Borate complexes of benzohydroxamic acid and some of its derivatives

Ultraviolet spectrophotometric measurements in dilute aqueous solution give pK(a) values of 8.78, 8.27, 8.96 and 8.68, respectively, for benzohydroxamic, N-phenylbenzohydroxamic, p-methoxybenzohydroxamic and N-methyl-p-methoxybenzohydroxamic acids. The acids carrying no substituent on nitrogen form 1:1 complexes with boric acid according to the general equation RCONHOH + H(3)BO(3) --> (1:1 complex)(-) + H(+). Equilibrium constants (log K) were found to be -5.70 for benzohydroxamic acid and -5.8 for p-methoxybenzohydroxamic acid. The complexes behave as very weak monoprotic acids and decompose at high pH to yield borate ions and the corresponding hydroxamate ions. The N-substituted hydroxamic acids showed no reaction with boric acid under the same conditions.     

Correlations of high transverse momentum π0 pairs produced at the CERN ISR

Correlations of two π⁰ mesons with transverse momenta up to 10 GeV/c have been measured utilizing apparatus with large azimuthal acceptance. The data are analysed in the context of constituent scattering models, and also compared with a simple “back-ground” hypothesis.     

Results from a search for light-mass dark matter with a p-type point contact germanium detector

We report on several features in the energy spectrum from an ultralow-noise germanium detector operated deep underground. By implementing a new technique able to reject surface events, a number of cosmogenic peaks can be observed for the first time. We discuss an irreducible excess of bulklike events below 3 keV in ionization energy. These could be caused by unknown backgrounds, but also dark matter interactions consistent with DAMA/LIBRA. It is not yet possible to determine their origin. Improved constraints are placed on a cosmological origin for the DAMA/LIBRA effect.     

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Azonia polycyclic quinones,o-diazo-oxides and related products

4α-Azoniaanthracene-5,6- and 5,8-dione salts have been prepared by nitric acid oxidation of their respective diols, and are shown to function as either an electrophilic dienophile or a diene component in Diels-Alder-type reactions. Several azonia o-quinones have been treated with tosylhydrazine in methanol saturated with hydrogen chloride to give unusually stable o-diazo-oxides. A four-step dehydroxylation procedure is detailed for the conversion of .5,6-dihydroxy-4α-azonia-anthracene salts to new 5-hydroxy-4α-azoniaanthracene salts.     

Absolute branching fraction measurements of exclusive D+ semileptonic decays

Using data collected at the psi(3770) resonance with the CLEO-c detector at the Cornell e+e- storage ring, we present improved measurements of the absolute branching fractions of D+decays to K0e+ve, pi0e+ve, K*0e+ve, and p0e+ve, and the first observation and absolute branching fraction measurement of D+ --> omega e+ve. We also report the most precise tests to date of isospin invariance in semileptonic D0 and D+ decays.     

Decay pathways and entry-state population in (α, xnγ) and (3He, xnγ) reactions on 150Nd

Exclusive neutron spectra and angular distributions have been measured by n-γ coincidence techniques for $\text{(α, x}\text{n}\text{γ)}\text{and}\text{(}{}^3\text{He}\text{, x}\text{n}\text{γ)}$ reactions on ¹⁵⁰Nd in the 25–44 MeV range. The results show that pre-equilibrium processes dominate low-energy light-ion induced reactions at certain beam energies. Analysis of the yrast γ-ray cascades in the residual nuclei shows that a well-defined minimum entry-state spin exists in final nuclei populated by pre-equilibrium processes. This in turn implies the existence of a minimum classical impact parameter for these reactions. These results are discussed in terms of phenomenological models of the reaction mechanisms.     

One-pot tandem decarboxylative allylation-Heck cyclization of allyl diphenylglycinate imines: rapid access to polyfunctionalized 1-aminoindanes

1-Aminoindanes are generated from allyl diphenylglycinate imines employing a "one-pot" palladium-catalyzed decarboxylative allylation-Heck cyclization cascade. Variation of both the aryl and allyl moieties leads to a diverse range of polycyclic imines, amenable to the synthesis of natural products and other biologically relevant small molecules.