Behavior of binary alcohol mixtures adsorbed on graphite using calorimetry and scanning tunneling microscopy

The mixing behavior of binary combinations of linear alcohols adsorbed from their liquids is studied by calorimetry and scanning tunneling microscopy (STM). In particular, we consider combinations of primary alcohols that differ by a single methylene group. Where the shorter alcohol has an odd number of carbon atoms, the combination is found to mix, essentially, ideally on the surface. However, for combinations where the shorter alcohol has an even number of carbon atoms, we find that there is molecular complex formation for shorter members but ideal mixing for longer (n>12) homologues. This extends previous work in this area by the determination of the limits of surface molecular complex formation. We also exploit STM to address this unexpected complex formation.     

Extending pummerer reaction chemistry. Application to the total synthesis of (+/-)-dibromoagelaspongin

The sponge metabolite dibromoagelaspongin was synthesized in 16 steps from imidazole. The route features two successive oxidative cyclizations with complete control of regiochemistry to deliver the unusual triaminomethane core of the target. These oxidative cyclizations likely resulted from Pummerer-like processes on the imidazole-2-sulfoxide (sulfide) precursors.     

A renormalizable field theory: The massive Gross-Neveu model in two dimensions

The Euclidean massive Gross-Neveu model in two dimensions is just renormalizable and asymptotically free. Thanks to the Pauli principle, bare perturbation theory with an ultra-violet cut-off (and the correct ansatz for the bare mass) is convergent in a disk, whose radius corresponds by asymptotic freedom to a small finite renormalized coupling constant. Therefore, the theory can be fully constructed in a perturbative way. It satisfies the O.S. axioms and is the Borel sum of the renormalized perturbation expansion of the model     

The liquid-phase reaction of CCl3 radicals with primary alcohols

The kinetics of gamma-radiation-induced free-radical reactions in carbon tetrachloride solutions of ethanol and n-pentanol were studied in the range of 0.05–0.80M and 25–170°C. The rate constant for the reaction was found as The activation energy is larger by 0.8 kcal/mol than for secondary alcohols, while the A₁ factors are about the same.     

The kinetics of radiation induced hydrogen abstraction by CCl3 radicals in the liquid phase: Cyclanes

The kinetics of gamma-radiation induced free radicals reactions in carbon tetrachloride solutions of cyclohexane, cyclooctane and cyclododecane were studied in the range of 27–190°C. The activation energies found were in the order c? C₆H₁₂ > c? C₁₂H₂₄ > c? C₈H₁₆, which was explained as due to their ring strain which has the same order. The following log k₁ was obtained using the known Arrhenius parameters for CCl₃ radical recombination:      

A miniature pulser-preamplifier for ultrasonic transducers

In order to avoid difficulties experienced with conventional ultrasonic systems using several feet of shielded cable to connect transducer and electronics, a miniature pulser-preamplifier was developed to fit the transducer holder. Its characteristics proved superior to most devices in common use.     

Photoconductivity in high purity,semiconducting CdF2

The photoconductivity spectra of high purity, semiconducting CdF₂, containing low concentrations of rare-earth donors, are interpreted in terms of a shallow trap 1260 ± 100 cm⁻¹ below the bottom of the conduction band and an excited bound state 1030 cm⁻¹ above the ground state.