- Palladium nanoparticles-decorated graphene nanosheets as highly regioselective catalyst for cyclotrimerization reaction
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Novel palladium nanoparticles/graphene-based composites were prepared by a method involving palladium nanoparticles in situ growth on chitosan- functionalized graphene. The resulted composites showed uniform palladium nanoparticles distribution, which were characterized by Fourier transform infrared spectrometry (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy, atomic force microscopy (AFM), X-ray diffraction spectroscopy (XRD) and electron diffraction pattern (ED), etc. Moreover, such graphene-based nanocomposites were successfully applied to catalyze the cyclotrimerization of acetylene with high regioselectivity (=99.5%) and superior recycling performance without the assistance of any ligands. Copyright
- Cheng, Jinsheng,Tang, Longhua,Li, Jinghong
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- Switching of Adsorption Properties in a Zwitterionic Metal-Organic Framework Triggered by Photogenerated Radical Triplets
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A new metal-organic framework (MOF) that features photoreactive zwitterionic pyridinium 4-carboxylate units has been designed. Upon UV light irradiation, these units form radical triplets permitted by intramolecular electron transfer between anionic carbo
- An, Wen,Aulakh, Darpandeep,Zhang, Xuan,Verdegaal, Wolfgang,Dunbar, Kim R.,Wriedt, Mario
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- Octupolar organometallic Pt(II) NCN-pincer complexes; Synthesis, electronic, photophysical, and NLO properties
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A series of organometallic octupolar 1,3,5-substituted-2,4,6-styryl-benzene complexes was synthesized by post-modification of parent [PtCl(NCN-CHO-4)], i.e. 1,3,5-tri-R-2,4,6-tris[(4-(PtCl)(3,5-bis[(dimethylamino)methyl]styryl)]benzene (NCN = [C6H2(CH2NMe2)2-2,6]– in which R = OMe, H, Br (1–3). Their synthesis involved a triple Horner-Wadsworth-Emmons reaction of [PtCl(NCN-CHO-4)] with the appropriate tris[(diethoxyphosphoryl)]methyl]benzene derivative. The 195Pt{1H} NMR chemical shift reflects the electronic properties of the π-system to which it is connected. The UV/Vis bands of the octupolar platinum complexes are only slightly red-shifted (by 5–12 nm) with respect to those of corresponding stilbenoid Pt-Cl pincer compounds (i.e., the separate branches), suggesting that there is only a limited electronic interaction between these branches. The fluorescence Stokes shift, quantum yields and lifetimes of 1–3 also are of the same order of magnitude as those of stilbenoid Pt-Cl pincer compounds, indicating that a dipolar excited state is formed, which is localized on one of the three branches. The hyper-Rayleigh scattering technique revealed hyperpolarizabilites βHRS of 430, 870 and 183 × 10?30 esu for 1, 2 and 3, respectively, which are among the highest for transition metal complexes. The highest value was found for the compound lacking a donor or acceptor group at the central core, lending support to the idea that dispersion overwhelms charge transfer in determining the magnitude of the first hyperpolarizability in octupolar compounds.
- Batema, Guido D.,van Walree, Cornelis A.,van Klink, Gerard P.M.,de Mello Donegá, Celso,Meijerink, Andries,Perez-Moreno, Javier,Clays, Koen,van Koten, Gerard
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- New planar and soluble tris-tetrathiafulvalene derivatives with threefold-symmetry
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Novel trimeric tetrathiafulvalene (TTF) derivatives with threefold- symmetry are built on the 1,3,5-benzene core. Long alkyl chains have been incorporated on the peripheral positions of the TTF moieties in order to increase the solubility of the final products. Electrochemical and spectroscopic studies of the target compounds suggest that there are no significant interactions between the TTF units because of their meta orientation. Semiempirical theoretical calculations indicate that the new systems exhibit a high structural anisotropy resembling that exhibited by discotic liquid crystals. (C) 2000 Elsevier Science Ltd.
- González, Alfonso,Segura, José L.,Martín, Nazario
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- Control of the optical properties of a star copolymer with a hyperbranched conjugated polymer core and poly(ethylene glycol) arms by self-assembly
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A self-assembly approach to tuning the optical properties of a star copolymer is reported herein. The star copolymer HCP-star-PEG with a hyperbranched conjugated polymer (HCP) core and many linear poly(ethylene glycol) (PEG) arms has been prepared successfully. The HCP core was synthesized by Wittig coupling of N-(n-hexyl)-3,6-diformylcarbazole and 1,3,5- bis[(triphenylphosphonio)methyl]benzene tribromide. Subsequently, the linear PEG arms were grafted onto the HCP core by acylhydrazone connection. It was found that the optical properties of HCP-star-PEG in chloroform solution changed on addition of acid. Both 1H NMR and UV/Vis spectroscopic investigations confirmed that the variation of the optical properties was related to the complexation of the acid and the imine bond in the acylhydrazone group. HCP-star-PEG self-assembled into core-shell micelles in the mixed solvent of chloroform and acetonitrile, which affected the protonation of the imine bond. Therefore the optical properties of HCP-star-PEG can be readily controlled by self-assembly. Tuning a star copolymer: A star copolymer (HCP-star-PEG) with a hyperbranched conjugated (HCP) core and many poly(ethylene glycol) (PEG) arms has been synthesized through an acylhydrazone connection. The optical properties of HCP-star-PEG changed on complexation of acid (see figure). With different proportions of chloroform and acetonitrile, the optical properties of HCP-star-PEG can be easily controlled by self-assembly of the star polymer.
- Qiu, Feng,Tu, Chunlai,Chen, Yan,Shi, Yunfeng,Song, Liang,Wang, Ruibing,Zhu, Xinyuan,Zhu, Bangshang,Yan, Deyue,Han, Tao
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- Twisted baskets
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A preparative procedure for obtaining a pair of twisted molecular baskets, each comprising a chiral framework with either right ((P)-1syn) or left ((M)-1syn) sense of twist and six ester groups at the rim has been developed and optim
- Hermann, Keith,Pratumyot, Yaowalak,Polen, Shane,Hardin, Alex M.,Dalkilic, Erdin,Dastan, Arif,Badji?, Jovica D.
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- Synthesis of tris(β-diketones) and study of their complexation with some transition metals
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New chelating ligands consisting of three β-diketone fragments, viz., 1,3,5-tris[(acetylaceton-3-yl)methyl]benzene, 1,3,5-tris[(benzoylaceton-3-yl) methyl]benzene, and 1,3,5-tris[(dibenzoylmethan-1-yl)methyl]benzene, linked to each other through the mesit
- Podyachev,Sudakova,Galiev,Mustafina,Syakaev,Shagidullin,Bauer,Konovalov
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- A facile synthesis of microporous organic polymers for efficient gas storage and separation
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A series of porous hyper-cross-linked polymers with excellent physiochemical stability have been designed and prepared facilely through template-free Friedel-Crafts alkylation reactions between benzene/biphenyl/1,3,5-triphenylbenzene as co-condensing rigid aromatic building blocks and 1,3,5-tris(bromomethyl)benzene or 1,3,5-tris(bromomethyl)-2,4,6-trimethylbenzene as cross-linkers under the catalysis of anhydrous AlCl3 or FeCl3. The systematic study of gas uptake ability shows that anhydrous AlCl3 is a much more effective catalyst than anhydrous FeCl3. The synthesized polymers are thermally stable and are predominantly microporous with high surface areas up to 1783 m2 g-1. In addition, they exhibit high H2 and CO2 uptake capacity/selectivity. Among these materials, C1M3-Al has the highest H2 uptake capacity at 77 K and 1 bar (19.1 mg g-1) and CO2 uptake capacity at 273 K and 1 bar (181 mg g-1); the best CO2/N2 (15/85) selectivity calculated by IAST at 273 K and 1 bar belongs to C1M2-Al (32.3). Moreover, the synthesis route exhibits cost-effective advantages, which are essential for scale-up preparation, thus showing great potential for clean energy applications.
- Liu, Guoliang,Wang, Yangxin,Shen, Chaojun,Ju, Zhanfeng,Yuan, Daqiang
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- Synthesis and analysis of in vitro anti-arthritic activity of dendrimers with methyl, ethyl and isopropyl salicylates as surface groups
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Frchet type dendrimers with salicylates as surface groups have been synthesized using the divergent approach and their in vitro anti-arthritic activity was analyzed by inhibition of protein denaturation.
- Jayanthi, Mani,Rajakumar, Perumal
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- Synthesis and photoluminescent properties of four novel trinuclear europium complexes based on two tris-β-diketones ligands
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Four novel trinuclear europium complexes with two tris-β-diketones ligands have been synthesized, and the chemical structures of ligands and complexes were characterized by FT-IR, UV-vis, 1H NMR, 13C NMR, XRD, ESI-MS, and element analysis. The potoluminescent properties of trinuclear complexes in solid and THF solution were investigated. All trinuclear complexes exhibited strong relative luminescent intensity and long luminescent lifetime. Meanwhile, the results of lifetime decay curves indicated that only one chemical environment existed around the europium ion. The intrinsic luminescent quantum yields (ΦLN) and experimental intensity parameters of trinuclear complexes were obtained based on the emission spectra and luminescent lifetime of 5D0 excited state for europium ion. All trinuclear europium complexes exhibited relative high intrinsic luminescent yield and intensity parameters. Especially, due to the contribution of addition two europium lumophors in trinuclear europium complexes, the trinuclear complexes containing TTA exhibited much longer lifetime and higher intrinsic quantum yield than mononuclear europium complex Eu(TTA) 3phen.
- Yang, Chaolong,Luo, Jianxin,Ma, Jianying,Lu, Mangeng,Liang, Liyan,Tong, Bihai
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- Synthesis of bis- and tris(indolinylidenemethyl)benzenes by one-pot reactions of polylithiated nitriles with bis(imidoyl)chlorides of oxalic acid
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The reaction of polylithiated di- and tricyanomethylbenzenes with oxalic acid-bis(imidoyl)chlorides afforded novel oligo(indolinylidenemethyl)benzenes with the formation of up to six carbon-carbon bonds. The UV/Vis spectroscopic features of these and related compounds were studied. 1,4-Disubstituted benzenes containing a large π-system have been efficiently prepared by the reaction of dianions with 1,4-dicyanobenzene. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
- Langer, Peter,Anders, Joachim T.
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- Aromatic Linkers Unleash the Antiproliferative Potential of 3-Chloropiperidines Against Pancreatic Cancer Cells
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In this study, we describe the synthesis and biological evaluation of a set of bis-3-chloropiperidines (B?CePs) containing rigid aromatic linker structures. A modification of the synthetic strategy also enabled the synthesis of a pilot tris-3-chloropiperidine (Tri-CeP) bearing three reactive meta-chloropiperidine moieties on the aromatic scaffold. A structure–reactivity relationship analysis of B?CePs suggests that the arrangement of the reactive units affects the DNA alkylating activity, while also revealing correlations between the electron density of the aromatic system and the reactivity with biologically relevant nucleophiles, both on isolated DNA and in cancer cells. Interestingly, all aromatic 3-chloropiperidines exhibited a marked cytotoxicity and tropism for 2D and 3D cultures of pancreatic cancer cells. Therefore, the new aromatic 3-chloropiperidines appear to be promising contenders for further development of mustard-based anticancer agents aimed at pancreatic cancers.
- Helbing, Tim,Carraro, Caterina,Francke, Alexander,Sosic, Alice,De Franco, Michele,Gandin, Valentina,G?ttlich, Richard,Gatto, Barbara
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p. 2040 - 2051
(2020/09/21)
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- Azine-based polymers with a two-electron redox process as cathode materials for organic batteries
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There is a growing interest in organic-based cathode materials for batteries due to their higher sustainability, low toxicity and energy-efficient production and recycling. Organic p-type compounds that undergo two reversible oxidations are relatively rar
- Acker, Pascal,Speer, Martin E.,W?ssner, Jan S.,Esser, Birgit
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p. 11195 - 11201
(2020/06/17)
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- A novel nitrogen heterocyclic ligand-based MOF: Synthesis, characterization and photocatalytic properties
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A coordination polymer, {[Co(tib)2]·SO4}n, has been synthesized by a solvothermal reaction using the flexible tripodal ligand 1,3,5-tris(imidazol-1-ylmethyl)benzene (TIB) with metal salts, and has been characterized by Fou
- Shang, Qigao,Zeng, Tianyu,Gao, Ke,Liu, Nannan,Cheng, Qingrong,Liao, Guiying,Pan, Zhiquan,Zhou, Hong
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supporting information
p. 16595 - 16603
(2019/11/11)
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- Dendritic architectures by orthogonal thiol-maleimide "click" and furan-maleimide dynamic covalent chemistries
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A set of dendrons and dendrimers is synthesized divergently using an orthogonal combination of kinetically-driven thiol-maleimide "click" chemistry and thermodynamically reversible furan-maleimide cycloaddition/retrocycloaddition reactions. Growth is controlled by taking advantage of the selective thiol-ene addition of thiols to the electron withdrawn alkene of maleimide in the presence of electron rich alkene of oxanorbornene. Subsequent activation of growing dendrons/dendrimers requires only heat to induce the dynamic covalent liberation of peripheral furan protecting groups. The methodology introduced provides a new route to multifunctional dendrimers that could, in principle, be synthesized by introducing different branched monomers at any stage of dendrimer growth, allowing dendrimer architectures and properties to be better tailored to their intended applications.
- Frayne, Stephen H.,Stolz, Robert M.,Northrop, Brian H.
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supporting information
p. 7878 - 7883
(2019/09/06)
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- Shape-Persistent [4+4] Imine Cages with a Truncated Tetrahedral Geometry
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The synthesis of shape-persistent organic cage compounds is often based on the usage of multiple dynamic covalent bond formation (such as imines) of readily available precursors. By careful choice of the precursors geometry, the geometry and size of the resulting cage can be accurately designed and indeed a number of different geometries and sizes have been realized to date. Despite of this fact, little is known about the precursors conformational rigidity and steric preorganization of reacting functional groups on the outcome of the reaction. Herein, the influence of conformational rigidity in the precursors on the formation of a [4+4] imine cage with truncated tetrahedral geometry is discussed.
- Lauer, Jochen C.,Zhang, Wen-Shan,Rominger, Frank,Schr?der, Rasmus R.,Mastalerz, Michael
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p. 1816 - 1820
(2018/01/22)
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- Structural examination of halogen-bonded co-crystals of tritopic acceptors
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A series of tritopic N-heterocyclic compounds containing electrostatically and geometrically equivalent binding sites were synthesized and subjected to systematic co-crystallizations with selected perfluoroiodoarenes in order to map out their structural landscapes. More than 70% of the attempted reactions produced a co-crystal as indicated by IR spectroscopy. Four new crystal structures are reported and in all of them, at least one potential binding site on the acceptor is left vacant. The absence of halogen bonds to all sites can be ascribed primarily due to deactivation of the σ-hole on the iodo-arene donors and partially due to steric hindrance. The tritopic acceptors containing 5,6-dimethylbenzimidazole derivatives yield discrete tetrameric aggregates in the solid state, whereas the pyrazole and imidazole analogues assemble into halogen-bonded 1-D chains.
- Andree, Stefan N. L.,Sinha, Abhijeet S.,Aaker y, Christer B.
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- Molecular electrostatic potentials as a quantitative measure of hydrogen bonding preferences in solution
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An easily accessible methodology for estimating hydrogen-bond preferences and binding affinities in solution, based on molecular electrostatic potential surfaces (MEPS), is presented. Isothermal titration calorimetry (ITC) data provide a quantitative meas
- Andree, Stefan N. L.,Aaker?y, Christer B.
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p. 455 - 463
(2018/01/03)
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- Potent anti-proliferative activities of organochalcogenocyanates towards breast cancer
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The pharmacological importance, particularly the anti-cancer and chemopreventive potentials, of organochalcogen compounds has attracted wide research attention recently. Herein we describe the synthesis of a series of organochalcogenocyanates that have one or more selenocyanate or thiocyanate units in a single molecule. The anti-proliferative activity of these organochalcogenocyanates in different breast cancer cells shows that selenocyanates exhibit much higher anti-proliferative activities than thiocyanates in general. Our study reveals that the activity of benzyl selenocyanate (1, BSC) could be significantly enhanced by 4-nitro substitution (12), which was more selective towards triple-negative breast cancer cells (MDA-MB-231) over other ER+ breast cancer cells (MCF-7 and T-47D). Furthermore, to the best of our knowledge, this is the first report on the synthesis of compounds having more than two selenocyanate units with promising anti-proliferative activities. Our studies further indicate that the apoptotic activities of selenocyanates are associated with modulation of cellular morphology and cell cycle arrest at S-phase. Selenocyanates also inhibited cellular migration and exhibited weak antioxidant activities. An effective binding interaction of compound 12 with serum albumin indicates its feasible transport in the bloodstream for its enhanced anti-cancer properties. Mechanistic studies by western blot analysis demonstrate that benzylic selenocyanates exhibit anti-proliferative activities by modulating key cellular proteins such as Survivin, Bcl-2 and COX-2; this was further supported by molecular docking studies. The results of this study would be helpful in designing suitable chemotherapeutic and chemopreventive drugs in the future.
- Banerjee, Kaustav,Padmavathi, Ganesan,Bhattacherjee, Debojit,Saha, Suchismita,Kunnumakkara, Ajaikumar B.,Bhabak, Krishna P.
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supporting information
p. 8769 - 8782
(2018/11/30)
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- Exploiting Peptidomimetics to Synthesize Compounds That Activate Ryanodine Receptor Calcium Release Channels
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Ryanodine receptor (RyR) Ca2+-release channels are essential for contraction in skeletal and cardiac muscle and are prime targets for modification of contraction in disorders that affect either the skeletal or heart musculature. We designed and synthesized a number of compounds with structures based on a naturally occurring peptide (A peptides) that modifies the activity of RyRs. In total, 34 compounds belonging to eight different classes were prepared. The compounds were screened for their ability to enhance Ca2+ release from isolated cardiac sarcoplasmic reticulum (SR) vesicles, with 25 displaying enhanced Ca2+ release. Competition studies with the parent peptides indicated that the synthetic compounds act at a competing site. The activity of the most effective of the compounds, BIT 180, was further explored using Ca2+ release from skeletal SR vesicles and contraction in intact skeletal muscle fibers. The compounds did not alter tension in intact fibers, indicating that (as expected) they are not membrane permeable, but importantly, that they are not toxic to the intact cells. Proof in principal that the compounds would be effective in intact muscle fibers if rendered membrane permeable was obtained with a structurally related membrane-permeable scorpion toxin (imperatoxin A), which was found to enhance contraction.
- Robinson, Ken,Easton, Christopher J.,Dulhunty, Angela F.,Casarotto, Marco G.
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p. 1957 - 1971
(2018/09/11)
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- Synthesis of dendrimer-type viologen and its use in Pd-mediated homocoupling of aryl halides
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Dendrimer-type viologen (V2+.D.) was prepared from mesitylene and 4.4′-bipyridyl. Electroreduction of V2+.D. gave the corresponding quinoid (V0.D.), which promoted Pd-catalyzed homocoupling of aryl bromides Ar-Br to give the corresponding biaryls Ar-Ar in moderate to good yields.
- Kuroboshi, Manabu,Kojima, Atsuki,Tanaka, Hideo
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p. 2132 - 2140
(2017/11/21)
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- Synthetic study and structure of cage-type cyclophane C36H36S6
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A cage compound was synthesized in order to investigate the structure and cation-π interactions of the metal ion complex. The multi-step synthesis was achieved starting from trimesic acid triethyl ester. In solution, a completely symmetrical structure that was anticipated by the molecular design was observed by 1H and 13C NMR spectroscopy. However, in the solid state, X-ray crystallographic analysis revealed that the compound had a collapsed structure.
- Takemura, Hiroyuki,Nagaoka, Maiko,Kawasaki, Chihiro,Tokumoto, Kasumi,Tobita, Noriko,Takano, Yuki,Iwanaga, Tetsuo
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p. 1066 - 1070
(2017/03/31)
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- New quaternary phosphonium salt as multi-site phase-transfer catalyst for various alkylation reactions
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The present work describes the C-alkylation reactions of fluorene and curcumin catalyzed by a new phosphonium salt, benzene-1,3,5-triyltris(methylene))tris(triphenylphosphonium)bromide, as a multi-site phase-transfer catalyst (MPTC). The catalytic efficie
- Ponmuthu, Kottala Vijaya,Kumaraguru, Duraimurugan,Arockiam, Jesin Beneto,Velu, Sadhasivam,Sepperumal, Murugesan,Ayyanar, Siva
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p. 8345 - 8358
(2016/11/25)
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- Tripodal Tris- N -oxides: Synthesis and Hydrogen Bonding Capabilities
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A number of tripodal tris-N-oxide receptors were synthesized and their hydrogen-bonding capabilities were investigated. Particular success was seen with both the benzene- and mesitylene-linked trismorpholine N-oxide receptors, which exhibited significant hydrogen bonding to both water and urea, as well as the inclusion of a rare decameric water cluster, as demonstrated by X-ray crystallography.
- Nixon, Gemma L.,Billington, Helen,Kalindjian, S. Barret,Steiner, Alexander,O'Neil, Ian A.
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supporting information
p. 141 - 145
(2015/12/26)
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- Synthesis of C3-symmetric tri(alkylamino) guests and their interaction with cyclodextrins
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The synthesis of a series of star-shaped C3-symmetric amines and their inclusion complexation properties toward α-, β-, γ-cyclodextrins and their permethylated derivatives has been described. The star molecules comprise of 1, 3, 5-trisubstited benzene core and the points formed by (alkylamino)methyl or 4-((alkylamino)methyl)phenyl groups. The modes of host-guest interaction were studied by UV-Vis spectroscopy, ITC, 1H NMR and 2D-NMR (NOESY). It was found that star molecules containing (tert-butylamino)methyl, (adamantan-1-ylamino)methyl, 4-((isopropylamino)methyl) phenyl, 4-((tert-butylamino)methyl)phenyl and protonated 4-((adamantan-1-ylamino)methyl)phenyl points form strong host-guest complexes with β-cyclodextrin. It was also proved that the largest C3-symmetric guest can form complexes with bcyclodextrin with stoichiometry 3 which is required for construction of dendrimer supramolecular structures. None of the investigated amines forms a strong complex with permethylated cyclodextrins.
- Bedna?íková, Tereza,Tosňer, Zdeněk,Horsky, Ji?í,Jind?ich, Jind?ich
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p. 141 - 152
(2015/04/22)
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- Highly enantioselective Michael addition reactions with new trimeric chiral phase transfer catalysts
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New types of mesitylene based tri-site containing asymmetric quaternary ammonium salts 9a and 9b have been prepared and used as efficient chiral phase transfer catalysts for enantioselective Michael addition reactions between the chalcones and diethylmalonate under mild reaction conditions such as lower concentration of base, catalyst and ultrasonic conditions with very good chemical yields (up to 98%) and ee's (up to 99%).
- Beneto, Arockiam Jesin,Sivamani, Jayaraman,Ashokkumar, Veeramanoharan,Balasaravanan, Rajendiran,Duraimurugan, Kumaraguru,Siva, Ayyanar
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p. 3098 - 3104
(2015/04/14)
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- Synthesis and thermal stability of new polynitrostilbenes
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New polynitrostilbenes were directly synthesised by the Knoevenagel condensation of aromatic aldehydes with nitrotoluenes. The differential scanning calorimetry results demonstrated that the introduction of an amino group and C≤C double bonds could improve the thermal stability.
- Wei, Jianping,Li, Fangmei,Xu, Junhui,Peng, Xinhua
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p. 919 - 925
(2015/06/25)
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- Rationally designed cooperatively enhanced receptors to magnify host-guest binding in water
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When disengaged interactions within a receptor are turned on by its guest, these intrahost interactions will contribute to the overall binding energy. Although such receptors are common in biology, their synthetic mimics are rare and difficult to design. By engineering conflictory requirements between intrareceptor electrostatic and hydrophobic interactions, we enabled complementary guests to eliminate the "electrostatic frustration" within the host and turn on the intrahost interactions. The result was a binding constant of Ka >105 M-1 from ammonium-carboxylate salt bridges that typically function poorly in water. These cooperatively enhanced receptors displayed excellent selectivity in binding, despite a large degree of conformational flexibility in the structure.
- Gunasekara, Roshan W.,Zhao, Yan
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supporting information
p. 843 - 849
(2015/01/30)
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- Synthesis and properties of poly(p-phenylene vinylene) derivatives with hyperbranched structure and containing a nitro substituent
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In order to improve efficiency, processability, and stability, two groups of novel poly(p-phenylene vinylene) (PPV) derivatives (P1-P 3 and P4-P6) with hyperbranched structure and containing a nitro substituent were synthesized via a Gilch reaction in different monomer ratios. The properties of the polymers were investigated by using UV-Vis absorption, fluorescence spectroscopy, cyclic voltammetry, and thermogravimetric analysis. The result shows that the band gaps of the PPV derivatives with a nitro substituent were decreased and the polymers had higher molecular weights (106), excellent solubility in common organic solvents, good film-forming ability, and better thermal stability. The polymers can be used as an efficient acceptor material in polymeric solar cells. Graphical abstract: [Figure not available: see fulltext.]
- Li, Ruyu,Mo, Yanjiao,Shi, Rong,Li, Peng,Li, Chengyu,Wang, Zhenjiang,Wang, Xun,Li, Shengbiao
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- Enhanced fluorescence of silver nanoclusters stabilized with branched oligonucleotides
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DNA stabilized silver nanoclusters (AgNCs) are promising optical materials, whose fluorescence properties can be tuned by the selection of the DNA sequence employed. In this work we have used modified oligonucleotides in the preparation of AgNCs. The fluorescent intensity obtained was 60 times higher than that achieved with standard oligonucleotides. The Royal Society of Chemistry.
- Latorre, Alfonso,Lorca, Romina,Zamora, Felix,Somoza, Alvaro
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p. 4950 - 4952
(2013/06/26)
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- A new selective turn-on fluorogenic dipodal-cobalt(II) ensemble probe for nitrite ion detection and live cell imaging
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A new dipodal-triazole-Co2+-ensemble with a ligand containing quinoline moiety was designed and synthesized as a highly sensitive fluorescent sensor for nitrite in aqueous media. Based on in situ-formed Co2+-DTQ (Co2+ chelated dipodal of triazole-quinoline) ensembles having the specific binding affinity for nitrite anions over other anions, this sensory system allows rapid recognition and quantitative detection of nitrite in neutral aqueous media in an 'off-on' fashion. To confirm the suitability of DTQ for biological applications, we also employed it for the fluorescence detection of the changes of intracellular NO2- in three different species of cultured cells in the presence of nitrite ions.
- Mahapatra, Ajit Kumar,Hazra, Giridhari,Mukhopadhyay, Subhra Kanti,Mukhopadhyay, Anindita Roy
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p. 1164 - 1168
(2013/04/10)
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- HIV-1 X4 activities of polycationic Viologen based dendrimers by interaction with the chemokine receptor CXCR4: Study of structure-activity relationship
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A series of viologen based dendrimers with polycationic scaffold carrying 10, 18, 26, 42, and 90 charges per molecule were used to determine the structure-activity relationship (SAR) with regard to HIV-1 inhibitory activity. The studies involved five comp
- Asaftei, Simona,Huskens, Dana,Schols, Dominique
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supporting information
p. 10405 - 10413
(2013/02/23)
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- Multi-electron donor organic molecules containing hydroquinone methyl-ether as redox active units
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Three hydroquinone dimethyl ether derivatives have been synthesized and characterized by X-ray diffraction. The electron donating properties were evaluated by using UV-vis spectroscopy, cyclic voltammetry and by ESR spectroscopy. The microcrystalline cation-radical salts of the three donor molecules were also isolated by using antimony pentachloride, a single electron Lewis acid oxidant.
- Khandelwal, Manish,Hwang, In-Chul,Nair, Prakash Chandran R.,Lee, Jung-Woo
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experimental part
p. 1190 - 1198
(2012/07/14)
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- An acid-catalyzed cyclialkylation that provides rapid access to a twisted molecular basket
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Twist of fate: Expanding the scope of cavity-containing compounds is essential for developing more efficient sensors and catalysts. This report describes an efficient cyclialkylation reaction that provides rapid access to a novel C3 symmetric a
- Hermann, Keith,Turner, Daniel A.,Hadad, Christopher M.,Badjic, Jovica D.
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supporting information; experimental part
p. 8301 - 8305
(2012/08/14)
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- Generation of (nonafluoro-tert-butoxy)methyl ponytails for enhanced fluorous partition of aromatics and heterocycles
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The reaction of sodium perfluoro-tert-butoxide with benzylic carbon-bromide bond(s) leads to the formation of (nonafluoro-tert-butoxy)methyl ponytail(s), which can enhance the fluorous solubility and partition of aromatics and heterocycles.
- Zhao, Xi,Ng, Wing Yan,Lau, Kai-Chung,Collis, Alana E. C.,Horvath, Istvan T.
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experimental part
p. 3909 - 3914
(2012/06/30)
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- One-pot click synthesis of 1N-alkyl-4-aryl-1,2,3-triazoles from protected arylalkynes and alkyl bromides
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1N-Alkyl-4-aryl-1,2,3-triazoles have been prepared through a multicomponent one-pot protocol from the corresponding (arylethynyl)trimethylsilanes and alkyl bromides. In situ alkyl azide formation and alkyne deprotection followed by copper(I)-catalyzed click cycloaddition afforded the desired 1,4-disubstituted 1,2,3-triazoles in generally good to excellent yield, with only minor observation of the undesired 1,5-regioisomeric cycloadduct. The protocol eliminates the need to use reactive organic azides and terminal alkynes. Georg Thieme Verlag Stuttgart. New York.
- Ladouceur, Sebastien,Soliman, Ahmed M.,Zysman-Colman, Eli
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p. 3604 - 3611
(2011/12/16)
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- Fluorous silica gel-supported perfluoro-tagged palladium nanoparticles: An efficient and reusable catalyst for direct C-2 arylation of indoles
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The preparation of FSG-supported palladium nanoparticles and their application in direct C-2 arylation of indoles are presented. Moderate to good yields were obtained with ultra-low catalyst loading. The catalyst could be easily recovered by simple workup and reused up to seven runs with only a slight decrease in its activity. The Royal Society of Chemistry 2011.
- Wang, Liang,Yi, Wen-Bin,Cai, Chun
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supporting information; experimental part
p. 806 - 808
(2011/04/15)
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- Viologen-based benzylic dendrimers: selective synthesis of 3,5-bis(hydroxymethyl)benzylbromide and conformational analysis of the corresponding viologen dendrimer subunit
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Convergent and divergent strategies for the synthesis of viologen dendrimers with 1,3,5-tri-methylene-branching units are discussed. The title compound is easily transformed into 1-[3,5-bis(hydroxymethyl)benzyl]-4-(pyridin-4-yl)pyridinium hexafluorophosphate, which is used in sequential growth and activation steps as a CB2 compound in the cascade-type dendrimer synthesis (B = -OH, activation = -OH → Br). Analysis of the dendrimer structure reveals that three torsional angles, that is, τ1 between the two pyridinium units, τ2 between the methylene and pyridinium and τ3 between the methylene and phenyl, determine the conformational space of the dendrimers. We report here the crystal structure of 1-[3,5-bis(hydroxymethyl)benzyl]-4-(pyridin-4-yl)pyridinium as PF6- salt which represents the smallest subunit of the dendrimer that shows the same three torsional angles. The crystal structure together with the results from PM3 calculations opens an avenue to judge the structure of benzylic viologen-based dendrimers.
- Kathiresan, Murugavel,Walder, Lorenz,Ye, Fei,Reuter, Hans
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supporting information; experimental part
p. 2188 - 2192
(2010/06/19)
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- "viologen"dendrimers as antiviral agents: The effect of charge number and distance
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A series of "viologen"derivatives (4,4′-bipyridinium salts) carrying between 1 and 90 charges per molecule have been prepared and investigated for their activity against human immunodeficiency virus (HIV), herpes simplex virus (HSV), vesicular stomatitis, Punta Toro virus, Sindbis virus, Reovirus, and respiratory syncytial viruses. In general, most of the compounds showed good activities against HIV-1 (strain IIIB). In particular, compound 36 exhibited the highest in vitro activity and selectivity index against HIV-1 (strain IIIB) (EC50 = 0.26 ± 0.08 μM, SI = 75.7) in MT-4 cells. The results imply that the antiviral activity requires an optimal number and distance of the positive charges.
- Asaftei, Simona,De Clercq, Erik
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supporting information; experimental part
p. 3480 - 3488
(2010/09/04)
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- COMPOUND COMPRISING PHENYL PYRIDINE UNITS
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Compounds of following formula (I) may be used in optoelectronic devices; wherein R1 is, independently at each occurrence, a C1-C20 aliphatic radical, a C3-C20 aromatic radical, or a C3-Cs
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Page/Page column 23-24
(2010/04/03)
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- Synthesis and orthogonal functionalization of [60]fullerene e,e,e-trisadducts with two spherically defined addend zones
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e,e,e-Trisadducts 13 and 15 have been prepared by a highly regioselective threefold cyclopropanation of tripodal malonates 10 and 12 with C60. The yield and regioselectivity depend on the length and structure of the tethers that connect the malonate units to the focal benzene core of 13-15. As a consequence of the template-directed synthesis, all ce.e-trisadducts were formed as in/out isomers exclusively and contain two spherically well-defined addend zones with equatorial and polar orientation, respectively. By variation of the outer malonate termini of the tethers, selective functionalization of the equatorial addend zone could be achieved, thus leading to fine-tuning of intermolecular interactions, such as solubility or aggregation phenomena. After removal of the focal benzene moiety in 14 and 15, selective functionalization of the polar addend zone could be achieved. Strong intramolecular hydrogen-bonding networks of the polar substituents in the polar addend zone could be observed by 1H NMR spectroscopic analysis. By orthogonal functionalization of both addend zones, fullerene derivatives 44-48 could be synthesized as one single in/out isomer, thus greatly enhancing the potential of e,e,e-trisadducts as building blocks in supramolecular architectures.
- Beuerle, Florian,Hirsch, Andreas
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scheme or table
p. 7434 - 7446
(2010/03/24)
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- Luminescent amphiphilic dendrimers with oligo(p-phenylene vinylene) core branches and oligo(ethylene oxide) terminal chains: Syntheses and stimuli-responsive properties
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A class of new dendrimers consisting of hydrophobic oligo(p-phenylene vinylene) core branches and hydrophilic oligo(ethylene oxide) terminal chains was synthesized. These amphiphilic dendritic molecules are highly luminescent and exhibit critical micellization behaviors. They also show a lower critical solution temperature (LCST) in an aqueous medium. Both the critical micelle concentration (CMC) and LCST increased with increasing branch number and the ratio of the hydrophilic oligo(ethylene oxide) to hydrophobic oligo(p-phenylene vinylene) moieties. Besides, a temperature-dependent phase transition from a clear to cloudy aqueous solution was observed. The temperature-induced phase transition was also reflected by fluorescence quenching, 1H NMR resonance peak broadening, and UV-vis absorption shift arising from the hydrophobic conjugated core. These changes in the phase structure and photophysical properties were demonstrated to be highly reversible, indicating some interesting stimuli-responsive behaviors. The Royal Society of Chemistry.
- Chang, Dong Wook,Dai, Liming
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p. 364 - 371
(2008/02/03)
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- Reversible photon-mode phosphorescence switching of heteroleptic cyclometalated iridium(III) complexes via photochromic bisthienylethene switch linked to ancillary ligand
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A novel class of heteroleptic IrIII complexes covalently linked with photochromic bisthienylethene (BTE) switch showed optically addressed modulation in blue, green, and yellow phosphorescence. Additional enhancement of phosphorescence modulati
- Lee, Insuk,You, Ngmin,Lim, Seon-Jeong,Park, Soo Young
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p. 888 - 889
(2008/02/12)
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- TARGETING CHELANTS AND CHELATES
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Novel chelants and other compounds, and compositions thereof are provided, that are useful for detection and treatment of cancer and other abnormal and disease-state cells and tissues.
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Page/Page column 62
(2010/10/20)
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- Process for side-chain bromination of alkylbenzenes
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A process for the side-chain bromination of alkylbenzenes according to Formula (I) wherein R1 is C1-C6-alkyl; R2 is H or C1-C6-alkyl which can be unsubstituted or substituted by one or more cyano groups; R3 is H or C1-C6-alkyl which can be unsubstituted or substituted by one or more cyano groups; comprising the steps of (1) dissolving the compound of Formula (I) in a solvent which is a non-aromatic non-halogenated hydrocarbon which can be substituted by one or more cyano groups; (2) adding a bromination agent selected from the group consisting of Br2 and N-bromoimides to the solution; and optionally (3) agitating the mixture at a temperature within the range of from room temperature to reflux temperature.
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Page/Page column 3; 4
(2010/11/23)
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- Improved process for side-chain bromination of alkyl-benzenes
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A process for the side-chain bromination of alkylbenzenes according to Formula (I) wherein R1 is C1-C6-alkyl; R2 is H or C1-C6-alkyl which can be unsubstituted or substituted by one or more cyano groups; R3 is H or C1-C6-alkyl which can be unsubstituted or substituted by one or more cyano groups; comprising the steps of (1) dissolving the compound of Formula (I) in a solvent which is a nonaromatic non-halogenated hydrocarbon which can be substituted by one or more cyano groups; (2) adding a bromination agent selected from the group consisting of Br2 and N-bromoimides to the solution; and optionally (3) agitating the mixture at a temperature within the range of from room temperature to reflux temperature.
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- A new trimeric cinchona alkaloid as a chiral phase-transfer catalyst for the synthesis of asymmetric α-amino acids
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A new trimeric cinchona alkaloid, the quaternary ammonium salt, α,α′,α″-tris[O(9)-allylcinchonidinium-(4- methylphenoxymethyl)]benzene trichloride, has been synthesized and used as an efficient phase-transfer catalyst in asymmetric alkylation of N-(diphen
- Siva, Ayyanar,Murugan, Eagambaram
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p. 2927 - 2933
(2007/10/03)
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- A highly efficient, preorganized macrobicyclic receptor for halides based on CH... and NH...anion interactions
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The preorganized, macrobicyclic azaphane (1) exhibits remarkable strong, selective fluoride binding comparable to the most effective bis(tren) cryptands despite binding anions via only three NH groups coupled with three CH hydrogen bond donors. The lower intrinsic affinity of CH donors is compensated by the high degree of preorganization exhibited by azacyclophane 1. Compound 1 is prepared via a tripod-tripod cyclization reaction between 1,3,5-tris- bromomethyl-benzene and an aliphatic tripodal hexatosylated polyamine, followed by the reduction of the resulting bicyclic tosylamine. The crystal structures of the bicyclic tosylamine 2 and four macrobicyclic polyammonium halide salts of 1 are reported. X-ray studies revealed the formation of inclusive 1:1 complexes of 1 with fluoride, chloride, bromide, and iodide. Potentiometric titrations showed very high binding constants for fluoride and chloride with a F -/Cl- selectivity of more than five logarithmic units. The final geometry of the anion cryptates is largely determined by optimization of NH and CH...anion interactions coupled with unfavorable anion-π repulsion for the larger anions.
- Ilioudis, Christos A.,Tocher, Derek A.,Steed, Jonathan W.
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p. 12395 - 12402
(2007/10/03)
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- DNA hydrolysis catalyzed by tris(diisopropyl-1,4,7-triazacyclononanes) ethane metal complexes
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Novel trinuclear coordinated ligands were designed using three of 1,4,7-triazacyclononane moieties with a tribromo linker. These ligands show greater capability and potency in association with various metal ions. Tris(diisopropyl-1,4,7-triazacyclononanes)ethane (2) associated with Cu 2+ and Ce4+ ions shows better reactivity to achieve DNA hydrolysis at 37 °C at pH 8 for 5 hr. Using high resolution of polyacrylamide gel electrophoresis, DNA cleavage reaction in Tris-HCl buffer causes a nicking site at the single-stranded region. Alternatively, the reaction in HEPES buffer shows a random DNA cleavage included the double-stranded region. Hydrolysis of phosphodiester bond mediated by trinuclear metal complex is capable of performing at the physiological temperature 37 °C, but it has a lower reactivity compared to mono- and di-nuclear metal complexes. The result suggests that trinuclear metal complexes have a bulky environment to prevent from going toward the phosphodiester bond. The design of an efficient chemical hydrolyase will be a challenge in order to construct a coordinate ligand with the enhancement of hydrolytic activity and the reduction of the steric environment.
- Cheng, Chien-Chung,Huang, Yan-Chen,Liu, Ming-Chan
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p. 1201 - 1208
(2007/10/03)
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- Synthesis of enantiopure axially chiral C3-symmetric tripodal ligands and their application as catalysts in the asymmetric addition of dialkylzinc to aldehydes
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The enantioselective synthesis of a novel-type C3-symmetric tripodal ligand that is composed of a central mesitylene-derived core and three functionalized, axially chiral biaryl subunits is described. The triol (M,M,M) -3 is a suitable catalyst for the enantioselective addition of dialkylzinc to various aromatic aldehydes with asymmetric inductions of up to 98% ee.
- Bringmann, Gerhard,Pfeifer, Robert-Michael,Rummey, Christian,Hartner, Kristina,Breuning, Matthias
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p. 6859 - 6863
(2007/10/03)
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- Polyaromatic amines. Part 3: Synthesis of poly(diarylamino)styrenes and related compounds
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The title compounds were synthesised and characterised as part of a study into new aromatic amines for charge transporting materials. Compounds 12-16, 20-24 and 27-34 are alkene linked triarylamines, compounds 35-36 are hydrazone derivatives and compounds 38-41 are pyrrole substituted triarylamines. Each compound was characterised by cyclic voltammetry.
- Plater, M. John,Jackson, Toby
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p. 4673 - 4685
(2007/10/03)
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- PROSTAGLANDIN CONJUGATES FOR TREATING OR PREVENTING BONE DISEASES
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This invention relates to prostaglandin-bisphosphonate conjugates. These conjugates are effective for treating or preventing bone diseases such as osteoporosis. These conjugates simultaneously deliver a prostaglandin agent for increasing bone formation and a bisphosphonate agent for inhibiting bone resorption.
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