4906-22-3Relevant articles and documents
Catalytic applications of CuII-containing MOFs based on N-heterocyclic ligand in the oxidative coupling of 2,6-dimethylphenol
Xiao, Bo,Hou, Hongwei,Fan, Yaoting
, p. 2014 - 2020 (2007)
Two CuII complexes bearing a N-heterocyclic ligand, namely [Cu(SO4)(pbbm)]n (1) and {[Cu(Ac)2(pbbm)] · CH3OH}n (2) (pbbm = 1,1′-(1,5-pentanediyl)bis-1H-benzimidazole) have been synthesized with the aim of exploiting new and potent catalysts. Single crystal X-ray diffraction shows that new polymeric complex 1 features 1-D double-chain framework. The catalytic studies on 1 and 2 indicate that they are efficient homogeneous catalysts for the oxidative coupling of 2,6-dimethylphenol (DMP) to poly(1,4-phenylene ether) (PPE) and diphenoquinone (DPQ) with H2O2 as oxidant and NaOMe as co-catalyst at room temperature. Optimal reaction conditions are obtained by examining the effects of solvent, the reaction time, temperature as well as the amounts of co-catalyst, catalyst and oxidant. Under the optimal conditions, the selectivity to PPE is almost up to 90% for both complexes, and the conversion of DMP is 85% for 1 and 90% for 2, comparable to those observed for highly active catalyst systems in the literature. Further comparison of their catalytic performances with those of the corresponding copper salt together with organic ligand, copper salt alone and free ligand reveals that the coordination of ligand to CuII ion plays a key role in generating the superior reactivities of complexes.
Tsuruya et al.
, p. 254 (1977)
Preparation and Catalytic Oxidizing Potential of Polymer Supported Chelating Amine and Schiff Base Complexes
Drago, Russell S.,Gaul, John,Zombeck, Alan,Straub, Darel K.
, p. 1033 - 1038 (1980)
A new, versatile, high-yield synthesis for covalently attaching multidentate chelates to polystyrene is described.Polymeric substrates containing bound polydentate amines as discrete units can be obtained by reacting chloromethylated polystyrene with bis(2-cyanoethyl)amine, followed by BH3/THF reduction, to provide polymer-attached bis(3-aminopropyl)amine, (*)-DPT.These materials form the basis for the preparation of a wide variety of chelating ligands, for example, through the Schiff base reaction with various aldehydes and ketones.In order to demonstrate the feasibility of these polymer reactions, the entire sequence of reactions was carried out in solution using benzyl chloride as the starting material.A series of polymer-bound metal complexes were prepared and characterized.ESR spectra of the polymer-bound CuIISalDPT and CoIISalDPT*O2 complexes were very similar to their respective frozen glass spectra.The Moessbauer spectrum of the polymer-bound FeIISalDPT was similar to the powder spectrum.The Fe(II)-bound complex was irreversibly oxidized upon exposure to air.The CoIISalDPT-bound complex was found to be an active catalyst for the oxidation of 2,6-dimethylphenol.A large enhancement in product selectivity is obtained with the polymer Co(II) complex over the solution analogue.
Horswill,Ingold
, p. 263,265 (1966)
Hydrothermal syntheses of metal-organic frameworks constructed from aromatic polycarboxylate and 4,4′-bis(1,2,4-triazol-1-ylmethyl)biphenyl
Mu, Yajuan,Fu, Junhong,Song, Yajing,Li, Zhen,Hou, Hongwei,Fan, Yaoting
, p. 2183 - 2193 (2011)
Six new metal-organic frameworks, namely, {[Co(btmb)(HBTC)]?2H 2O}n (1), {[Co3(btmb)3(BTC) 2(H2O)2]?6H2O}n (2), {[Co3(btmb)3(BTC)2(H2O) 4]?2H2O}n (3), {[Ni3(btmb) 3(BTC)2(H2O)4]?2H 2O}n (4), [Cu(btmb)(HBTC)]n (5), and [Cu(btmb)(NDC)]n (6) (H3BTC = 1,3,5-benzenetricarboxylic acid, H2NDC = 1,2-benzenedicarboxylic acid, and btmb = 4,4′-bis(1,2,4-triazol-1-ylmethyl)biphenyl), have been synthesized under hydrothermal conditions. The structure of 1 is a 6-connected self-penetrating three-dimensional (3D) framework with 44?610?8 topology. Complex 2 exhibits a trinodal (3,4)-connected topology with a Schlaefli symbol of (62?84)(64? 82)(63). Both complexes 3 and 4 possess 3D pillar-layered structures with a Schlaefli symbol of (62?8?10 3)(64?8?10)(6?102). Complex 5 is also a 3D polymer with a pillar-layered framework, which can be simplified as the (63)(69?8) topology. Complex 6 shows a 4-connected 3D framework with a Schlaefli notation of (65?8) 2. Furthermore, complexes 1-6 as heterogeneous catalysts were studied in the green catalysis process of the oxidative coupling of 2,6-dimethylphenol (DMP) to poly(1,4-phenylene ether) (PPE) and diphenoquinone (DPQ). The results show that these complexes exhibit different catalytic activities; both the Cu complexes are catalytically active by showing high conversion of DMP and high selectivity of PPE, and they exhibit great potential as recyclable catalysts.
Depolymerization of poly(2,6-dimethyl-1,4-phenylene oxide) under oxidative conditions
Saito, Kei,Masuyama, Toru,Oyaizu, Kenichi,Nishide, Hiroyuki
, p. 4240 - 4246 (2003)
Depolymerization of an engineering plastic, poly(2,6-dimethyl-1, 4-phenylene oxide) (PPO), was accomplished by using 2,6-dimethylphenol (DMP) under oxidative conditions. The addition of an excess amount of DMP to a solution of PPO in the presence of a CuCl/pyridine catalyst yielded oligomeric products. When PPO (Mn = 1.0 × 104, M w/Mn = 1.2) was allowed to react with a sufficient amount of DMP, the molecular weight of the product decreased to Mn = 4.9 × 102 (Mw/Mn = 1.5). By a prolonged reaction with the oxidant, the oligomeric product was repolymerized to produce PPO essentially identical to the starting material, making the oligomer useful as a reusable resource. During the depolymerization reaction, an intermediate phenoxyl radical was observed by ESR spectroscopy. Kinetic analysis showed that the rate of the oxidation of PPO was about 10 times higher than that of DMP. These results show that a monomeric phenoxyl radical attacks the polymeric phenoxyl to induce the redistribution via a quinone ketal intermediate, leading to the substantial decrease in the molecular weight of PPO, which is much faster than the chain growth.
Carboxylic-supported copper complexes as catalyst for the green oxidative coupling of 2,6-dimethylphenol: Synthesis, characterization and structure
Liu, Qi,Wu, Huai Guang
, p. 451 - 461 (2013)
Three new Cu(II) complexes with carboxylic ligand, namely {[Cu(qc) 2(py)]·4H2O}∞ (1), [Cu(qc) 2(4,4′-bpy)]∞ (2) and [Cu(pc)(2,2′-bpy) (H2O)]2·H2O (3) (Hqc = 3-hydroxy-2-quinoxalinecarboxylic acid, H2pc = 4-hydroxyphthalic acid, py = pyrazine) have been synthesized and characterized. In both 1 and 2, each Cu(II) ion is coordinated by two quinoxalinecarboxylate moieties in the equatorial plane and two 4,4′-bpy or pyrazine units provide coordination in the axial positions, thus, resulting in a 1-D polymeric chain structure. Complex 3 has a dimeric structure in which two Cu(II) cations are bridged by two deprotonated pc2- ligands and two 2,2′-bpy molecules. As heterogeneous catalysts, the title complexes showed high catalytic efficiency in the green oxidative polymerization of 2,6-dimethylphenol (DMP) to poly(1,4-phenylene ether) (PPE) in the presence of H2O2 as oxidant in water under mild conditions. Moreover, they allow reuse without significant loss of activity through four runs, which suggests that these catalysts are efficient, mild, and easily recyclable for the oxidative coupling of DMP. The preliminary study of the catalytic-structural correlations suggests that the coordination environment of the metal center plays an important role in the improvement of their catalytic efficiencies.
Method for synthesizing and preparing 3,3',5,5'-tetraalkyl-4,4'-biphenyl quinone
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Paragraph 0050-0051; 0061-0063; 0072, (2020/02/27)
The invention relates to a method for synthesizing and preparing 3,3',5,5'-tetraalkyl-4,4'-biphenyl quinone. According to the method, a novel bis(2-hydroxyloxo-1,10-o-phenanthroline minus monovalent anion)binuclear cuprous (I) complex is added into a synthesis reaction system, and the 3,3',5,5'-tetraalkyl-4,4'-biphenyl quinone is synthesized and prepared from 2,6-dialkyl phenol in a high-selectivity manner under the conditions that a temperature is relatively low, the reaction time is relatively short, a reaction solvent is economical and air serves as an oxidant.
Selective, Catalytic, and Metal-Free Coupling of Electron-Rich Phenols and Anilides Using Molecular Oxygen as Terminal Oxidant
Bering, Luis,Vogt, Melina,Paulussen, Felix M.,Antonchick, Andrey P.
supporting information, p. 4077 - 4080 (2018/07/15)
Selective oxidative homo- and cross-coupling of electron-rich phenols and anilides was developed using nitrosonium tetrafluoroborate as a catalyst. Oxidative coupling of phenols revealed unusual selectivities, which translated into the unprecedented synthesis of inverse Pummerer-type ketones. Mechanistic studies suggest that oxidative coupling of phenols and anilides shares a common pathway via homolytical heteroatom-hydrogen bond cleavage. Nitrosonium salt catalysis was applied for cross-dehydrogenative coupling initiated by generation of heteroatom-centered radicals.
