- Geometry and steric effects on the electronic states of aryl-o-carboranes
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o-Carborane was used to alter the electronic states of π-conjugated organic aryls, and demonstrated as an effective electron control unit, to tune HOMO and LUMO energies for the electron transfer. Two different types of bis-aryl compounds were selected: one with di-phenyls and its fused fluorenyl, and another with two isomers of naphthyls, α- and β-forms. Among the series of aryl compounds, the second type of naphthyls were more susceptible to electronic alteration and α-isomer of naphthyl showed the most perturbed electronic state. The ground state structures confirmed by crystallographic measurements provide a close correlation of structure and electronic property between photo-responsive aryl groups and o-carborane. In addition to the distance effect, within similar proximity of the aryl functional groups, namely naphthyl case, the steric factor controlled the altered electronic state. HOMO and LUMO energies were estimated and confirmed by cyclic voltammograms and DFT calculations, respectively, and established the authenticity of the electronic alteration. Excited states were calculated by the TD-DFT correlations with the corresponding absorption spectra to illustrate the electronic perturbation in a systematic fashion suggesting that excited states were lowered in regard to the electronic perturbation. Therefore, within bis-aryls-o-carborane series, the following decreasing energy order is observed; α-Np, β-Np, Flu, diPh, and Ph. The final verification of the lowered energy was made according to the electron transfer efficiency between the well-studied iridium based photosensitizer, Ir(ppy)3 and two typical bis-aryls-o-carboranes, α-Np and Ph. The electron transfer efficiency of α-Np is 10 times greater than that of Ph (1.231 × 107 M?1s?1 for α-Np and 9.275 × 105 M?1s?1 for Ph).
- Kim, So-Yoen,Cho, Yang-Jin,Son, Ho-Jin,Kim, Chul Hoon,Kang, Sang Ook
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- Electrochemical B?H Nitrogenation: Access to Amino Acid and BODIPY-Labeled nido-Carboranes
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Electrocatalyzed oxidative B?H nitrogenations of nido-carborane (nido-7,8-C2B9H12?) with N-heterocycles have been established, enabling the preparation of various N-substituted nido-carboranes without chemical o
- Yang, Long,Bongsuiru Jei, Becky,Scheremetjew, Alexej,Kuniyil, Rositha,Ackermann, Lutz
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- Diamine monomer containing carborane structure, dianhydride monomer containing carborane structure and preparation method and application of diamine monomer and dianhydride monomer containing carborane structure
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The invention discloses a diamine monomer containing a carborane structure, a dianhydride monomer containing a carborane structure and a preparation method and application of the diamine monomer and the dianhydride monomer. The invention also discloses high-temperature-resistant polyimide containing the carborane structure. The polyimide is prepared by condensation polymerization of the diamine monomer containing the carborane structure and a dianhydride monomer containing the carborane structure. The preparation method comprises the following steps: taking decaborane and alkyne as initial raw materials, preparing a carborane structural unit through addition reaction of the decaborane and the alkyne, and then preparing the diamine monomer containing the carborane structure through nitration reaction and reduction reaction, or preparing the dianhydride monomer containing the carborane structure through oxidation and dehydrating reaction of methyl. The method for preparing the diamine monomer or dianhydride monomer containing the carborane structure has the advantages of simple operation, wide universality, convenient and easily available raw materials, high yield and the like, and is convenient for large-scale production.
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Paragraph 0058; 0143; 0145
(2021/07/21)
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- Metal-Free Oxidative B?N Coupling of nido-Carborane with N-Heterocycles
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A general method for the oxidative substitution of nido-carborane (7,8-C2B9H12?) with N-heterocycles has been developed by using 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) as an oxidant. This metal-free B?N coupling strategy, in both inter- and intramolecular fashions, gave rise to a wide array of charge-compensated, boron-substituted nido-carboranes in high yields (up to 97 %) with excellent functional-group tolerance under mild reaction conditions. The reaction mechanism was investigated by density-functional theory (DFT) calculations. A successive single-electron transfer (SET), B?H hydrogen-atom transfer (HAT), and nucleophilic attack pathway is proposed. This method provides a new approach to nitrogen-containing carboranes with potential applications in medicine and materials.
- Yang, Zhongming,Zhao, Weijia,Liu, Wei,Wei, Xing,Chen, Meng,Zhang, Xiao,Zhang, Xiaolei,Liang, Yong,Lu, Changsheng,Yan, Hong
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supporting information
p. 11886 - 11892
(2019/07/18)
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- Photoarylation of Iodocarboranes with Unactivated (Hetero)Arenes: Facile Synthesis of 1,2-[(Hetero)Aryl]n-o-Carboranes (n=1,2) and o-Carborane-Fused Cyclics
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Photoarylation of iodocarboranes with unactivated arenes/heteroarenes at room temperature has been achieved, for the first time, thus leading to the facile synthesis of a large variety of cage carbon mono(hetero)arylated and di(hetero)arylated o-carboranes. This work represents a clean, efficient, transition-metal-free, and cheap synthesis of functionalized carboranes, which has significant advantages over the known methods.
- Ni, Hangcheng,Qiu, Zaozao,Xie, Zuowei
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supporting information
p. 712 - 716
(2017/01/14)
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- Nickel-catalyzed cross-coupling reactions of o-carboranyl with aryl iodides: Facile synthesis of 1-aryl-o-carboranes and 1,2-diaryl-o-carboranes
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A nickel-catalyzed arylation at the carbon center of o-carborane cages has been developed, thus leading to the preparation of a series of 1-aryl-o-carboranes and 1,2-diaryl-o-carboranes in high yields upon isolation. This method represents the first examp
- Tang, Cen,Xie, Zuowei
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supporting information
p. 7662 - 7665
(2015/06/25)
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- High yielding synthesis of carboranes under mild reaction conditions using a homogeneous silver(I) catalyst: Direct evidence of a bimetallic intermediate
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Methods used to prepare functionalized carboranes generally require heating to high temperatures, and thus limits the range of derivatives which can be prepared directly from alkynes. We show here that by using a homogeneous silver(I) catalyst it is now possible to prepare carboranes in good to excellent yield at temperatures below 40 °C, including at room temperature. The process is general and provides an important new synthetic strategy for the preparation of functionalized boron clusters. Cluster around: Current methods to prepare carboranes require heating to high temperatures, thereby limiting the range of derivatives which can be prepared from functionalized alkynes. By using a AgI catalyst it is possible to prepare carboranes from substituted alkynes in good to excellent yields at temperatures below 40 °C, including room temperature. The approach provides an important new synthetic strategy for the preparation of functionalized boron clusters.
- El-Zaria, Mohamed E.,Keskar, Kunal,Genady, Afaf R.,Ioppolo, Joseph A.,McNulty, James,Valliant, John F.
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supporting information
p. 5156 - 5160
(2014/05/20)
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- Diaryl-substituted ortho-carboranes as a new class of hypoxia inducible factor-1α inhibitors
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Diaryl-substituted ortho-carboranes 1 were synthesized from the corresponding alkynes by decaborane coupling under microwave-irradiated conditions with a combination of N,N-dimethylaniline and chlorobenzene. Among the compounds synthesized, 1a and 1d exhibited significant inhibition of hypoxia-induced HIF-1 transcriptional activity. Both compounds similarly suppressed hypoxia-induced HIF-1α accumulation in a concentration- dependent manner without affecting HIF-1α mRNA expression.
- Nakamura, Hiroyuki,Tasaki, Lisa,Kanoh, Daisuke,Sato, Shinichi,Ban, Hyun Seung
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supporting information
p. 4941 - 4944
(2014/04/03)
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- O-carborane-based biphenyl and p-terphenyl derivatives
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The synthesis and properties of biphenyl- and p-terphenyl-fused o-carboranes are described. Aryl rings in the biphenyl and p-terphenyl skeletons are highly coplanar because of the presence of the o-carborane unit. o-Carborane exhibits an electron-withdrawing character via the inductive effect, resulting in a decrease in both the HOMO and LUMO levels of oligophenyls without causing electronic perturbation. To be free from perturbations: The synthesis and properties of biphenyl- and p-terphenyl-fused o-carboranes are described. Aryl rings in the biphenyl and p-terphenyl skeletons are highly coplanar because of the presence of the o-carborane unit. o-Carborane exhibits an electron-withdrawing character via the inductive effect, resulting in a decrease in both the HOMO and LUMO levels of oligophenyls without causing electronic perturbation.
- Morisaki, Yasuhiro,Tominaga, Masato,Ochiai, Takuya,Chujo, Yoshiki
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supporting information
p. 1247 - 1251
(2014/05/06)
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- High yielding preparation of dicarba-closo-dodecaboranes using a silver(I) mediated dehydrogenative alkyne-insertion reaction
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The synthesis of 1,2-dicarba-closo-dodecaboranes (ortho-carboranes) is often low yielding which is a critical issue given the increasing use of boron clusters in material science and medicinal chemistry. To address this barrier, a series of Cu, Ag, and Au salts were screened to identify compounds that would enhance the yields of ortho-caboranes produced when treating alkynes with B 10H12(CH3CN)2. Using a variety of functionalized ligands including mono- and polyfunctional internal and terminal alkynes, significant increases in yield were observed when AgNO3 was used in catalytic amounts. AgNO3 appears to prevent unwanted reduction/hydroboration of the alkyne prior to carborane formation, and the process is compatible with aryl, halo, hydroxy, nitrile, carbamate, and carbonyl functionalized alkynes.
- Toppino, Antonio,Genady, Afaf R.,El-Zaria, Mohamed E.,Reeve, James,Mostofian, Fargol,Kent, Jeff,Valliant, John F.
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supporting information
p. 8743 - 8749
(2013/09/02)
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