Supramolecular synthesis of 3-indolyl-3-hydroxy oxindoles under neutral conditions in water

Various 3-indolyl-3-hydroxy oxindoles were prepared for the first time by supramolecular catalysis involving the reaction of beta-CD:isatin complexes with indoles under neutral conditions in water. beta-Cyclodextrin can be recovered and reused a number of times without loss of activity.     

New limit on the neutrinoless betabeta decay of 130Te

We report the present results of CUORICINO, a search for neutrinoless double-beta (0nu betabeta) decay of 130Te. The detector is an array of 62 TeO2 bolometers with a total active mass of 40.7 kg. The array is cooled by a dilution refrigerator shielded from environmental radioactivity and energetic neutrons, operated at approximately 8 mK in the Gran Sasso Underground Laboratory. No evidence for (0nu betabeta) decay was found and a new lower limit, T(1/2)(0nu) > or = 1.8 x 10(24) yr (90% C.L.) is set, corresponding to [m(nu)] < or = 0.2 to 1.1 eV, depending on the theoretical nuclear matrix elements used in the analysis.     

First nuclear moment measurement with radioactive beams by the recoil-in-vacuum technique: the g factor of the 2+1 state in 132Te

Following Coulomb excitation of the radioactive ion beam (RIB) 132Te at HRIBF we report the first use of the recoil-in-vacuum (RIV) method to determine the g factor of the 2(+)(1) state: g(973.9 keV 2(+) 132Te) = (+)0.35(5). The advantages offered by the RIV method in the context of RIBs and modern detector arrays are discussed.     

Supramolecular Copolymerization as a Strategy to Control the Stability of Self‐Assembled Nanofibers

A major challenge in supramolecular polymerization is controlling the stability of the polymers formed, that is, controlling the rate of monomer exchange in the equilibrium between monomer and polymer. The exchange dynamics of supramolecular polymers based on benzene‐1,3,5‐tricarboxamide (BTA) can be regulated by copolymerizing molecules with dendronized (dBTA) and linear (nBTA) ethylene glycol‐based water‐soluble side chains. Whereas nBTAs form long nanofibers in water, dBTAs do not polymerize, forming instead small spherical aggregates. The copolymerization of the two BTAs results in long nanofibers. The exchange dynamics of both the BTA monomers in the copolymer are significantly slowed down in the mixed systems, leading to a more stable copolymer, while the morphology and spectroscopic signature of the copolymers are identical to that of nBTA homopolymer. This copolymerization is the supramolecular counterpart of styrene/ maleic anhydride copolymerization.     

Photo-Fries rearrangement: Rearrangement of benzoyloxy compounds

Photo-Fries migration of the benzoyl group in 1-benzoyloxy-5-methoxy naphthalene, 1,4-dibenzoyloxy-2-methyl naphthalene, 1,4-dibenzoyloxy naphthalene, 1,5-dibenzoyloxy naphthalene, 8-benzoyloxy quinoline, 1,2-dibenzoyloxy benzene, 1,3-dibenzoyloxy benzene, and 1,4-dibenzoyloxy benzene afforded the corresponding mono and di-C-benzoyl products.

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Photo-Fries-Umlagerung: Umlagerung von Benzoyloxy-Verbindungen

Zusammenfassung Die Photo-Fries-Wanderung der Benzoylgruppe in 1-Benzoyloxy-5-methoxynaphthalin, 1,4-Dibenzoyloxy-2-methylnaphthalin, 1,4-Dibenzoyloxy-naphthalin, 1,5-Dibenzoyloxynaphthalin, 8-Benzoyloxychinolin, 1,2-Dibenzoyloxybenzol, 1,3-Dibenzoyloxybenzol und 1,4-Dibenzoyloxybenzol ergab die entsprechenden Mono- und Di-C-Benzoyl-Produkte.

     

Synthesis of the ‘southern’ tripeptide of Cyclomarins A and C having novel anti-tuberculocidal mode of action

The synthesis of the ‘southern’ tripeptide of Cyclomarins A and C has been described which includes two unusual amino acids. The unusual amino acids have been synthesized and coupled with l-alanine to obtain the tripeptide.     

AlCl3/PCC-SiO2-Promoted Oxidation of Azaindoles and Indoles

Abstract

A simple and efficient method is described for the oxidation of 7-azaindoles and indoles to 7-azaisatins and isatins using pyridinium chlorochromate–silica gel (PCC-SiO₂) with the aid of Lewis acid catalyst aluminium chloride (AlCl₃) in dichloroethane. Simplicity of the reaction conditions, easy workup procedure, and good yields are the key features of this protocol.     

Modeling of programming time of nanocrystal flash memory cells

Charging dynamics of nanocrystals in the emerging silicon nanocrystals-based flash memory is explained using a simplified engineering model based on effective mass approximation. The model includes the presence of discrete energy levels in the nanocrystals and also the effect of shift in energy levels in the nanocrystals with more than one electron. The simulated results of shift in threshold voltage as a function of programming time, and the effect of gate voltage and drain voltage on the programming speed agree very well with the experimental results. The tunnel mass of electron in the oxide, which is used as a fit parameter, takes into account the effect of strain and crystallographic orientational effects. Assumptions and limitations of the model are discussed.