Palladium complexes bearing an N‐heterocyclic carbene–sulfonamide ligand for cooligomerization of ethylene and polar monomers

Abstract

This manuscript is dedicated to Professor Mitsuo Sawamoto's outstanding achievements in polymer chemistry and recognizes his recent retirement from 40 years of exceptional service to Kyoto University.ABSTRACT: Herein, we report the synthesis of palladium complexes bearing an N-heterocyclic carbene (NHC)-sulfonamide bidentate ligand and their application in ethylene oligomerization and ethylene/polar monomer cooligomerization. These catalysts could smoothly catalyze ethylene oligomerization and ethylene/methyl acrylate cooligomerization albeit the performance was lower compared to that of a NHC-phenoxide catalyst.

Novel and efficient bridged bis(N‐heterocyclic carbene)palladium(II) catalysts for selective carbonylative Suzuki–Miyaura coupling reactions to biaryl ketones and biaryl diketones

“…The spectral data of the ketones were the same as reported in the literature (SI-A and SI-B). [2,[33][34][35][36][37][38]46,47] 3 | RESULTS AND DISCUSSIONS…”

“…[7,20,[22][23][24][25][26][27][28][29][30][31] For the past two decades, serious effort has been put into the development of N-heterocyclic carbene (NHC) metal complexes and a revolution has been achieved, especially in their applications as organometallic catalysts. [32][33][34][35][36][37][38] This has been attributed to the ability of NHC ligands to donate σ electrons, which leads to the formation of strong and stable bonds with the metals and prevents formation of inactive palladium black in the catalytic cyclic. [34,39,40] These ligands are also attractive due to the possibility of modifying their structures; their steric and electronic properties can be adjusted to be appropriate for targeted applications in catalysis'.…”

Synthesis of 6,13-dihydro-6,13-ethanopentacene-15,16-diimine palladium(II) complex and steric effect of the backbone polycyclic aromatic system on palladium-catalyzed olefin polymerization

“…The 13 C NMR spectra of poly(NB-co-1-octene) containing 19.5% of 1-octene obtained by using the C2/B(C 6 F 5 ) 3 system are shown in Figure 2. The resonances of the methyl C8′ and methylene C7′ carbons of the hexyl branch and the methine carbons 1/2 and the 3/6 carbons of the 2,3-inserted NB unit are observed at 14, 23, 46-48, and 48-55 ppm together with those of the other carbons around 26.0-46.0 ppm, indicating the production of poly(NB-co-1-octene) with all the catalytic systems.…”

“…Since Brookhart and colleagues discovered aryl-substituted α-diimine nickel and palladium complexes for olefin polymerization, [1][2][3] late-transition-metal catalysts have attracted increasing attention due to their lower oxophilicity and resistance toward polar functionalit ies. [4][5][6][7][8][9][10][11][12][13] A series of breakthroughs have been made in this field, mainly involving other late transition metal αdiimine catalysts.…”

Robust alkyl‐bridged bis(N‐heterocyclic carbene)palladium(II) complexes anchored on Merrifield's resin as active catalysts for the selective synthesis of flavones and alkynones

“…(NHC)palladium(II) complexes were used efficiently in different applications including carbonylative coupling and alkoxycarbonylation and aminocarbonylation reactions. [ 36–40 ] The activity of (NHC)palladium(II) complexes is connected to the bonding nature of the NHC ligands including a strong σ‐electron donation, as well as a significant π acidity and π basicity, contributing to the stability of the different intermediates of the catalytic cycle and preventing deactivation pathways such as the formation of inactive palladium black. [ 41,42 ] The stability of these complexes can be further enhanced by the thermodynamic chelate effect such as the case of the chelating bis(NHCs).…”