604-53-5Relevant articles and documents
Dynamics of Atropisomerization of 1,1'-Binaphtyl in Several Nematic Solvents. Rate Enhancement by a Solid Phase
Naciri, Jaouad,Spada, Gian Pierro,Gottarelli, Giovanni,Weiss, Richard G.
, p. 4352 - 4357 (1987)
The rates of atropisomerization of (S)-1,1'-binaphtyl (BN) are compared in six nematic phases and in the solid phase of p-methoxybenzylidene-p-n-butylaniline.The influence of each phase on the activation parameters for atropisomerization are correlated with the solvent molecular structures.The results in the nematic and solid phases are interpreted in terms of degree to which the solvent matrices flatten the angle between the naphtyl rings of BN.
-
Smith
, (1877)
-
Origin of the excellent catalytic activity of Pd loaded on ultra-stable y zeolites in Suzuki-Miyaura reactions
Okumura, Kazu,Tomiyama, Takuya,Okuda, Shizuyo,Yoshida, Hiroyuki,Niwa, Miki
, p. 156 - 166 (2010)
Suzuki-Miyaura reactions were performed over Pd loaded on (ultra-stable Y) USY zeolites prepared by steam treatment of NH4-Y. We found that the catalytic activity of Pd increased significantly with steam treatment of NH 4-Y when 6% H2 was applied before and during the reactions. For instance, a TON of 13,000,000 was obtained in the reaction between bromobenzene and phenylboronic acid in 1.5 h. Pd K-edge and Pd L 3-edge X-ray absorption fine structure analyses revealed the formation of atomic Pd with a cationic character. The catalytic activity of Pd/USY prepared under different steam-treatment conditions was in good correlation with the strong Bronsted acid sites induced by the extra-framework Al. Based on the catalytic performance data, the structure of Pd, and acidic analysis of the support, atomic Pd anchored to the strong Bronsted acid sites of the USY zeolite was proposed to be the active species.
Structures and photoluminescence of Silver(I) and Gold(I) cyclic trinuclear complexes with aryl substituted pyrazolates
Saotome, Mai,Shimizu, Daichi,Itagaki, Ayaka,Young, David James,Fujisawa, Kiyoshi
, p. 533 - 536 (2019)
The 4-aryl substituted pyrazolate ligands, L1(Ph)H and L1(Naph)H, were synthesized by SuzukiMiyaura cross-coupling and combined with metal sources to give cyclic trinuclear structures [AgL1(Ph)]3, [AuL1(Ph)] 3, [AgL1(Naph)] 3, and [AuL1(Naph)]3. The aryl group determined the crystal packing of these cyclic trinuclear complexes with the phenyl systems exhibiting stair type solid state structures and the naphthyl complexes exhibiting irregular structures with spaces occupied with some solvent molecules. These differences in solid-state structures were accompanied by differences in MN stretching frequencies and temperature dependent photoluminescence.
Deracemization of a Racemic Compound by Using Tailor-Made Additives
Engwerda, Anthonius H. J.,van Schayik, Pim,Jagtenberg, Henjo,Meekes, Hugo,Rutjes, Floris P. J. T.,Vlieg, Elias
, p. 2863 - 2867 (2018)
Viedma ripening is a process that combines abrasive grinding of a slurry of crystals with solution-phase racemization, resulting in solid-phase deracemization. One of the major disadvantages of Viedma ripening is that the desired compound needs to crystallize as a racemic conglomerate, accounting for only 5–10 % of all chiral molecules. Herein, we show that use of a chiral additive causes deracemization under conditions, in which the compound normally crystallizes as a racemic compound. Although this concerns a single example, it is envisioned that through this new approach the scope of Viedma ripening can be significantly expanded.
Suzuki homo-coupling reaction based fluorescent sensors for monosaccharides
Xu, Su-Ying,Wang, Hui-Chen,Flower, Stephen E.,Fossey, John S.,Jiang, Yun-Bao,James, Tony D.
, p. 35238 - 35241 (2014)
Palladium catalysed, aryl boronic acid homocoupling, is explored as a fluorescence sensing regime for saccharides. The catalytic formation rate of fluorescent bi-aryls, under control of a palladium catalyst, is modulated by the presence of saccharides. The nature of the aryl group, rate of biaryl formation and limits of detection are investigated.
Bimetallic Ni–Pd Synergism—Mixed Metal Catalysis of the Mizoroki-Heck Reaction and the Suzuki–Miyaura Coupling of Aryl Bromides
Kashid, Abhijit A.,Patil, Dharmaraj J.,Mali, Ramling D.,Patil, Vijay P.,Neethu,Meroliya, Heena K.,Waghmode, Shobha A.,Iyer, Suresh
, p. 353 - 358 (2020/08/05)
Abstract: A combination of Pd and Ni complexes activated aryl bromides for the thermal Mizoroki-Heck reaction and Suzuki coupling giving high yields in short reaction times. A thermal redox mechanism probably occurs whereby Ni complex transfers electron and reduces the Pd (II) to Pd (0) which then takes the reactants through the standard protocol of oxidative-addition, migratory insertion and reductive elimination, typical for the Mizoroki-Heck reaction and the Suzuki coupling. Graphic Abstract: [Figure not available: see fulltext.]
Tandem Mn–I Exchange and Homocoupling Processes Mediated by a Synergistically Operative Lithium Manganate
Uzelac, Marina,Mastropierro, Pasquale,de Tullio, Marco,Borilovic, Ivana,Tarrés, Màrius,Kennedy, Alan R.,Aromí, Guillem,Hevia, Eva
supporting information, p. 3247 - 3253 (2020/12/11)
Pairing lithium and manganese(II) to form lithium manganate [Li2Mn(CH2SiMe3)4] enables the efficient direct Mn–I exchange of aryliodides, affording transient (aryl)lithium manganate intermediates which in turn undergo spontaneous C?C homocoupling at room temperature to furnish symmetrical (bis)aryls in good yields under mild reaction conditions. The combination of EPR with X-ray crystallographic studies has revealed the mixed Li/Mn constitution of the organometallic intermediates involved in these reactions, including the homocoupling step which had previously been thought to occur via a single-metal Mn aryl species. These studies show Li and Mn working together in a synergistic manner to facilitate both the Mn–I exchange and the C?C bond-forming steps. Both steps are carefully synchronized, with the concomitant generation of the alkyliodide ICH2SiMe3 during the Mn–I exchange being essential to the aryl homocoupling process, wherein it serves as an in situ generated oxidant.
Sterically enhanced 2-iminopyridylpalladium chlorides as recyclable ppm-palladium catalyst for Suzuki–Miyaura coupling in aqueous solution
Liang, Tongling,Lin, Wenhua,Ma, Yanping,Sun, Wen-Hua,Zhang, Liping
, (2021/10/20)
Sterically hindered 2-iminopyridine derivatives and their palladium chlorides complexes are designed and prepared, which efficiently promote the Suzuki–Miyaura coupling (SMC) reaction in aqueous solution. Besides the good to excellent yields and broad substrate scope, these catalysts can be reused for at least four new batches of the substrates. Spontaneous separation of coupling products in the aqueous reaction medium is the additional striking feature of this catalytic process. Furthermore, catalytic performance of palladium complexes bearing the azo-bridged phenyl groups was greatly influenced by the UV irradiation due to the cis/trans photoisomerization of azo unit of the catalysts. In conclusion, titled palladium complexes provide a green, sustainable, cost-effective, and convenient process to synthesize SMC products at multi-gram-scale reaction.
