6407-55-2Relevant academic research and scientific papers
Synthesis of 1,4,5,16-tetrahydroxytetraphenylene
Hui, Chi Wai,Mak, Thomas C.W.,Wong, Henry N.C.
, p. 3523 - 3531 (2004)
This paper concerns the synthesis of 1,4,5,16-tetrahydroxytetraphenylene, which may function as a building block for the construction of molecular scaffolds. The synthesis of 1,4,5,16-tetrahydroxytetraphenylene was realized by stepwise Diels-Alder reactions to form two benzene rings using 1,10-dimethoxydibenzo[a,e]cyclooctene as a precursor. This key intermediate, in turn, could be obtained by photo-rearrangement of its corresponding barrelene.
Atoms-in-molecules analysis of extended hypervalent five-center, six-electron (5c-6e) C2Z2O interactions at the 1,8,9-positions of anthraquinone and 9-methoxyanthracene systems
Nakanishi, Waro,Nakamoto, Takashi,Hayashi, Satoko,Sasamori, Takahiro,Tokitoh, Norihiro
, p. 255 - 268 (2007)
To clarify the nature of five-center, six-electron (5c-6e) C 2Z2O interactions, atoms-in-molecules (AIM) analysis has been applied to an anthraquinone, 1,8-(MeZ)2ATQ (1 (Z = Se), 2 (Z = S), and 3 (Z = O)), and a 9-methoxyanthracene system, 9-MeO-1,8-(MeZ) 2ATC (4 (Z = Se), 5 (Z = S), and 6 (Z = O)), as well as 1-(MeZ)ATQ (7 (Z = Se), 8 (Z = S), and 9 (Z = O)) and 9-MeO-1-(MeZ)ATC (10 (Z = Se), 11 (Z = S), and 12 (Z = O)). The total electronic energy density (Hb(r c)) at the bond critical points (BCPs), an appropriate index for weak interactions, has been examined for 5c-6e C2Z2O and 3c-4e CZO interactions of the np(O)...σ*(Z-C) type in 1-12. Some hydrogen-bonded adducts were also re-examined for convenience of comparison. The total electronic energy densities varied in the following order: O...O (3: Hb(rc) = 0.0028 au) = O...O (6: 0.0028 au) > O...O (9: 0.0025 au) ≥ NN...HF (0.0024 au) ≥ O...O (12: 0.0023 au) ? H2O...HOH (0.0015 au) > S...O (8: 0.0013 au) = S...O (2: 0.0013 au) > S...O (11: 0.0012 au) = S...O (5: 0.0012 au) > HF...HF (0.0008 au) = Se...O (10: 0.0008 au) = Se...O (4: 0.0008 au) ≥ Se...O (1: 0.0007 au) ≥ Se...O (7: 0.0006 au) ? HCN...HF (-0.0013 au). Hb(rc) values for S...O were predicted to be smaller than the hydrogen bond of H2O...HOH and Hb(r c) values for Se...O are very close to or slightly smaller than that for HF...HF in both the ATQ and 9-MeOATC systems. In the case of Z = Se and S, Hb(rc) values for 5c-6e C2Z 2O interactions are essentially equal to those for 3c-4e CZO if Z is the same. The results demonstrate that two np(O) ...σ*(Z-C) 3c-4e interactions effectively connect through the central np(O) orbital to form the extended hypervalent 5c-6e system of the σ*(C-Z)-np(O)...σ* (Z-C) type for Z = Se and S in both systems. Natural bond orbital (NBO) analysis revealed that ns(O) also contributes to some extent. The electron charge densities at the BCPs, NBO analysis, and the total energies calculated for 1-12, together with the structural changes in the PhSe derivatives, support the above discussion.
Ionic Highways from Covalent Assembly in Highly Conducting and Stable Anion Exchange Membrane Fuel Cells
Kim, Yoonseob,Wang, Yanming,France-Lanord, Arthur,Wang, Yichong,Wu, You-Chi Mason,Lin, Sibo,Li, Yifan,Grossman, Jeffrey C.,Swager, Timothy M.
supporting information, p. 18152 - 18159 (2019/11/14)
A major challenge in the development of anion exchange membranes for fuel cells is the design and synthesis of highly stable (chemically and mechanically) conducting membranes. Membranes that can endure highly alkaline environments while rapidly transporting hydroxides are desired. Herein, we present a design using cross-linked polymer membranes containing ionic highways along charge-delocalized pyrazolium cations and homoconjugated triptycenes. These ionic highway membranes show improved performance. Specifically, a conductivity of 111.6 mS cm-1 at 80 °C was obtained with a low 7.9% water uptake and 0.91 mmol g-1 ion exchange capacity. In contrast to existing materials, ionic highways produce higher conductivities at reduced hydration and ionic exchange capacities. The membranes retain more than 75% of their initial conductivity after 30 days of an alkaline stability test. The formation of ionic highways for ion transport is confirmed by density functional theory and Monte Carlo studies. A single cell with platinum metal catalysts at 80 °C showed a high peak density of 0.73 W cm-2 (0.45 W cm-2 from a silver-based cathode) and stable performance throughout 400 h tests.
Ionic Highways from Covalent Assembly in Highly Conducting and Stable Anion Exchange Membrane Fuel Cells
Kim, Yoonseob,Wang, Yanming,France-Lanord, Arthur,Wang, Yichong,Wu, You-Chi Mason,Lin, Sibo,Li, Yifan,Grossman, Jeffrey C.,Swager, Timothy M.
supporting information, p. 18152 - 18159 (2019/11/28)
A major challenge in the development of anion exchange membranes for fuel cells is the design and synthesis of highly stable (chemically and mechanically) conducting membranes. Membranes that can endure highly alkaline environments while rapidly transporting hydroxides are desired. Herein, we present a design using cross-linked polymer membranes containing ionic highways along charge-delocalized pyrazolium cations and homoconjugated triptycenes. These ionic highway membranes show improved performance. Specifically, a conductivity of 111.6 mS cm-1 at 80 °C was obtained with a low 7.9% water uptake and 0.91 mmol g-1 ion exchange capacity. In contrast to existing materials, ionic highways produce higher conductivities at reduced hydration and ionic exchange capacities. The membranes retain more than 75% of their initial conductivity after 30 days of an alkaline stability test. The formation of ionic highways for ion transport is confirmed by density functional theory and Monte Carlo studies. A single cell with platinum metal catalysts at 80 °C showed a high peak density of 0.73 W cm-2 (0.45 W cm-2 from a silver-based cathode) and stable performance throughout 400 h tests.
A practical synthesis of 1,4,5,8-tetramethoxyanthracene from inexpensive and readily available 1,8-dihydroxyanthraquinone
Navale, Tushar S.,Rathore, Rajendra
experimental part, p. 805 - 809 (2012/04/10)
The preparation of gram quantities of 1,4,5,8-tetra-methoxyanthracene from commercially available and inexpensive 1,8-dihydroxyanthraquinone is described. The key steps in the synthesis involve bromination of 1,8-dimethoxyanthracene to form 1,8-dibromo-4,5-dimethoxyanthracene followed by Cu(I) catalyzed replacement of bromo substituents with methoxy groups. The contrasting reports concerning the preparation of 1,8-dimethoxy-anthracene from 1,8- dimethoxyanthraquinone using zinc dust in refluxing acetic acid are also discussed. Georg Thieme Verlag Stuttgart · New York.
Design and synthesis of a novel triptycene-based ligand for modeling carboxylate-bridged diiron enzyme active sites
Li, Yang,Cao, Rui,Lippard, Stephen J.
, p. 5052 - 5055 (2011/12/02)
A novel triptycene-based ligand with a preorganized framework was designed to model carboxylate-bridged diiron active sites in bacterial multicomponent monooxygenase (BMM) hydroxylase enzymes. The synthesis of the bis(benzoxazole)-appended ligand L1 depicted was accomplished in 11 steps. Reaction of L1 with iron(II) triflate and a carboxylate source afforded the desired diiron(II) complex [Fe2L1(μ-OH)-(μ-O 2CArTol)(OTf)2].
Synthesis, antiprolife ativeactivity and inhibition of tubulinpolymerization byanthracenone-based oxime derivatives
Surkau, Georg,B?hm, Konrad J.,Müller, Klaus,Prinz, Helge
scheme or table, p. 3354 - 3364 (2010/08/06)
A series of anthracenone-based oxime ethers and-esters were synthesized in order to evaluate their antiproliferative activity. Several investigated compounds displayed strong antiproliferative activity against K562 leukemia cells and proved to be strong inhibitors of tubulin polymerization. In this context,anthracenone-based oxime ethers and-esters are considered to contribute to the development of novel antiproliferative drugs,based on tubulin interaction.
Syntheses and structures of hypervalent pentacoordinate carbon and boron compounds bearing an anthracene skeleton - Elucidation of hypervalent interaction based on X-ray analysis and DFT calculation
Yamashita, Makoto,Yamamoto, Yohsuke,Akiba, Kin-Ya,Hashizume, Daisuke,Iwasaki, Fujiko,Takagi, Nozomi,Nagase, Shigeru
, p. 4354 - 4371 (2007/10/03)
Pentacoordinate and tetracoordinate carbon and boron compounds (27, 38, 50-52, 56-61) bearing an anthracene skeleton with two oxygen or nitrogen atoms at the 1,8-positions were synthesized by the use of four newly synthesized tridentate ligand precursors. Several carbon and boron compounds were characterized by X-ray crystallographic analysis, showing that compounds 27, 56-59 bearing an oxygen-donating anthracene skeleton had a trigonal bipyramidal (TBP) pentacoordinate structure with relatively long apical distances (ca. 2.38-2.46 A). Despite the relatively long apical distances, DFT calculation of carbon species 27 and boron species 56 and experimental accurate X-ray electron density distribution analysis of 56 supported the existence of the apical hypervalent bond even though the nature of the hypervalent interaction between the central carbon (or boron) and the donating oxygen atom was relatively weak and ionic. On the other hand, X-ray analysis of compounds 50-52 bearing a nitrogen-donating anthracene skeleton showed unsymmetrical tetracoordinate carbon or boron atom with coordination by only one of the two nitrogen-donating groups. It is interesting to note that, with an oxygen-donating skeleton, the compound 61 having two chlorine atoms on the central boron atom showed a tetracoordinate structure, although the corresponding compound 60 with two fluorine atoms showed a pentacoordinate structure. The B-O distances (av 2.29 A) in 60 were relatively short in comparison with those (av 2.44 A) in 59 having two methoxy groups on the central boron atom, indicating that the B-O interaction became stronger due to the electron-withdrawing nature of the fluorine atoms.
A New Convenient Synthesis of Alkoxyanthracenes from Alkoxy-9,10- anthraquinones
Lu, Lingang,Chen, Qiyin,Zhu, Xiaozhang,Chen, Chuanfeng
, p. 2464 - 2466 (2007/10/03)
Methoxy-9,10-anthraquinones with mono-, di- and tetraether groups at different positions 1a-h can be directly reduced to the corresponding methoxyanthracenes 3a-h in moderate to good yields by zinc in refluxing acetic acid. Under similar conditions, ethyl 1′-anthracenoxyacetate (3i) with the ester group unaffected and 1,8-oxybis(ethyleneoxyethyleneoxy)anthracene (5) were also conveniently synthesized in 65 and 70% yields, respectively.
Methylation of 1,8-dihydroxy-9,10-anthraquinone with and without use of solvent-free technique
Sereda, Grigoriy A.,Akhvlediani, David G.
, p. 9125 - 9126 (2007/10/03)
A convenient and environmentally friendly solvent-free procedure has been developed for dimethylation of 1,8-dihydroxy-9,10-anthraquinone with excellent yield. A highly selective monomethylation of 1,8-dihydroxy-9,10-anthraquinone in refluxing tetraglyme makes monomethylated peri-dihydroxy-9,10-anthraquinones easily available. Alternatively, irradiation in a domestic microwave oven has been employed for the solvent-free monomethylation of 1,8-dihydroxy-9,10-anthraquinone.
