First Synthesis of the Inherently Chiral Trans-4′ Bisadduct of C59N Azafullerene by Using Cyclo-[2]-dodecylmalonate as a Tether

The multiaddition chemistry of azafullerene C₅₉N has been scarcely explored, and the isolation of pure bisadducts is in its infancy. Encouraged by the recent regioselective synthesis of the inherently chiral equatorial_face bisadduct of C₅₉N, we focused on the isolation of the first trans-4 bisadduct in a simple two-step approach. The first regioselective synthesis of the trans-4 bisadduct of C₅₉N by using cyclo-[2]-dodecylmalonate as a tether is now reported. The newly synthesized bisadduct has C₁ symmetry, as evidenced by ¹³C NMR, while X-ray crystallography validated the trans-4′ addition pattern. Furthermore, the inherently chiral trans-4′ C₅₉N bisadduct was enantiomerically resolved, and the mirror-image relation of the two enantiomers was probed by circular dichroism spectroscopy. Finally, UV-Vis and redox assays suggested that the addition pattern has a reflection in the light-harvesting and redox properties of the bisadduct.     

Comparative study of different types of graphenes as electrocatalysts for ascorbic acid

A comparative study regarding the electrocatalytic activity of graphene oxide (GO), chemically-reduced graphene oxide (crGO) and graphene produced by direct liquid exfoliation (dG) is presented. Sensors were developed by modifying glassy carbon (GC) electrodes with GO, crGO and dG and ascorbic acid was used as a pilot analyte. GC/GO electrodes offer substantially lower oxidation overpotential, up to 350 mV, compared with GC/crGO, GC/dG and unmodified GC electrodes. In addition, the different carbon-to-oxygen atomic ratios in GO, as it occurs depending on the synthetic route, were found to have a remarkable effect on the performance of the sensors. Reduction of GO was achieved by immersing the modified electrodes into a stirred solution of NaBH₄ for 10 min at room temperature. This process was used alternatively of the time consuming and laborious process of hydrazine, and its effectiveness was confirmed by cyclic voltammetry and electrochemical impedance spectroscopy. Analytical utility of the sensors is demonstrated.     

The missing mass squared dependence of the average charged particle multiplicity in the reaction K+p → KoX++ from 5–16 GeV/c

The average charged particle multiplicity, 〈n_ch(M_X²)〉, in the reaction K⁺p→K^oX⁺⁺ is studied as a function of the mass squared, M_X², of the recoil system X and also as a function of the K^o transverse momentum, p_T, at incident momenta of 5.0, 8.2 and 16.0 GeV/c. The complete data samples yield distributions which are not independent of c.m. energy squared, s, They exhibit a linear dependence on log (M_X²_X/M_o²)[M_o²=1 GeV²] with a change in slope occurring for M_X²≈s/2, and do not agree with the corresponding distributions of 〈n_ch〉 as a function of s for K⁺ p inelastic scattering. Sub-samples of the data for which K^o production via beam fragmentation, central production and target fragmentation are expected to be the dominant mechanisms show that, within error, the distribution of 〈n_ch(M_X²)〉 versus M_X² is independent of incident momentum for each sub-sample separately. In particular in the beam fragmentation region the 〈n_ch(M_X²)〉 versus M_X² distribution agrees rather well with that of 〈n_ch〉 versus s for inelastic K⁺p interactions. The latter result agrees with recent results on the reactions pp → pX and π^?p → pX in the NAL energy range. Evidence is presented for the presence of different production mechanisms in these separate regions.     

Slow proton andΔ ++ production inK + p interactions at 70 GeV/c

The inclusive inelastic processesK ⁺ p→pX ⁺ andK ⁺ p→Δ ⁺⁺ X ⁰ are studied at an incident momentum of 70 GeV/c. The data comes from the Big European Bubble Chamber BEBC filled with hydrogen, exposed to an rf reparatedK ⁺ beam at the CERN SPS accelerator. The inclusive cross section for protons with laboratory momentump _LAB≦1.2 GeV/c is equal to (6.1±0.1) mb. InclusiveΔ ⁺⁺-production is studied for |t _{p, Δ}|<1.0(GeV/c)². Comparisons are made with otherK ⁺ p data and withpp data at 69 GeV/c. Evidence is found for Pomeron exchange at the beam vertex both for slow proton andΔ ⁺⁺-production as well as for absorptive pion exchange at the (p,Δ ⁺⁺) vertex.     

Leading particles and charged particle multiplicity in annihilation and non-annihilation interactions

Using data from our K^?p experiment at 8.25 GeV/c we have investigated the charged particle multiplicity, and the variation of charged pion multiplicity as a function of the effective mass squared of all pions, for various samples of data, and compared our results with $\text{p}$p annihilation data and pp data. Evidence is presented which suggests that the difference in behaviour between the annihilation and non-annihilation data is not due to some specific mechanism such as baryon exchange, but is related to the absence of leading particles in the former case.     

Phenomenological comparison of inelastic electron-proton scattering with reaction K+ p → K0 + anything at 5, 8.2 and 16 GeV/c

We present an analysis of the reaction K⁺p → K⁰ + anything at incident momenta of 5, 8.2 and 16 GeV/c in terms of the Björken variables gw and x. Assuming dominance of ? exchange, we derive the structure function F₂(x, y) which is found similar to the one obtained in deep inelastic electroproduction.