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Charge-transfer complex formations of tetracyanoquinone (cyanil) and aromatic electron donors
Single-electron oxidants are the primary reagents for investigations of the new oxidants and the development of electron-accepting materials for application in optoelectronics. Quinones are the well-known class of the neutral single-electron oxidants. Here, we present the properties of the strongest neutral electron acceptor of this class tetracyanoquinone (cyanil) and investigate its electron-accepting strength by analyzing the charge-transfer complex formations with the aromatic donor molecules. Charge-transfer complexes of tetracyanoquinone with aromatic electron donors are characterized spectroscopically in solution and isolated as the single crystals.
Jalilov, Almaz S.,Lu, Jianjiang,Kochi, Jay K.
p. 35 - 41
(2016)
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Hendrickson
p. 1251
(1961)
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Photo-Switchable Self-Assemblies Based on Thymine-Containing Bolaamphiphiles
The photoswitching of photosensitive bolaamphiphiles based on thymine was investigated. Topochemical principles were applied to create light-responsive supra-amphiphiles by the utilisation of dynamic covalent bonds created by the photo-dimerisation of a DNA base, thymine. In order to induce the photo-dimerisation of thymine, two bolaamphiphilic molecules were designed and synthesised to meet the required [2 π+2 π] photo-cycloaddition conditions. The amphiphiles were synthesised with different spacers and their photo-reversibility and morphologies were studied by using UV/Vis, NMR and infrared spectroscopy, rheometry, dynamic light scattering and transmission electron microscopy.
Al-Shereiqi, Ahmed S.,Boyd, Ben J.,Saito, Kei
p. 1135 - 1144
(2017)
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A second-generation dendrimer with six 2,9-dimethyl-1,10-phenanthroline units as ligand for copper-catalyzed reactions
2,9-Dimethyl-1,10-phenanthroline (neocuproine, 1) has been attached to dendritic structures through its 5-position providing a trimer 7 and the hexamers 11 and 12. The copper-binding capability of the hexamer 12 has been studied, and the 6:1 complex has been used to catalyze the Cu +-promoted substitution of an iodoarene 14 to give an aryl ether 15. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Lüning, Ulrich,Eggert, Jan P. W.,Hagemann, Kathrin
p. 2747 - 2752
(2006)
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Pulse Radiolytic Investigations of Aqueous Solutions of Methoxybenzene Cation Radicals: The Effect of Colloidal RuO2
The formation and decay of the radical cations of 1,4-dimethoxybenzene (DMB) and 1,2,4,5-tetramethoxybenzene (TMB) were investigated by the pulse radiolysis technique in the absence and the presence of colloidal RuO2 particles.DMB2. was obtained only by T12+ oxidation of DMB while TMB+.+ was produced by oxidation of TMB using both T12+ and Br2-.In the absence of RuO2 both DMB.+ and TMB.+ decay predominantly via a second-order process, although there is a contribution of a pseudo-first-order reaction.The rate constants for these reactions are reported.RuO2 colloidal particles catalyze the decay of both TMB.+ and DMB.+.The reactions of TMB.+ with RuO2 were found to depend on pH, pulse intensity, and colloidal concentration.At pH 3-4, adsorbtion of TMB.+ to the colloid is observed, followed by the decay of the remaining TMB.+ in the bulk.At higher pHs, loading of the RuO2 colloid by positive holes takes place until equilibrium is archieved between loaded holes and TMB.+ and again the remaining TMB.+ decays at a later stage.The fraction of TMB.+ that loads the colloidal particles increases with both pH and .It is also suggested that DMB.+ loads the RuO2 at the pH where experiments were performed. (TMB)2 and (DMB)2 dimers (or higher oligomers) are suggested to be the final products both in absence and presence of RuO2.No O2 is formed with the RuO2 colloid despite a favorable redox potential for water oxidation.
Brandys, Marek,Sasson, Richard E.,Rabani, Joseph
p. 953 - 962
(1987)
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Intramolecular hydrogen bonding and molecular structure of 2,5-dihydroxyterephthalaldehyde and 4,6-dihydroxyisophthalaldehyde: A gas-phase electron diffraction and ab initio molecular orbital study
The molecular structure of 2,5-dihydroxyterephthalaldehyde has been determined from a joint electron diffraction/ab initio investigation, and the molecular structure of 4,6-dihydroxyisophthalaldehyde has been obtained from ab initio calculations at the MP2/6-31G* level. There is considerable intramolecular hydrogen bonding in these structures manifested by the O...H and O...O distances as well as by the structural changes in the rest of the molecule. These changes are consistent with the notion of resonance-assisted hydrogen bonding. The hydrogen bonding is somewhat stronger in 4,6-dihydroxyisophthalaldehyde than in 2,5-dihydroxyterephthalaldehyde, and this difference may be linked to the difference in the mutual positioning of the interacting formyl and hydroxy groups in these molecules.
Borisenko, Konstantin B.,Zauer, Karoly,Hargittai, Istvan
p. 19303 - 19309
(1996)
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Photogeneration of Radical Cations from Aqueous Methoxylated Benzenes
Formation of radical cations resulting from photoinduced electron ejection from methoxylated benzenes in aqueous solutions has been observed.
Grabner, Gottfried,Rauscher, Walter,Zechner, Josef,Getoff, Nikola
p. 222 - 223
(1980)
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Hollow, mesoporous, eutectic Zn1?xMgxO nano-spheres as solid acid-base catalysts for the highly regio-selectiveO-methylation of 1,2-diphenols
The highly regio-selectiveO-methylation of catechol with dimethyl carbonate (DMC), catalyzed by a solid acid-base catalyst, is an environmentally friendly chemical process for industrial production of guaiacol. However, a guaiacol yield below 84% and high reaction temperature above 280 °C limit its industrial application. Here, hollow, mesoporous Zn1?xMgxO nano-spheres with a eutectic structure, denoted as Zn1?xMgxO HMNSs (x= 0.012-0.089), are facilely fabricatedviathe calcination of Mg2+/Zn2+ion-adsorbing carbon spheres at 500 °C in air. In theO-methylation of catechol with DMC at 180 °C, Zn1?xMgxO HMNSs (x= 0.052) afford guaiacol in 95.5% yield with a complete catechol conversion. Furthermore, 89.0-95.3% mono-ether yields with high 1,2-diphenol conversions (94.5-100%) are also obtained for the other 1,2-diphenols bearing -CH3and -Br groups. Moreover, a plausible mechanism for highly selectiveO-methylation of catechol with DMC is proposed, in which the single-site activation and double-site activation of phenolic hydroxyls by the basic oxygen of Mg-O afford guaiacol and veratrole, respectively.
Liu, Jie,Ma, Xuebing,Wang, Xuri,Xie, Guangxin,Yin, Zuyong,Zhang, Jianing
p. 7454 - 7466
(2021/11/23)

Copper-Catalyzed Methoxylation of Aryl Bromides with 9-BBN-OMe
A Cu-catalyzed cross-coupling reaction between aryl bromides and 9-BBN-OMe to provide aryl methyl ethers under mild conditions is reported. The oxalamide ligand BHMPO plays a key role in the transformation. Various functional groups on bromobenzenes are well tolerated, providing the desired anisole products in moderate to high yields.
Li, Chen,Song, Zhi-Qiang,Wang, Dong-Hui,Wang, Jing-Ru
supporting information
p. 8450 - 8454
(2021/11/17)

B(C6F5)3-Catalyzed Hydroarylation of Aryl Alkynes for the Synthesis of 1,1-Diaryl and Triaryl Substituted Alkenes
A new strategy for the synthesis of 1,1-diaryl and triarylsubstituted alkenes has been developed utilizing B(C6F5)3-catalyzed hydroarylation of alkynes with phenols. The method provides a direct route to ortho-alkenylated phenols with both terminal and internal alkynes. The reactions show excellent regioselectivity, and good stereoselectivity was observed for the hydroarylation of internal alkynes. Computational and experimental studies suggest that for the reaction of internal alkynes and phenols, an acid-catalyzed isomerization mechanism involving two tertiary carbonium ion intermediates is responsible for the formation of Z-triaryl substituted alkenes.
Chen, Hui,Gao, Liuzhou,Liu, Xueting,Wang, Guoqiang,Li, Shuhua
supporting information
p. 5238 - 5242
(2021/10/19)

Methylation with Dimethyl Carbonate/Dimethyl Sulfide Mixtures: An Integrated Process without Addition of Acid/Base and Formation of Residual Salts
Dimethyl sulfide, a major byproduct of the Kraft pulping process, was used as an inexpensive and sustainable catalyst/co-reagent (methyl donor) for various methylations with dimethyl carbonate (as both reagent and solvent), which afforded excellent yields of O-methylated phenols and benzoic acids, and mono-C-methylated arylacetonitriles. Furthermore, these products could be isolated using a remarkably straightforward workup and purification procedure, realized by dimethyl sulfide‘s neutral and distillable nature and the absence of residual salts. The likely mechanisms of these methylations were elucidated using experimental and theoretical methods, which revealed that the key step involves the generation of a highly reactive trimethylsulfonium methylcarbonate intermediate. The phenol methylation process represents a rare example of a Williamson-type reaction that occurs without the addition of a Br?nsted base.
Chan, Bun,Lui, Matthew Y.,Lui, Yuen Wai
(2022/01/08)

NON-LINEAR CHROMOPHORE, PHOTOREFRACTIVE COMPOSITE COMPRISING THE SAME AND PHOTOREFRACTIVE DEVICE
The present invention relates to a non-linear optical dye, to a photorefractive composite comprising the same, and to a photorefractive device and, more specifically, to a non-linear optical dye with improved response speed to an applied electric field by controlling a molecular structure, to a photorefractive composite comprising the same, and to a photorefractive device. The non-linear optical dye according to the present invention has an alkyl group or an alkoxy group having 1 to 10 carbon atoms.
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(2021/02/05)

A highly stable all-in-one photocatalyst for aryl etherification: The NiIIembedded covalent organic framework
The efficient conversion of aryl bromides to the corresponding aryl alkyl ethers by dual nickel/photocatalysis has seen great progress, but difficulties of recycling the photosensitizer or nickel complexes cause problems of sustainability. Here, we report the design of a novel, highly stable vinyl bridge 2D covalent organic framework (COF) containing Ni, which combines the role of photosensitizer and reactive site. The as-prepared sp2c-COFdpy-Ni acts as an efficient heterogeneous photocatalyst for C-O cross coupling. The sp2c-COFdpy-Ni can be completely recovered and used repeatedly without loss of activity, overcoming the limitations of the prior methods. Preliminary studies reveal that strong interlayer electron transfer may facilitate the generation of the proposed intermediate sp2c-COFdpy-NiI in a bimolecular and self-sustained manner. This all-in-one heterogeneous photocatalyst exhibits good compatibility of substrates and tolerance of functional groups. The successful attempt to expand the 2D COFs with this new catalyst into photocatalytic organic transformation opens an avenue for photoredox/transition metal mediated coupling reactions.
Chen, Hao,Dong, Wenbo,Hu, Jianxiang,Rao, Li,Wang, Pei,Wang, Shengyao,Xiang, Yonggang,Yang, Yi
p. 5797 - 5805
(2021/08/23)

Light assisted O-alkylation of phenols to ethers using layered double oxides catalyst under green and mild conditions
O-alkylation of phenols with dialkyl carbonates to ethers over layered double oxides (LDOs) catalyst under light irradiation is described. A base additive is not required when using the longer-chain diethyl carbonate as an alkylating agent owing to the sufficient basicity provided by LDOs. The synergism of substrate phenols molecules absorbing light to reach the first excited states with acid–base pairs of catalyst enhanced the interaction of reactant molecules with the surface of LDOs, simultaneously accelerating the cleavage of phenolic hydroxyl groups. A variety of phenols are tolerated in this system. This work reports a simple and environmentally benign catalytic process for the dehydrogenation of phenolic hydroxyl groups.
Wang, Ruiyi,Wang, Xiaoyu,Zheng, Zhanfeng
(2020/07/03)

Practical Transition-Metal-Free Protodeboronation of Arylboronic Acids in Aqueous Sodium Hypochlorite
A concise and practical method was developed for the protodeboronation of arylboronic acids under mild conditions in aqueous NaClO at 100 °C. The strategy is low-cost, transition-metal-free, and base-free.
Li, Minxin,Tang, Yanling,Gao, Jinchun,Rao, Gaoxiong,Mao, Zewei
p. 2039 - 2042
(2020/10/21)

A silica-gel accelerated [4 + 2] cycloaddition-based biomimetic approach towards the first total synthesis of magterpenoid C
The first total synthesis of magterpenoid C has been realized via a silica gel accelerated biomimetic Diels-Alder reaction between β-myrcene and randaiol derived quinone. However, application of similar strategy towards magterpenoid B via a protective Diels-Alder reaction failed to deliver the natural product.
Kumar, Dileep,Kumar, Virendra,Salam, Abdus,Khan, Tabrez
(2019/09/17)

On/Off O2 Switchable Photocatalytic Oxidative and Protodecarboxylation of Carboxylic Acids
Photoredox catalysis in recent years has manifested a powerful branch of science in organic synthesis. Although merging photoredox and metal catalysts has been a widely used method, switchable heterogeneous photoredox catalysis has rarely been considered. Herein, we open a new window to use a switchable heterogeneous photoredox catalyst which could be turned on/off by changing a simple stimulus (O2) for two opponent reactions, namely, oxidative and protodecarboxylation. Using this strategy, we demonstrate that Au@ZnO core-shell nanoparticles could be used as a switchable photocatalyst which has good catalytic activity to absorb visible light due to the localized surface plasmon resonance effect of gold, can decarboxylate a wide range of aromatic and aliphatic carboxylic acids, have multiple reusability, and are a reasonable candidate for synthesizing both aldehydes/ketones and alkane/arenes in a large-scale set up. Some biologically active molecules are also shown via examples of the direct oxidative and protodecarboxylation which widely provided pharmaceutical agents.
Bazyar, Zahra,Hosseini-Sarvari, Mona
p. 13503 - 13515
(2019/10/11)

Catalytic hydrodebromination of aryl bromides by cobalt tetra-butyl porphyrin complexes with EtOH
Hydrodebromination of aryl bromides catalyzed by electron rich and sterically unhindered cobalt 5,10,15,20-tetrabutylporphyrin was achieved at mild conditions in good yields employing EtOH as the hydrogen source. The catalytic efficiency was enhanced compared with previously reported by cobalt tetra-aryl porphyrin catalysts. A revised mechanism of single electron transfer was proposed.
Chen, Chen,Zuo, Huiping,Chan, Kin Shing
p. 510 - 517
(2019/01/04)

Oxalic Diamides and tert-Butoxide: Two Types of Ligands Enabling Practical Access to Alkyl Aryl Ethers via Cu-Catalyzed Coupling Reaction
A robust and practical protocol for preparing alkyl aryl ethers has been developed, which relies on using two types of ligands to promote Cu-catalyzed alkoxylation of (hetero)aryl halides. The reaction scope is very general for a variety of coupling partners, particularly for challenging secondary alcohols and (hetero)aryl chlorides. In case of coupling with aryl chlorides and bromides, two oxalic diamides serve as the powerful ligands. The tert-butoxide is first demonstrated as a ligand for Cu-catalyzed coupling reaction, leading to alkoxylation of aryl iodides complete at room temperature. Additionally, a number of carbohydrate derivatives are applicable for this coupling reaction, affording the corresponding carbohydrate-aryl ethers in 29-98% yields.
Chen, Zhixiang,Jiang, Yongwen,Zhang, Li,Guo, Yinlong,Ma, Dawei
p. 3541 - 3549
(2019/02/26)

Method for hydrogenation reduction of organic halide by semiconductor photocatalysis
The invention discloses a method for hydrogenation reduction of organic halide by semiconductor photocatalysis. Semiconductor materials boron, nitrogen and carbon serve as photocatalysts, and the organic halide C-X (X=Br and Cl) is hydrogenated and reduced into a dehalogenated compound. The boron, nitrogen and carbon are used for hydrogenating and reducing the organic halide, the reaction processis simple in operation, catalysis effects are good, catalysis can be performed in visible light, conditions are mild, and the method is low in cost, meets practical production requirements and has a large application potential.
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(2018/09/13)

An Additive-Free, Base-Catalyzed Protodesilylation of Organosilanes
We report an additive-free, base-catalyzed C-, N-, O-, and S-Si bond cleavage of various organosilanes in mild conditions. The novel catalyst system exhibits high efficiency and good functional group compatibility, providing the corresponding products in good to excellent yields with low catalyst loadings. Overall, this transition-metal-free process may offer a convenient and general alternative to current employing excess bases, strong acids, or metal-catalyzed systems for the protodesilylation of organosilanes.
Yao, Wubing,Li, Rongrong,Jiang, Huajiang,Han, Deman
p. 2250 - 2255
(2018/02/23)

Base-promoted nucleophilic fluoroarenes substitution of C–F bonds
With the use of KOH/DMSO as the superbase medium, the nucleophilic fluoroarene substitution for C–F bonds is presented. The transformation proceeds smoothly with the use of fluoroarenes bearing not only electron-withdrawing group, but also electron-donating group and a variety of nucleophiles such as alcohols, phenols, amines, amides and nitrogen-heterocyclic compounds. The double nucleophilic substitution using ortho-difluoroarenes and nucleophiles bearing ortho-dinucleophilic groups results in the formation of 2,3-dihydro-1,4-benzodioxins, dibenzo[b,e][1,4]dioxins and 10H-phenoxazines in moderate to good yields.
Su, Ji,Chen, Qian,Lu, Le,Ma, Yuan,Auyoung, George Hong Lok,Hua, Ruimao
supporting information
p. 303 - 307
(2017/12/11)

Efficient synthesis of α-substituted-α-arylmethyl phosphonates using trichloroacetimidate C–C coupling method
A simple convenient protocol for the synthesis of diethyl α,α-diaryl methylphosphonate derivatives 5a-f, 6b-f, 7a-f and 8a-f, diethyl α-alkenyl α-aryl methylphosphonates 9a-d and 10a-d and α-(oxoalkyl) α-aryl methylphosphonate 11a-d and 12a-d is described. Trichloroacetimidates 3a-d were treated with activated arenes, styrene, allyltrimethylsilane or silylenol ethers C-nucleophiles in the presence TMSOTf to afford the desired products in good yields and short reaction time.
Fathalla, Walid,Pazdera, Pavel,El-Rayes, Samir,Ali, Ibrahim.A.I.
p. 1681 - 1691
(2018/03/01)

Shifting Chemical Equilibria in Flow - Efficient Decarbonylation Driven by Annular Flow Regimes
To efficiently drive chemical reactions, it is often necessary to influence an equilibrium by removing one or more components from the reaction space. Such manipulation is straightforward in open systems, for example, by distillation of a volatile product from the reaction mixture. Herein we describe a unique high-temperature/high-pressure gas/liquid continuous-flow process for the rhodium-catalyzed decarbonylation of aldehydes. The carbon monoxide released during the reaction is carried with a stream of an inert gas through the center of the tubing, whereas the liquid feed travels as an annular film along the wall of the channel. As a consequence, carbon monoxide is effectively vaporized from the liquid phase into the gas phase and stripped from the reaction mixture, thus driving the equilibrium to the product and preventing poisoning of the catalyst. This approach enables the catalytic decarbonylation of a variety of aldehydes with unprecedented efficiency with a standard coil-based flow device.
Gutmann, Bernhard,Elsner, Petteri,Glasnov, Toma,Roberge, Dominique M.,Kappe, C. Oliver
supporting information
p. 11557 - 11561
(2016/02/19)

Microwave-assisted methylation of dihydroxybenzene derivatives with dimethyl carbonate
Using a focused microwave reactor, methylation with dimethyl carbonate (DMC) of 1,2- and 1,4-dihydroxybenzene derivatives, found in the product spectrum of lignin depolymerisation, leads to the respective aromatic bis-methyl ethers with excellent isolated yields. Stoichiometric as well as catalytic amounts of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) are effective for the bis-methylation of these dihydroxybenzenes at relatively mild temperatures (160-190 °C). Conversion of resorcinol (1,3-dihydroxybenzene) under similar conditions leads to a mixture of 1,3-dimethoxybenzene and methyl 2,4-dimethoxybenzoate. The unusual reactivity of resorcinol's phenyl ring towards DMC can be explained by the synergic effect of its two strongly activating ortho/para directing groups.
Lui, Matthew Y.,Lokare, Kapil S.,Hemming, Ellen,Stanley, Jessica N.G.,Perosa, Alvise,Selva, Maurizio,Masters, Anthony F.,Maschmeyer, Thomas
p. 58443 - 58451
(2016/07/06)

MCM-41-immobilized 1,10-phenanthroline-copper(i) complex: A highly efficient and recyclable catalyst for the coupling of aryl iodides with aliphatic alcohols
A heterogeneous C-O coupling reaction between aryl iodides and aliphatic alcohols was achieved in neat alcohol or toluene at 110 °C in the presence of 10 mol% of the MCM-41-immobilized 1,10-phenanthroline-copper(i) complex [MCM-41-1,10-phen-CuI] with Cs2CO3 as a base, yielding a variety of aryl alkyl ethers in good to excellent yields. The new heterogeneous copper catalyst can easily be prepared by a simple procedure from commercially available and inexpensive reagents, and recovered by filtration of the reaction solution and recycled at least 8 times without significant loss of activity.
Lin, Yang,Cai, Mingzhong,Fang, Zhiqiang,Zhao, Hong
p. 85186 - 85193
(2016/10/12)

Selective O-methylation of phenols and benzyl alcohols in simple pyridinium based ionic liquids
Synthesis of pyridinium based ionic liquids were reported and applied as catalyst for the selective O-methylation of phenols and benzyl alcohols. The reactions were carried out by using dimethylcarbonate (DMC) as the methylating agent. High selectivity, high yield and recyclability of the ionic liquids are important features of the reactions.
Das, Pranab Jyoti,Das, Jupitara
p. 94 - 98
(2015/06/08)

Methylation of phenol and its derivatives with dimethyl carbonate in the presence of Mn2(CO)10, W(CO)6, and Co2(CO)8
Aryl methyl ethers were synthesized by reactions of phenol, substituted phenols, and α- and β-naphthols with dimethyl carbonate in the presence of manganese, tungsten, and cobalt carbonyls. Optimal reactant and catalyst ratios and reaction conditions were found to ensure selective formation of aryl methyl ethers.
Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.
p. 330 - 334
(2015/05/04)

ALKYLATION OF PHENOLIC COMPOUNDS
The invention relates to a process for O-alkyiation of a phenolic compound comprising at least two hydroxyl groups bonded to an aromatic hydrocarbon, the process comprising reacting the phenolic compound with an alkylating agent in the presence of a base, at a suitable reaction temperature and for a suitable time period, thereby alkylating the at least two hydroxy] groups. The invention also relates to O-alkylaled phenolic compounds produced by this process.
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(2015/04/28)

Metal-free carbonylations by photoredox catalysis
The synthesis of benzoates from aryl electrophiles and carbon monoxide is a prime example of a transition-metalcatalyzed carbonylation reaction which is widely applied in research and industrial processes. Such reactions proceed in the presence of Pd or Ni catalysts, suitable ligands, and stoichiometric bases. We have developed an alternative procedure that is free of any metal, ligand, and base. The method involves a redox reaction driven by visible light and catalyzed by eosin Y which affords alkyl benzoates from arene diazonium salts, carbon monoxide, and alcohols under mild conditions. Tertiary esters can also be prepared in high yields. DFT calculations and radical trapping experiments support a catalytic photoredox pathway without the requirement for sacrificial redox partners.
Majek, Michal,Von Wangelin, Axel Jacobi
supporting information
p. 2270 - 2274
(2015/02/19)

Direct evidence for secondary interactions in planar and nonplanar aromatic π-conjugates and their photophysical characteristics in solid-state assemblies
Direct evidence for non-covalent secondary interactions in planar and nonplanar aromatic π-conjugates and their solid-state assemblies is established. A series of horizontally, vertically, and radially expanded oligo(phenylenevinylene)s (H-OPVs, V-OPVs, and R-OPVs, respectively) were designed with a fixed π-core and variable alkyl chain lengths on the periphery. Single-crystal structures of the OPVs were resolved to trace the secondary interactions that direct the solid-state self-organization and molecular packing of the chromophores. The H-OPVs were found to be planar, and they did not show any secondary interactions in the crystal lattices. The V-OPVs and R-OPVs were found to be nonplanar and to exhibit multiple CH/π hydrogen-bonding interactions among aryl hydrogen donors and acceptors. The enthalpies of the melting and crystallization transitions revealed that the planar H-OPVs are highly crystalline compared with the nonplanar R-OPVs and V-OPVs. Polarized light microscopy studies revealed the formation of one-dimensional nematic mesophases in H-OPVs. The absolute solid-state photoluminescence quantum yields (PLQYs) of the OPVs were determined using an integrating sphere setup. The highly packed H-OPVs showed low PLQYs compared with those of the weakly packed V-OPVs and R-OPVs. Time-resolved fluorescence decay measurements revealed that the excited-state decay dynamics of highly packed H-OPVs was much faster with respect to their low PLQYs. The decay profiles were found to be relatively slow (with higher life time (τ)) in the V-OPVs and R-OPVs. A field-effect transistor (FET) device was constructed for an OPV sample that showed a hole carrier mobility in the range of 10-5 cm2 V-1 s-1. The present investigation thus provides a new opportunity to trace the role of secondary interactions on π-conjugated mesophase self-assemblies and their solid-state emission and FET devices, more specifically based on OPV chromophores.
Goel, Mahima,Narasimha, Karnati,Jayakannan, Manickam
p. 5102 - 5112
(2015/04/27)

Palladium-catalyzed methoxylation of aromatic chlorides with borate salts
Herein we disclose a simple palladiumcatalyzed transformation for the methoxylation of aromatic chlorides with tetramethoxyborate salts. The procedure provides a new and efficient synthetic tool for the introduction of a methoxy group into aromatic systems. In addition, the reaction can be achieved using a wide range of aromatic and heteroaromatic chlorides, the cheapest class of halides.
Tolnai, Gergely L.,Petho, Bálint,Králl, Péter,Nováka, Zoltán
p. 125 - 129
(2014/03/21)

π-complexation in nickel-catalyzed cross-coupling reactions
The kinetic isotope effect (KIE) is used to experimentally elucidate the first irreversible step in oxidative addition reactions of a zerovalent nickel catalyst to a set of haloarene substrates. Halogenated o-methylbenzene, dimethoxybenzene, and thiophene derivatives undergo intramolecular oxidative addition through irreversible π-complexation. Density functional theory computations at the B3LYP-D3/TZ2P-LANL2TZ(f)-LANL08d level predict η2-bound π-complexes are generally stable relative to a solvated catalyst plus free substrate and that ring-walking of the Ni(0) catalyst and intramolecular oxidative addition are facile in these intermediates.
Sontag, S. Kyle,Bilbrey, Jenna A.,Huddleston, N. Eric,Sheppard, Gareth R.,Allen, Wesley D.,Locklin, Jason
p. 1836 - 1841
(2014/03/21)

Mild and general palladium-catalyzed synthesis of methyl aryl ethers enabled by the use of a palladacycle precatalyst
A general method for the Pd-catalyzed coupling of methanol with (hetero)aryl halides is described. The reactions proceed under mild conditions with a wide range of aryl and heteroaryl halides to give methyl aryl ethers in high yield.
Cheung, Chi Wai,Buchwald, Stephen L.
supporting information
p. 3998 - 4001
(2013/09/02)

Amino acid intercalated layered double hydroxide catalyzed chemoselective methylation of phenols and thiophenols with dimethyl carbonate
Sixteen different amino acids are intercalated into Mg-Al layered double hydroxides (LDHs) by the reconstruction method and are characterized by powder XRD and FT-IR. The intercalated amino acid-LDHs (AA-LDHs) are used as catalysts for chemoselective O-methylation of phenol and S-methylation of thiophenol with dimethyl carbonate (DMC) as a green methylating agent. The intercalation behavior of various amino acids is influenced by various structural features of amino acids, namely, carbon chain length, structure, and physicochemical properties. In particular, amino acids possessing a hydrophobic side-chain show higher catalytic activity. A suitable reaction mechanism is proposed. The catalyst can also be recycled.
Subramanian, Thirumeni,Dhakshinamoorthy, Amarajothi,Pitchumani, Kasi
p. 7167 - 7170
(2013/12/04)

Liquid crystalline bis(N-salicylideneaniline)s: Synthesis and thermal behavior of constitutional isomers
The first examples of mesogenic bis(N-salicylideneaniline)s (BSANs), wherein two lipophilic (half-disk shaped) entities are interlinked through the dihydroxydiformylbenzene core, were synthesized and characterized. In particular, three constitutional (positional) isomeric BSANs were prepared by the facile twofold condensation of 3,4,5-tris(alkoxy)anilines with 2,3-dihydroxyterephthalaldehyde, 4,6-dihydroxyisophthalaldehyde, and 2,5-dihydroxyterephthalaldehyde and their structures were established by elemental analyses, FT-IR, 1H NMR, and 13C NMR. Proton NMR experiments demonstrated their existence in enol-imine (OH) form solely. Polarizing optical microscopic, differential scanning calorimetric, and powder X-ray diffraction studies evidenced the occurrence of columnar mesomorphism in two sets of isomers.
Hiremath, Uma S.
p. 3419 - 3423
(2013/07/04)

Antimony(V) chloride as an efficient reagent for deprotection of methyl ethers
This paper proposes a new and efficient method for the deprotection of methyl ethers using antimony pentachloride at ambient temperature. The procedure described here is a facile and practical method for the removal of the methyl group from aryl and benzyl methyl ethers. High selectivity was observed for the removal of the methyl group from dimethoxyarenes. The notable advantages of this protocol are mild reaction conditions, high yields, and the facility of workup procedure. The mechanism of the ether cleavage is proposed to explain this new reaction. Georg Thieme Verlag Stuttgart New York.
Saadati, Fariba,Meftah-Booshehri, Hamid
p. 1702 - 1706
(2013/09/02)

Development of DANDYs, new 3,5-diaryl-7-azaindoles demonstrating potent DYRK1A kinase inhibitory activity
A series of 3,5-diaryl-1H-pyrrolo[2,3-b]pyridines were synthesized and evaluated for inhibition of DYRKIA kinase in vitro. Derivatives having hydroxy groups on the aryl moieties (2c, 2j-l) demonstrated high inhibitory potencies with Kis in the low nanomolar range. Their methoxy analogues were up to 100 times less active. Docking studies at the ATP binding site suggested that these compounds bind tightly to this site via a network of multiple H-bonds with the peptide backbone. None of the active compounds were cytotoxic to KB cells at 10-6 M. Kinase profiling revealed that compound 2j showed 2-fold selectivity for DYRK1A with respect to DYRK2 and DYRK3.
Gourdain, Stéphanie,Dairou, Julien,Denhez, Clément,Bui, Linh Chi,Rodrigues-Lima, Fernando,Janel, Nathalie,Delabar, Jean M.,Cariou, Kevin,Dodd, Robert H.
p. 9569 - 9585
(2014/01/06)

Metal-free arylations via photochemical activation of the Ar-OSO 2R bond in aryl nonaflates
The photolysis of electron-rich aryl nonaflates (ArONfs) in protic media was investigated and heterolysis of the Ar-OS bond (from 3ArONf) took place. The reaction generated a triplet phenyl cation that added to π-bond nucleophiles. This metal-free arylation method was made further useful by adopting in situ preparation of ArONf from the corresponding phenol.
Raviola, Carlotta,Canevari, Veronica,Protti, Stefano,Albini, Angelo,Fagnoni, Maurizio
supporting information
p. 2704 - 2708
(2013/10/08)

Synthesis of aryl ethers from benzoates through carboxylate-directed C-H-activating alkoxylation with concomitant protodecarboxylation
One in, one out: In the presence of a copper/silver bimetallic catalyst system, aromatic carboxylate salts undergo ortho C-H alkoxylation with concomitant loss of the carboxylate directing group in a protodecarboxylation step (see scheme, FG=functional group). This process provides a convenient synthetic access to the important class of aromatic ethers from widely available carboxylic acids. Copyright
Bhadra, Sukalyan,Dzik, Wojciech I.,Goo?en, Lukas J.
p. 2959 - 2962
(2013/04/10)

Efficient indium-mediated dehalogenation of aromatics in ionic liquid media
An efficient indium-mediated dehalogenation reaction of haloaromatics and haloheteroaromatics in ionic liquids has been studied. This method is simple and effective in the presence of [bmim]Br. Furthermore, this methodology is environmentally friendly compared with conventional ones.
Canete, Alvaro F.,Salas, Cristian O.,Zacconi, Flavia C.
p. 398 - 407
(2013/03/13)

Tuning the moisture and thermal stability of metal-organic frameworks through incorporation of pendant hydrophobic groups
An isostructural series of NbO-type porous metal-organic frameworks (MOFs) with different dialkoxy-substituents of formula Cu2(TPTC-OR) (TPTC-OR = 2′,5′-di{alkyl}oxy-[1,1′:4′,1″-terphenyl]-3, 3″,5,5″-tetracarboxylate, R = Me, Et, nPr, nHex) has been synthesized and characterized. The moisture stability of the materials has been evaluated, and a new superhydrophobic porous MOF has been identified. The relationship between pendant side chain length and thermal stability has been analyzed by in situ synchrotron powder X-ray diffraction, showing decreased thermal stability as the side chain length is increased, contradictory to thermogravimetric decomposition studies. Additionally, the four materials exhibit moderate Brunauer-Emmett-Teller (BET) and Langmuir surface areas (1127-1396 m2 g-1 and 1414-1658 m2 g -1) and H2 capacity up to 1.9 wt % at 77 K and 1 bar.
Makal, Trevor A.,Wang, Xuan,Zhou, Hong-Cai
p. 4760 - 4768
(2013/12/04)

Synthesis and characterization of near-infrared emissive BODIPY-based conjugated polymers
Three novel BODIPY-based conjugated polymers could be synthesized via palladium-catalyzed Sonogashira coupling reaction. Compared with BODIPY model derivatives, the polymers can emit in the range from deep-red to near-infrared region with emission spectral maxima at = 640-660 nm and exhibit moderate fluorescent quantum yield from 0.23 to 0.26. Density functional theory (DFT) calculations are performed on three polymers repeat units, and HOMO and LUMO energy levels of the conjugated polymers are estimated. Georg Thieme Verlag Stuttgart · New York.
Wu, Yuanzhao,Ma, Xiao,Jiao, Jiemin,Cheng, Yixiang,Zhu, Chengjian
supporting information; scheme or table
p. 778 - 782
(2012/07/27)

Kinetic and spectroscopic studies of aerobic copper(II)-catalyzed methoxylation of arylboronic esters and insights into aryl transmetalation to copper(II)
We previously reported a preliminary mechanistic study of aerobic Cu(OAc)2-catalyzed methoxylation of 4-tolylboronic ester (King et al. J. Am. Chem. Soc., 2009, 131, 5044-5045), which revealed that aryl transmetalation from the boronic ester to CuII is the turnover-limiting step. In the present study, more thorough kinetic and spectroscopic studies provide additional insights into the transmetalation pathway and identity of the CuII catalyst resting state(s). EPR spectroscopic studies show that at least two copper(II) species are present under catalytic conditions, and their relative populations vary as a function of reaction time and acidity of the arylboronic ester and are influenced by addition of acetic acid or acetate to the reaction mixture. Analysis of kinetic data and 11B NMR and EPR spectra under diverse reaction conditions suggests that aryl transmetalation occurs from a tetracoordinate, anionic boronate to a cationic CuII species, mediated by a methoxide bridge.
King, Amanda E.,Ryland, Bradford L.,Brunold, Thomas C.,Stahl, Shannon S.
p. 7948 - 7957
(2013/01/16)

C,N-chelated organotin(IV) compounds as catalysts for transesterification and derivatization of dialkyl carbonates
The potential catalytic activity of selected C,N-chelated organotin(IV) compounds (e.g. halides and trifluoroacetates) for derivatization of both dimethyl carbonate (DMC) and diethyl carbonate (DEC) was investigated. Some tri-, di- and monoorganotin(IV) species (LCN(n-Bu)2SnCl (1), LCN(n-Bu)2SnCl.HCl (1a), LCN(n-Bu) 2SnI (2), LCNPh2SnCl (3), LCNPh 2SnI (4), LCN(n-Bu)SnCl2 (5), L CNSnBr3 (6) and [LCNSn(OC(O)CF 3)]2(μ-O)(μ-OC(O)CF3)2 (7)) bearing the LCN moiety (LCN = 2-(N,N-dimethylaminomethyl) phenyl-) were assessed as catalysts for reactions of both DMC and DEC with various substituted anilines. The catalytic activities of 4 and 7 for derivatization of DMC with p-substituted phenols were studied for comparison with the standard base K2CO3/Silcarbon K835 catalyst (catalyst 8). The composition of resulting reaction mixtures was monitored by multinuclear NMR spectroscopy, GC and GC-MS techniques. In general, catalysts 1, 3 and 7 exhibited the highest catalytic activity for all reactions studied, while some of them yielded selectively carbonates, carbamates, lactam or substituted urea. Copyright
Weidlich, Tomas,Dusek, Libor,Vystrcilova, Barbora,Eisner, Ales,Svec, Petr,Ruzicka, Ales
experimental part
p. 293 - 300
(2012/10/07)

Alkyloxy substituted organic dyes for high voltage dye-sensitized solar cell: Effect of alkyloxy chain length on open-circuit voltage
Three novel organic dyes (SB1, SB2, and SB3) containing 4-(hexyloxy)-N-(4-(hexyloxy)phenyl)-N-phenylaniline as electron donor and cyanoacrylic acid as electron acceptor bridged by alkyloxy (methyl = SB1, propyl = SB2 and hexyl = SB3) substituted p-phenylenevinylene linkers have been synthesized. Density functional theory (DFT) has employed to study electron distribution and intramolecular charge transfer. Increase in alkyl chain length in alkyloxy substituent leads to increase in open-circuit voltage (V OC), which is found to be related to the increased electron lifetime at open-circuit condition. Under AM 1.5 G 1 sun light illumination (100 mW/cm2), an optimized SB3-sensitized cell show a short-circuit photocurrent density (JSC) of 12.83 mA/cm2, an open-circuit voltage (VOC) of 0.745 V and a fill factor (FF) of 0.64, corresponding to an overall conversion efficiency (η) of 6.12%. Little degradation in η observed over 40 days is indicative of long-term stability of the SB-series dyes.
Ko, Soo-Byung,Cho, An-Na,Kim, Mi-Jeong,Lee, Chang-Ryul,Park, Nam-Gyu
scheme or table
p. 88 - 98
(2012/04/04)

C-H/π-interaction-guided self-assembly in π-conjugated oligomers
We report CH/π hydrogen-bond-driven self-assembly in π-conjugated skeletons based on oligophenylenevinylenes (OPVs) and trace the origin of interactions at the molecular level by using single-crystal structures. OPVs were designed with appropriate pendants in the aromatic core and varied by hydrocarbon or fluorocarbon tails along the molecular axis. The roles of aromatic π-stack, van der Waals forces, fluorophobic effect and CH/π interactions were investigated on the theromotropic liquid crystallinity of OPV molecules. Single-crystal structures of hydrocarbon OPVs provided direct evidence for the existence of CH/π interactions between the π-ring (H-bond acceptor) and alkyl C-H (H-bond donor). The four important crystallographic parameters, dc-x=3.79 A, θ=21.49°, =150.25° and dHp-x=0.73 A, matched in accordance with typical CH/π interactions. The CH/π interactions facilitate the close-packing of mesogens in x-y planes, which were further protruded along the c axis producing a lamellar structure. In the absence of CH/π interactions, van der Waals interactions drove the assembly towards a Schlieren nematic texture. Fluorocarbon OPVs exhibited smectic liquid-crystalline textures that further underwent Smectic A (SmA) to Smectic C (SmC) phase transitions with shrinkage up to 11 %. The orientation and translational ordering of mesogens in the liquid-crystalline (LC) phases induced H- and J-type molecular arrangements in fluorocarbon and hydrocarbon OPVs, respectively. Upon photoexcitation, the H- and J-type molecular arrangements were found to emit a blue or yellowish/green colour. Time-resolved fluorescence decay measurements confirmed longer lifetimes for H-type smectic OPVs relative to that of loosely packed one-dimensional nematic hydrocarbon-tailed OPVs. Weak-force-driven self-assembly: CH/π hydrogen-bonding-driven diverse molecular self-assembly in π-conjugated molecules is reported (see figure). The self-organisation of π-conjugated mesogens in three-dimensional crystal lattices is proven to be vital for tuning the thermotropic liquid-crystalline phases and their emission colour. Copyright
Goel, Mahima,Jayakannan, Manickam
supporting information; experimental part
p. 2867 - 2874
(2012/05/04)

Cationic and radical intermediates in the acid photorelease from aryl sulfonates and phosphates
The irradiation of a series of phenyl sulfonates and phosphates leads to the quantitative release of acidity with a reasonable quantum yield (≈0.2). Products characterization, ion chromatography analysis and potentiometric titration are consistent with the intervening of two different paths in this reaction, viz. cationic with phosphates and (mainly) radical with sulfonates. The Royal Society of Chemistry and Owner Societies 2011.
Terpolilli, Marco,Merli, Daniele,Protti, Stefano,Dichiarante, Valentina,Fagnoni, Maurizio,Albini, Angelo
experimental part
p. 123 - 127
(2012/01/03)

On the reactivity of imidazole carbamates and ureas and their use as esterification and amidation reagents
The optimization, substrate scope, and mechanism of esterification and amidation of carboxylic acids mediated by imidazole-based reagents are discussed. The innate reactivity of carbonylimidazole reagents with a range of nucleophiles is also explored. New reagents developed for the synthesis of α,β-unsaturated esters are described, as are reagents for the preparation of tertiary amides directly from carboxylic acids.
Heller, Stephen T.,Sarpong, Richmond
experimental part
p. 8851 - 8859
(2011/12/02)

Palladium-catalyzed borylation of sterically demanding aryl halides with a silica-supported compact phosphane ligand
Immobile but active: A silica-supported "compact" phosphane, Silica-SMAP, can be used in the Pd-catalyzed borylation of aryl chlorides or bromides with bis(pinacolato)diboron (see scheme). The Silica-SMAP/Pd system significantly expands the substrate scope of the borylation toward sterically and electronically challenging aryl halides.
Kawamorita, Soichiro,Ohmiya, Hirohisa,Iwai, Tomohiro,Sawamura, Masaya
supporting information; experimental part
p. 8363 - 8366
(2011/10/09)

Microwave-assisted methylation of phenols with DMF-DMA
We evaluated the potential of N,N-dimethylformamide dimethylacetal (DMF-DMA) as a methylating agent for a library of para-substituted phenols under microwave irradiation. The rate of reaction was dictated by the electronic nature of the para-substituent. With an electron-withdrawing group the reaction was completed within 30 min. For electron-donating groups, the reaction times were 60 min. Esterification and enamino-ketone formation was also observed with carboxylic acid and ketone functional groups, respectively.
Belov, Pavel,Campanella, Veronica L.,Smith, Alison W.,Priefer, Ronny
experimental part
p. 2776 - 2779
(2011/06/19)

Unusual ipso substitution of diaryliodonium bromides initiated by a single-electron-transfer oxidizing process
(Chemical Equation Presented) Aromatic substitution: The treatment of diaryliodonium bromides 1 with aromatic nucleophiles 2, afforded a variety of heteroaryl-containing biaryls 3 in good yields. The ipso-substitution process at the heteroaryl ring in 1 occurs through the formation of aromatic cation radicals, which are initiated by the single-electron-transfer (SET) oxidation of 2. (HFIP = hexafluoroisopropanol)
Dohi, Toshifumi,Ito, Motoki,Yamaoka, Nobutaka,Morimoto, Koji,Fujioka, Hiromichi,Kita, Yasuyuki
supporting information; experimental part
p. 3334 - 3337
(2010/08/04)

Enhanced reactivity of [hydroxy(tosyloxy)iodo]benzene in fluoroalcohol media. Efficient direct synthesis of thienyl(aryl)iodonium salts
In this manuscript, we report clear evidence for the generation of aromatic cation radicals produced by using [hydroxy(tosyloxy)iodo]benzene (HTIB) in fluoroalcohol solvents such as 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP). The single-electron-transfer (SET) oxidation ability of HTIB to give cation radicals was first established by ESR and UV measurements. The reaction was broadly applied to various thiophenes, and unique thienyliodonium salts were directly synthesized by this method in excellent yields without the production of any harmful byproducts.
Ito, Motoki,Ogawa, Chieko,Yamaoka, Nobutaka,Fujioka, Hiromichi,Dohi, Toshifumi,Kita, Yasuyuki
experimental part
p. 1918 - 1931
(2010/09/08)

Layered double hydroxide-supported l-methionine-catalyzed chemoselective o-methylation of phenols and esterification of carboxylic acids with dimethyl carbonate: A "green" protocol
" Chemical equation presented" Simple methodology: A layered double hydroxide-supported L-methionine (LDH-Met) catalyst is designed in a simple methodology to explore its synthetic utility in biologically relevant reactions. The organocatalyst is characterized by FT-IR, TGA/DTA, powder XRD, and EDX spectroscopic techniques. This material has been successfully utilized for the preparation of aryl methyl ethers and esters from the corresponding phenols and carboxylic acids, respectively, in moderate to high yields (see scheme).
Dhakshinamoorthy, Amarajothi,Sharmila, Alagarsamy,Pitchumani, Kasi
supporting information; experimental part
p. 1128 - 1132
(2010/06/13)

METHODS AND COMPOSITIONS FOR CONTROL OF GYPSY MOTHS, Lymanria dispar
The invention provides in part dialkoxybenzene and eugenol compounds for controlling infestation by a Lymantria dispar, and methods thereof. The compounds include a compound of Formula I: where R1 may be methyl, ethyl, propyl, n-butyl, isopentyl (3-methylbutyl) or allyl; R2 may be at positions 2, 3 or 4 and may be H, methyl, ethyl, propyl, n-butyl, isopentyl (3-methylbutyl) or allyl; and R3 may be optionally present at positions 2, 3 and 4, and is allyl; with the provisos that when R2 is at position 2, R3 if present is at position 3, or when R2 is at to position 3, R3 if present is at positions 2 or 4, or when R2 is at position 4, R3 if present is at position 2; or of Formula II: where R1 may be methyl, ethyl, propyl, n-butyl, isopentyl (3-methylbutyl) or allyl; or mixtures thereof.
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(2010/08/07)