A Graphene Oxide Nanosheet Supported NHC–Palladium Complex as a Highly Efficient and Recyclable Suzuki Coupling Catalyst

Abstract

A practical heterogeneous catalyst was prepared by anchoring a triazine-tethered N-heterocyclic carbene (NHC)–palladium complex on the surface of graphene oxide (GO) nanosheets. The immobilized complex was characterized by X-ray photoelectron spectroscopy, field-emission transmission electron microscopy, energy-dispersive X-ray spectroscopy, and surface area analysis. It proved to be a highly active and durable heterogeneous catalyst for Suzuki coupling reactions. At room temperature, the use of this catalyst enabled the preparation of various biaryls and heterobiaryls in short reaction times. The catalytic system could be recycled at least 10 times with almost consistent activity. The results reveal that the stable palladium complex is strongly anchored on the surface of GO nanosheets. Interestingly, an open planar network of the GO nanosheet support plays a role during the catalytic process in enhancing the catalytic activity.

Synthesis, characterization, and reactivity of a novel magnetically recyclable triazine‐based Cu–NNN–pincer complex

“…The specific surface area of Fe 3 O 4 and Fe 3 O 4 @SiO 2 –NH 2 MNPs was previously recorded as 77 and 138 m 2 /g, respectively. [ 72 ] The nitrogen adsorption/desorption isotherms and pore size distribution of Fe 3 O 4 @SiO 2 –NH–CCl–AT–Cu(II) were measured to check the porous nature and to estimate the surface area (Figure 7a). The BET, Langmuir surface area, and average pore volume ( p / p 0 = 0.990) of the Fe 3 O 4 @SiO 2 –NH–CCl–AT–Cu(II) were 28.422, 1086.1 m 2 /g, and 0.1162 cm 3 /g, respectively.…”

“…[69][70][71] 2.3 | Preparation of Fe 3 O 4 @SiO 2 -NH-CCl NPs Fe 3 O 4 @SiO 2 -NH 2 -CCl was prepared similarly to the reported procedure in the literature, with minor modification. [72] A mixture of Fe 3 O 4 @SiO 2 -NH 2 NPs (100 mg) in dry THF (30 ml) was sonicated at r.t. for 30 min. Then, cyanuric chloride (0.54 mmol, 100 mg) and triethylamine (0.6 mmol, 60 mg) were added to the mixture.…”

Design, Synthesis and Characterization of Aurone Based α,β‐unsaturated Carbonyl‐Amino Ligands and their Application in Microwave Assisted Suzuki, Heck and Buchwald Reactions

“…2‐phenylpyridine (5 l) : [45] Colourless Oil; Yield 88%; 1 H NMR (500 MHz, CDCl 3 ) δ 8.35 (d, J =6 Hz, 1H), 7.52 (t, J =9.6 Hz, 1H), 7.48–7.45 (m, 3H), 7.28–7.19 (m, 4H); 13 C NMR (125 MHz, CDCl 3 ) δ 150.27, 142.32, 138.46, 131.53, 130.06, 128.28, 126.90, 122.62, 122.51.…”

“…ethan-1-one (5 g): [39] [41] Yellow needle crystal; Yield: 54%; m. p 114-115 °C; 1 H NMR (400 MHz, CDCl 3 ) δ 8.02 (d, J = 7.9 Hz, 1H), 7.83 (d, J = 8.1 Hz, 1H), 7.48 (d, J = 7.9 Hz, 2H), 7.30-720 (m, 5H); 13 [42] White Solid; Yield 86%; m. p 61-62 °C; 1 H NMR (400 MHz, CDCl 3 ) 12.32 (s, 1H), 7.92 (s, 1H), 7.71 (d, J = 6.88 Hz, 1H), 7.55 (d, J = 6.04 Hz, 2H), 7.47 (t, J = 6.12 Hz, 2H), 7.37 (t, J = 5.76 Hz, 1H), 7.07 (d, J = 6.92 Hz, 1H), 2.69 (s, 3H); 13 [43] White Solid; Yield 81%; m. p 94-96 °C; 1 H NMR (400 MHz, CDCl 3 ) 7.77-7.74 (m, 2H), 7.50 (d, J = 6.12 Hz, 2H), 7.44 (t, J = 5.96 Hz, 2H), 7.36 (t, J = 5.88 Hz, 1H), 7.05 (d, J = 6.92 Hz, 1H), 3.97 (s, 3H); 13 10-phenylphenanthren-9-ol (5 k): [44] White Solid; Yield 91%; m. p 139-140 °C; [45] Colourless Oil; Yield 88%; 1 H NMR (500 MHz, CDCl 3 ) δ 8.35 (d, J = 6 Hz, 1H), 7.52 (t, J = 9.6 Hz, 1H), 7.48-7.45 (m, 3H), 7.28-7.19 (m, 4H); 13 C NMR (125 MHz, CDCl 3 ) δ 150. 27, 142.32, 138.46, 131.53, 130.06, 128.28, 126.90, 122.62, 122.51.…”

A Sustainable Approach for Graphene Oxide‐supported Metal N‐Heterocyclic Carbenes Catalysts

“…Qian et al demonstrated N-heterocyclic carbene (NHC)-of triazine type palladium complex on GO 5@GO to deliver better catalyst activities for Suzuki cross-coupling reactions with shorter reaction time along with good functional group tolerance (Scheme 13). [40] The stable heterogeneous catalyst 5@GO was strongly anchored on GO and remained active over ten cycles. Heterogeneous catalyst 5@GO synthesized by four steps synthetic procedure.…”