61842-44-2Relevant articles and documents
Multiple hydrogen-bond-induced supramolecular nanostructure from a pincer-like molecule and a [60]fullerene derivative
Zhuang, Junpeng,Zhou, Weidong,Li, Xiaofang,Li, Yongjun,Wang, Ning,He, Xiaorong,Liu, Huibiao,Li, Yuliang,Jiang, Li,Huang, Changshui,Cui, Shuang,Wang, Shu,Zhu, Daoben
, p. 8686 - 8693 (2005)
A new supramolecular self-assembled system between a perylene bisimide bearing diaminopyridine-substituted isophthalamide groups (PP) and a [60]fullerene containing barbituric acid moiety (C60bar) through a complementary six-point hydrogen-bonding interaction was constructed. The formation of hydrogen bonding was confirmed by 1H NMR spectra studies in CDCl3. Fluorescence quenching experiments indicated that the fluorescence of PP was greatly quenched by the hydrogen-bonded C60bar (Ksv=2.71×104 M-1). A steady and rapid cathodic 0.15 μA cm-2 photocurrent response of the PP/C 60bar film deposited onto an ITO electrode was produced under the irradiation of 20 mW cm-2 white light, indicating the presence of photo-induced electron transfer between PP and C60bar. TEM images showed that spherical particles were fabricated by the self-assembly of PP and C60bar through hydrogen-bonding interaction.
Coordination networks based on nitrile-functionalized borate anions
Harloff, Joerg,Karsch, Markus,Lund, Henrik,Schulz, Axel,Villinger, Alexander
supporting information, p. 1330 - 1341 (2014/07/07)
Salts of cyano borates bear potential of forming coordination polymers with solvent-filled voids as a source for porous materials. Herein we describe the synthesis and properties of novel cyano borates Na[H-B(O-C12H 8-CN)3], Na[B(O-C12H8-CN) 4] (C12H8 = biphenyl) and Na[B{O-C 6H3-(CN)2}4], as well as a new modification of Na[B(O-C6H4-CN)4]. Crystal structures of the sodium borates and the starting materials HO-C 6H3-(CN)2 and HO-C12H8-CN (new modification) are discussed as well. Data of nitrogen sorption experiments revealed a notable surface area in solvent-free Na[H-B(O-C12H 8-CN)3]. Copyright
Cooperativity and tunable excited state deactivation: Modular self-assembly of depsipeptide dendrons on a Hamilton receptor modified porphyrin platform
Gnichwitz, Jan-Frederik,Wielopolski, Mateusz,Hartnagel, Kristine,Hartnagel, Uwe,Guldi, Dirk M.,Hirsch, Andreas
supporting information; experimental part, p. 8491 - 8501 (2009/02/02)
A series of novel supramolecular architectures were built around a tin tetraphenyl porphyrin platform 6 - functionalized by a 2-fold 1-ethyl-3-3-(3-dimethylaminopropyl)carbodiimide (EDC) promoted condensation reaction - and chiral depsipeptide dendrons of different generations 1-4. Here, implementation of a Hamilton receptor provided the necessary means to keep the constituents together via strong hydrogen bonding. Characterization of all architectures has been performed, including 4 which is the fourth generation, on the basis of NMR and photophysical methods. In particular, several titration experiments were conducted suggesting positive cooperativity, an assessment that is based on association constants that tend to be higher for the second binding step than for the first step. Importantly, molecular modeling calculations reveal a significant deaggregation of the intermolecular network of 6 during the course of the first binding step. As a consequence, an improved accessibility of the second Hamilton receptor unit in 6 emerges and, in turn, facilitates the higher association constants. The features of the equilibrium, that is, the dynamic exchange of depsipeptide dendrons 1-4 with fullerene 5, was tested in photophysical reference experiments. These steady-state and time-resolved measurements showed the tunable excited-state deactivations of these complexes upon photoexcitation.
Total synthesis of rhein and diacerhein via a directed ortho metalation of an aromatic substrate
Gonnot, Vanessa,Tisserand, Steve,Nicolas, Marc,Baati, Rachid,Mioskowski, Charles
, p. 7117 - 7119 (2008/03/11)
An efficient total synthesis of rhein and diacerhein has been accomplished by relying on a remarkable regioselective directed ortho metalation (DOM) followed by a one-pot two step addition-cyclization reaction, generating phthalide 5 intermediate efficiently.
Poly(ethylene glycol)-supported nitroxyls: Branched catalysts for the selective oxidation of alcohols
Ferreira, Pedro,Phillips, Emyr,Rippon, David,Shik, Chi Tsang,Hayes, Wayne
, p. 6851 - 6859 (2007/10/03)
Nitroxyl radicals such as 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) are highly selective oxidation catalysts for the conversion of primary alcohols into the corresponding aldehydes. In this study, direct tethering of TEMPO units onto linear poly(ethylene glycol) (PEG) has afforded macromolecular catalysts that exhibit solubility in both aqueous and organic solvents. Recovery of the dissolved polymer-supported catalyst has been carried out by precipitation with a suitable solvent such as diethyl ether. The high catalyst activities and selectivities associated traditionally with nitroxyl-mediated oxidations of alcohols are retained by the series of "linker-less" linear PEG-TEMPO catalysts in which the TEMPO moiety is coupled directly to the PEG support. Although the selectivity remains unaltered, upon recycling of the linker-less polymer-supported catalysts, extended reaction times are required to maintain high yields of the desired carbonyl compounds. Alternatively, attachment of two nitroxyl radicals onto each functionalized PEG chain terminus via a 5-hydroxyisophthalic acid linker affords branched polymer-supported catalysts. In stark contrast to the linker-less catalysts, these branched nitroxyls exhibit catalytic activities up to five times greater than 4-methoxy-TEMPO alone under similar conditions. In addition, minimal decrease in catalytic activity is observed upon recycling of these branched macromolecular catalysts via solvent-induced precipitation. The high catalytic activities and preservation of activity upon recycling of these branched systems is attributed to enhanced regeneration of the nitroxyl species as a result of intramolecular syn-proportionation.
THIAZINE AND OXAZINE DERIVATIVES AS MMP-13 INHIBITORS FOR TREATING ARTHRITIS
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Page 22, (2010/02/05)
A compound selected from those of formula (I): wherein: ? X1, X2, and X3 represent nitrogen or -CR3 in which R3 represents hydrogen, alkyl, amino, alkylamino, dialkylamino, hydroxy, alkoxy, or halogen, ? Gl represents oxygen or S(O)p in which p is from 0 to 2, ? G2 represents carbon-carbon triple bond, C=O, C=S, S(O)q in which q is from 0 to 2, or a group of formula (i/a): in which YI and Y2 are as defined in the description, ? n is fromO to 6, Zl represents -CR4R5, wherein R4 and R5 are as defined in the description, ? A represents 5- or 6-membered monocycle or bicycle aryl, heteroaryl, cycloalkyl, or heterocycloalkyl, ? RI represents hydrogen, alkyl, alkenyl, alkynyl, (these groups may be optionally substituted as defined in the description) or the group of formula (i/b): in which s, Z2, B, t and G3 are as defined in the description, and optionally, its optical isomers , N-oxide, and addition salts thereof with a pharmaceutically-acceptable acid or base, and medicinal products containing the same are useful as specific inhibitors of type-13 matrix metalloprotease, for the treatment of i.a arthritis and cancer.
Molecular recognition of carbohydrates by artificial receptors: Systematic studies towards recognition motifs for carbohydrates
Mazik, Monika,Sicking, Willi
, p. 664 - 670 (2007/10/03)
The synthesis and binding properties for carbohydrates of several artificial, acyclic receptors containing two or three heterocyclic recognition units covalently attached to a phenyl spacer is described. These host molecules having uncharged hydrogen-bonding sites were used in a systematic study towards the evaluation of recognition motifs for carbohydrates. A novel effective, acyclic hydrogen-bonding receptor possessing naphthyridine-amide moieties as heterocyclic recognition units has been developed.
Mechanism of Site-Directed Protein Cross-Linking. Protein-Directed Selectivity in Reactions of Hemoglobin with Aryl Trimesates
Kluger, Ronald,de Stefano, Vittorio
, p. 214 - 219 (2007/10/03)
Site-directed cross-linking of hemoglobin has become an efficient way to produce a structurally defined altered protein with desirable functional properties. The reagent trimesoyl tris(3,5-dibromosalicylate) (1) introduces a bis amide cross-link derived from the ∈-amino groups of the side chains of the two β-Lys-82 residues in human hemoglobin. The basis of its specificity was investigated using a set of analogues of 1 (2-12). There are marked differences in the reaction patterns of these compounds with amino groups in hemoglobin compared to reactions with n-propylamine. The compounds that effectively modify the protein contain a carboxyl group ortho to the phenolic oxygen of the ester, while materials with meta or para carboxyl groups give little or no reaction. In contrast, the reactions with n-propylamine are slowest with the ortho carboxyl materials. Addition of the unreactive compound 5 to a solution containing hemoglobin reduces the ability of 1 to modify the protein, showing that the unreactive compound binds but does not react. On the basis of these observations and the known reaction patterns of salicylates, it is clear that the environment in the protein controls the reaction, regardless of the inherent reactivity of the reagent. We propose that the carboxyl group positions the reagent critically within the protein. Only the ortho arrangement permits transfer of the acyl function to the nucleophile.
