Solvent-Resistant Nanofiltration of Enlarged (NHC)Pd(allyl)Cl Complexes for Cross-Coupling Reactions

Abstract

An enlarged imidazolinium salt with a molecular mass of nearly 800 g/mol was synthesized and the respective N-heterocyclic carbene (NHC= N,N′-bis(2,6-diisopropyl-4-CH2NCy2-phenyl)-4,5-dihydroimidazol-2-ylidene) converted into (NHC)Pd(allyl)Cl and (NHC)Pd(cinnamyl)Cl complexes. The cinnamyl complex displays excellent activities in the Suzuki−Miyaura coupling and the Buchwald−Hartwig amination. The separation of this complex from the coupling products by means of a solvent-resistant nanofiltration using a PDMS (polydimethylsiloxane) membrane on PAN (polyacrylonitrile) was tested, and very high retention of between 97% and 99.9% of the (NHC)Pd complex was observed. The residual Pd content in the cross-coupling products is in the range 3.5−25 ppm.

Recent Advances in Polymeric Solvent‐Resistant Nanofiltration Membranes

“…124,[161][162][163][164] Most recently, the separation and purification of active molecules in organic medium by NF membranes (called SRNF membranes) has attracted significant attention because unlike conventional distillation, this process is athermal. The SRNF membranes can potentially be used in the pharmaceutical manufacturing industry, [165][166][167][168][169][170][171][172][198][199][200] catalysis recovery processes, [173][174][175][176][177][178][179][180][181][182][183]196,197 the concentration of biologically active compounds in food technology, 192 the recovery of ion liquids, [184][185][186] the purification of fuels and solvents, 188,189 refining technologies, 187 and many other fields. 205 All of these fields have a common feature: the cost and the energy consumption to prepare or recover active molecules are very high, which makes the application of SRNF economically attractive.…”

“…173,174 Compared with the recovery of phase transfer catalysts, SRNF should be more suitable to recover homogeneous catalysts, especially transition metal catalysts. [175][176][177][178][179][180][181][182][183] Schoeps et al 178 developed a type of PDMS SRNF membrane on a PAN porous support and thermally cross-linked the membranes. This type of thermal cross-linked PDMS/PAN SRNF membrane performed well in Suzuki-Miyaura coupling and Buchwald-Hartwig amination for separating (NHC)Pd(allyl)Cl and (NHC)Pd(cinnamyl)Cl complexes from the coupling compounds (shown in Fig.…”

Design of membrane cascades according to the method of McCabe-Thiele: An organic solvent nanofiltration case study for olefin hydroformylation in toluene

“…Organic Solvent Nanofiltration (OSN) is a recent separation process with many possible applications in fine chemistry especially for the recycling of homogeneous catalysts [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], in the pharmaceutical industry [20,21], in petro chemistry [22,23] and in biotechnologies [24].…”

Dinuclear (η3‐Allyl)palladium Complexes Bridged by a Chelating Phosphine Ligand: Synthesis and Catalytic Application to Suzuki–Miyaura CC Coupling Reactions

“…The dinuclear (η 3 -allyl) complexes appeared to be efficient catalysts for the Pd-catalyzed Suzuki-Miyaura C C coupling reactions of aryl bromides and phenyl boronic acid, but showed poor catalytic activity toward aryl chlorides. (7), Pd1-C15 2.182(4), Pd1-P1 2.3026(9); C15A-Pd1-C15 67.5(2), C15A-Pd1-P1 162.9(1), P1-Pd1-P1A 101.72 (5). and AgBF 4 (0.076 g, 0.39 mmol) in the ice bath was added CH 2 Cl 2 (13 cm 3 ).…”