1591-30-6Relevant articles and documents
Conformationally controlled electron delocalization in n-type rods: Synthesis, structure, and optical, electrochemical, and spectroelectrochemical properties of dicyanocyclophanes
Vonlanthen, David,Rudnev, Alexander,Mishchenko, Artem,Kaeslin, Alexander,Rotzler, Juergen,Neuburger, Markus,Wandlowski, Thomas,Mayor, Marcel
, p. 7236 - 7250 (2011)
A series of dicyanobiphenylcyclophanes 1-6 with various π-backbone conformations and characteristic n-type semiconductor properties is presented. Their synthesis, optical, structural, electrochemical, spectroelectrochemical, and packing properties are investigated. The X-ray crystal structures of all n-type rods allow the systematic correlation of structural features with physical properties. In addition, the results are supported by quantum mechanical calculations based on density functional theory. A two-step reduction process is observed for all n-type rods, in which the first step is reversible. The potential gap between the reduction processes depends linearly on the cos2 value of the torsion angle ψ between the π-systems. Similarly, optical absorption spectroscopy shows that the vertical excitation energy of the conjugation band correlates with the cos2 value of the torsion angle ψ. These correlations demonstrate that the fixed intramolecular torsion angle ψ is the dominant factor determining the extent of electron delocalization in these model compounds, and that the angle ψ measured in the solid-state structure is a good proxy for the molecular conformation in solution. Spectroelectrochemical investigations demonstrate that conformational rigidity is maintained even in the radical anion form. In particular, the absorption bands corresponding to the SOMO-LUMO+i transitions are shifted bathochromically, whereas the absorption bands corresponding to the HOMO-SOMO transition are shifted hypsochromically with increasing torsion angle ψ. Copyright
Synthesis of 2-X-, 3-X-4,4′-Dicyanobiphenyls (X = CH3, OCH3, F) by Cross-Coupling of the Terephthalonitrile Dianion with Substituted Benzonitriles
Peshkov, Roman Yu.,Panteleeva, Elena V.,Shchegoleva, Lyudmila N.,Bagryanskaya, Irina Yu.,Rybalova, Tatyana V.,Vasilieva, Nadezhda V.,Shteingarts, Vitalij D.
, p. 4524 - 4531 (2015)
A concise noncatalytic synthetic approach to 2- and 3-substituted 4,4′-dicyanobiphenyls by applying terephthalonitrile dianion 12- as para-cyanophenylating reagent for neutral benzonitriles is described. Neutral participants are varied to reveal the scope of applicable substrates and to evaluate the electronic and structural factors governing the regioselectivity and efficiency of the cross-coupling. Benzonitriles substituted with Me, OMe and F provide the corresponding dicyanobiphenyls in good yields. The regularities in the reactivities are interpreted in terms of a reaction scheme involving the intermediacy of a charge-transfer complex between 12- and benzonitrile, which transforms into a dimeric dianion either through a heterolytic pathway and/or by successive single electron transfer and recombination of the primary generated radical anions. Quantum chemical calculations of the structure and energy of the principal reaction intermediates match the experimental data. CV measurements of the new dicyanobiphenyls are also included. Transition-metal-free biaryl cross-coupling utilises the terephthalonitrile dianion sodium salt for para-cyanophenylation of aromatic nitriles modified with methoxy, methyl, and fluorine substituents, with the formation of 2- and 3-substituted 4,4′-dicyanobiphenyls. The proposed reaction scheme is verified by quantum chemical calculations.
The homocoupling of arylsulfonylhydrazides by palladium-catalysed desulfonation in air
Zhang, Wei,Zhao, Baoli,Li, Ke
, p. 674 - 676 (2013)
A simple and efficient preparation of biaryl derivatives from arylsulfonyl hydrazides has been developed using Pd(OAc)2 as the catalyst in a mixed solvent of DMA and THF and without the use of any ligand and base.
Rapid gram-scale synthesis of Au/chitosan nanoparticles catalysts using solid mortar grinding
Reddy, K. Paul,Meerakrishna,Shanmugam,Satpati, Biswarup,Murugadoss
, p. 438 - 446 (2021)
Owing to the abundant functional groups present in the chitosan polymer, high density catalytic tiny gold particles with greater dispersion can be anchored on the chitosan powder using simple mortar and pestle. Chitosan-supported gold nanoparticles (NPs) with excellent control of size and shape were rapidly synthesized in gram-scale by solid-grinding without the need of any toxic solvents. The structure of catalysts and products was established by advanced instrumental and spectroscopic methods. The supported gold NPs functions as a heterogeneous catalyst for the homocoupling of phenylboronic acid and the aerobic oxidation of benzyl alcohol in water. The catalytic behaviour and activity of supported gold NPs was tuned/modulated by varying the ratio of chitosan polymer and gold precursor. Comparative studies showed that the solid chitosan supported gold catalyst exhibits superior catalytic activity and selectivity than the well known hydrophilic polymer-stabilized gold NPs catalysts prepared by the conventional solution-based methods.
Nickel catalyzed one pot synthesis of biaryls under air at room temperature
Bhat, Aparna P. I.,Inam, Fawad,Bhat, Badekai Ramachandra
, p. 22191 - 22198 (2013)
A practical, room temperature catalytic system has been developed for the synthesis of biaryls in one step from the homocoupling of in situ generated Grignard reagents using a nickel(ii) complex. The use of atmospheric oxygen as the oxidant makes the system environmentally friendly. The reaction system is compatible with diverse functionality to afford biaryls in appreciable yields. The Royal Society of Chemistry 2013.
Homocoupling of arylboronic acids catalyzed by simple gold salts
Matsuda, Takanori,Asai, Taro,Shiose, Shigeru,Kato, Kotaro
, p. 4779 - 4781 (2011)
A range of arylboronic acids undergo a homocoupling reaction in the presence of catalytic amount of gold salts to yield symmetrical biaryls. Alkenylboronic acids, arylboronic esters, and arylborates also participate in the gold-catalyzed homocoupling reaction.
Efficient and durable Au alloyed Pd single-atom catalyst for the Ullmann reaction of aryl chlorides in water
Zhang, Leilei,Wang, Aiqin,Miller, Jeffrey T.,Liu, Xiaoyan,Yang, Xiaofeng,Wang, Wentao,Li, Lin,Huang, Yanqiang,Mou, Chung-Yuan,Zhang, Tao
, p. 1546 - 1553 (2014)
Ion exchange resin supported Au alloyed Pd single atoms have been explored to serve as an effective and robust catalyst for the Ullmann reaction of aryl halides under mild conditions in aqueous media, in particular for the activation of less reactive aryl chlorides. The catalysts were prepared with an ion exchange-NaBH4 reduction method and submitted to extensive characterizations by HRTEM, XRD, EXAFS, and DRIFTS techniques. XRD patterns demonstrated the formation of Au-Pd alloys. EXAFS and DRIFTS characterization results showed that with an increase of Au/Pd molar ratios, the continuous Pd ensembles on the surface were gradually separated and eventually isolated by Au atoms, confirming that the Au alloyed Pd single-atom catalyst was formed. The catalysts exhibited excellent performance for the Ullmann reaction of aryl chlorides, and the turnover number (TON) increased exponentially with a decrease of the amount of Pd in the catalysts. On the basis of these characterization and catalytic results, the Au alloyed Pd single-atom was proposed as the active site for the reaction. The catalyst exhibited excellent catalytic performance for a broad scope of substrates and could be reused at least 8 times with no change in yield. This Au alloyed Pd single-atom catalyst bridges the gap between homogeneous and heterogeneous catalysis in organic transformations and may open a new vision to develop other efficient single-atom catalysts for green synthesis of fine chemicals.
Ullmann homocoupling of aryl iodides catalyzed by gold nanoparticles stabilized on magnetic mesoporous silica
Rostamizadeh, Shahnaz,Estiri, Hamid,Azad, Mohammad
, p. 1005 - 1010 (2017)
Abstract: We demonstrated a convenient new procedure of the Ullmann homocoupling reaction for the synthesis of symmetrical biaryls via homocoupling of aryl iodides over a recyclable gold catalyst comprising Au nanoparticles supported on functional magnetic mesoporous silica (α-Fe2O3)-MCM-41-HS-Au. The catalyst was easily separated by an external magnet, and the recovered catalyst was reused in six successive reaction cycles without any significant loss of activity. So, using this catalyst is affordable. Also, the reaction time is much shorter than a few previously reported work. Graphical Abstract: [Figure not available: see fulltext.]
Facile synthesis of symmetrical functionalized biaryls from aryl halides catalyzed by commercial zinc dust using ammonium formate
Abiraj,Srinivasa,Channe Gowda
, p. 2081 - 2084 (2004)
Reductive homocoupling of aryl halides in the presence of commercial zinc dust and ammonium formate in methanol produces biaryls in good to excellent yields. Aryl halides having either electron-donating or electron-withdrawing groups underwent smooth coupling to afford the corresponding symmetrical biaryls. Addition of 1equiv of sodium hydroxide enhanced the coupling reaction rate. Commercial zinc dust is inexpensive, widely available and can be used without any auxiliary catalysts such as Pd(0) and/or Ni(0).
Pd-catalyzed homocoupling of arylhydrazines via C - N cleavage under O 2
Yao, Peng
, p. 194 - 197 (2014)
An efficient and simple synthetic method for biaryl synthesis was developed using Pd(OAc)2 as catalyst from aryl hydrazides under O2. Various biaryls were synthesized in good yields, offering an expedient protocol for the synthesis of symmetrical biaryl molecules via C - N cleavage. The reactions were performed in component solvent of toluene and acetone without using any pro-oxidant. Copyright
One-step synthesis of biaryls under mild conditions
Bhat, Aparna P. I.,Inam, Fawad,Bhat, Badekai Ramachandra
, p. 7139 - 7144 (2013)
A one-step synthesis of symmetrical biaryls was developed and uses a nickel(III) complex containing a Schiff base and dithiolate ligands as a catalyst for the homocoupling of in situ generated Grignard reagents. The coupling reaction was performed at room temperature with molecular oxygen as the oxidant, which renders the reaction energy-efficient and environmentally friendly. The catalytic methodology is compatible with diverse functionalities, including chlorido, nitro, nitrile, and heteroatoms, and provides biaryls in appreciable yields. A practical, room-temperature nickel(III) catalytic system has been developed for the synthesis of biaryls in one step from the homocoupling of in situ generated Grignard reagents. The use of molecular oxygen as the oxidant makes the system environmentally friendly. The reaction system is compatible with diverse functionalities and affords biaryls in appreciable yields. Copyright
Gold/palladium bimetallic alloy nanoclusters stabilized by chitosan as highly efficient and selective catalysts for homocoupling of arylboronic acid
Sophiphun, Onsulang,Wittayakun, Jatuporn,Dhital, Raghu Nath,Haesuwannakij, Setsiri,Sakurai, Hidehiro,Murugadoss, Arumugam
, p. 1238 - 1243,6 (2012)
Aerobic oxidative homocoupling of arylboronic acid under acidic aqueous conditions (pH 4.0) using bimetallic Au/Pd alloy nanoclusters stabilized by chitosan has been investigated. It was found that a Au0.81Pd 0.19 catalyst (3.1±0.8nm) exhibited superior catalytic activities as compared to monometallic Au (2.30.3nm) and other series of bimetallic nanoclusters, giving the corresponding biaryls in nearly quantitative yield.
Shikata et al.
, p. 3274 (1970)
Diquat derivatives, a precursor of organic reductant
Kuroboshi, Manabu,Kondo, Takashi,Tanaka, Hideo
, p. 723 - 729 (2015)
Electroreduction of diquat triflate gave a potent organic reductant, which promoted reductive dimerization of aryl bromides in the presence of palladium catalysts to give the corresponding biaryl compounds.
Nickel- and Palladium-Catalyzed Cross-Coupling of Stibines with Organic Halides: Site-Selective Sequential Reactions with Polyhalogenated Arenes
Ghaderi, Arash,Kambe, Nobuaki,Le, Liyuan,Lu, Hao,Qiu, Renhua,Tang, Ting,Tong, Zhou,Wong, Wai-Yeung,Xu, Zhi,Yin, Shuang-Feng,Zeng, Dishu,Zhang, Dejiang,Zhang, Zhao
, p. 854 - 867 (2022/01/19)
Herein, we disclose a general and efficient method for the synthesis of Sb-aryl and Sb-alkyl stibines by the nickel-catalyzed cross-coupling of halostibines with organic halides. The synthesized Sb-aryl stibines couple with aryl halides to give biaryls efficiently via palladium catalysis. Sequential reactions of stibines with polyhalogenated arenes bearing active C–I/C–Br sites and inactive C–Cl sites successfully proceeded, resulting in the formation of a variety of complex molecules with good site selectivity. Drugs such as diflunisal and fenbufen, as well as a fenofibrate derivative, were synthesized on gram scales in good yields, together with the high recovery of chlorostibine. Furthermore, catalytic mechanisms are proposed based on the results of control experiments.
Reductive Coupling of Aryl Halides via C—H Activation of Indene
Zhang, Bo-Sheng,Yang, Ying-Hui,Wang, Fan,Gou, Xue-Ya,Wang, Xi-Cun,Liang, Yong-Min,Li, Yuke,Quan, Zheng-Jun
, p. 1573 - 1579 (2021/05/28)
This paper describes the first case of a reductive coupling reaction with indene, a non-heteroatom olefin used as a reducing agent. The scope of the substrate is wide. The homo-coupling, cross-coupling, and synthesis of 12 and 14-membered rings were realized. The control experiment, indene-product curve and density functional theory calculations showed that the η3-palladium indene intermediate was formed by C—H activation in the presence of cesium carbonate. We speculate that the final product was obtained through a Pd (IV) intermediate or aryl ligand exchange. In addition, we excluded the formation of palladium anion (Pd(0)?) intermediates.
