,26], drug delivery [27,28], gas storage [29,30], water pollution treatment [31], and mixed matrix membranes [32,33], among others.…”

Synthesis of some new distyrylbenzene derivatives using immobilized Pd on an NHC-functionalized MIL-101(Cr) catalyst: photophysical property evaluation, DFT and TD-DFT calculations

“…In this work, in continuation of our program on the synthesis of stilbene derivatives, 45–50 a highly efficient heterogeneous catalyst system [Pd–NHC–MIL-101(Cr)] 51 was introduced to be applied in the synthesis of stilbene derivatives using Mizoroki–Heck coupling reaction. 52–57 The Pd–NHC–MIL-101(Cr) catalyst system showed remarkable catalytic activity in the Heck reaction 51 and in order to further show its utility in organic synthesis we investigate its applicability in the synthesis of distyrylbenzenes (DSBs). The synthetic pathway toward synthesis of [Pd–NHC–MIL-101(Cr)] catalyst system is shown in Scheme 1 .…”