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
Viologen as catalytic organic reductant: Electro-reductive dimerization of aryl bromides in a Pd/viologen double mediatory system
Kuroboshi, Manabu,Shiba, Takuya,Tanaka, Hideo
, p. 3666 - 3668 (2013)
Viologen can be used as an in situ recyclable organic reductant. Pd-catalyzed electrochemical reductive coupling of aryl bromides was performed by using a catalytic amount of viologen to afford the corresponding biaryls in good to moderate yields.
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.
Oxidative homocoupling of arylboronic acids catalyzed by a 4-aminoantipyrine-Pd(II)complex
Contreras-Celedón, Claudia Araceli,Rincón-Medina, José Arturo,Mendoza-Rayo, Darío,Chacón-García, Luis
, p. 439 - 442 (2015)
A one-step synthesis of symmetric biaryls is reported under very mild conditions via the homocoupling reaction of substituted arylboronic acids using an air- and moisture-stable 4-aminoantipyrine-Pd(II) complex as catalyst. The reaction is conducted at a low catalyst loading of 0.1 mol% at room temperature in methanol in the presence of K2CO3 as the base and KMnO4 as the oxidant. The catalytic methodology is shown to be compatible with diverse functional groups and affords the desired biphenyls in good to excellent yields.
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.
Catalytic properties of Au and Pd nanoparticles decorated on Cu 2O microcubes for aerobic benzyl alcohol oxidation and Suzuki-Miyaura coupling reactions in water
Prasad, K. Sudhakara,Noh, Hui-Bog,Reddy, S. Subba,Reddy, A. Eswar,Shim, Yoon-Bo
, p. 72 - 77 (2014)
The catalytic activities of Cu2O microcubes decorated with Au and Pd nanoparticles (Cu2O/Au and Cu2O/Pd) were synthesized by a microwave assisted technique and examined for the specific organic reactions, separately. Cu2O/Au and Cu2O/Pd catalysts were characterized and examined as the catalysts for the aerobic oxidation of benzyl alcohol to benzaldehyde and the Suzuki-Miyaura coupling reaction in water, separately. The yields of products were >90% with a selectivity of >99% for both catalytic reactions. The cheap, ligand free, efficient, non-toxic, and water soluble properties make the present catalyst ultimate for Suzuki and aerobic oxidation reaction.
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.
Palladium nanoparticles immobilized on the magnetic few layer graphene support as a highly efficient catalyst for ligand free Suzuki cross coupling and homo coupling reactions
Rafiee, Fatemeh,Khavari, Parvaneh,Payami, Zahra,Ansari, Narges
, p. 78 - 85 (2019)
In this study, we prepared a magnetic metal–graphene nanocomposite for the synthesis of substituted biaryls via Suzuki cross coupling and homo coupling reaction of aryl halides. The magnetic few layer graphene composite was synthesized by using one-step electrochemical exfoliation of graphite foil in aqueous iron (II) ammonium sulfate as electrolyte without using of any additive or corrosive media. Then, Fe2O3@FLG composite was used an efficient support for the immobilization and suitable dispersing of palladium nanoparticles. The obtained Fe2O3@FLG@Pd0 nanocomposite was characterized using FT-IR, SEM, TEM, EDS, XRD, VSM and ICP-AES analysis. Very low loading of this catalyst was displayed high activity in the producing substituted biaryls. It simply recovered from the reaction mixture and reused without any pre-activation in six consecutive runs with no loss of its catalytic activity or the observation of any detectable palladium leaching process.
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.
