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Teas and spices are widely known to have high antioxidant content and reactivity. The antioxidant properties are derived from the contained phenolic compounds. The health benefits gained from consuming various teas and spices differ based on the structure of the antioxidants present. When the two are mixed, the net antioxidant effect can change. In this study, the antioxidant properties of black tea combined with cloves, cinnamon, ginger, black pepper, chai blend, turmeric, and cardamon were studied using the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) radical assay followed by quantitative measurements with an ultraviolet-visible spectrometer. Significant interactions were observed only with cloves and cinnamon but, interestingly, the observed correlations were negative. The number of trolox equivalents in the pure spices studied varied substantially, led by cloves and then cinnamon; the remainder had considerably lower—but similar—levels of antioxidants. [ABSTRACT FROM AUTHOR]

Direct spectroscopy of a fast molecular ion beam offers many advantages over competing techniques, including the generality of the approach to any molecular ion, the complete elimination of spectral confusion due to neutral molecules, and the mass identification of individual spectral lines. The major challenge is the intrinsic weakness of absorption or dispersion signals resulting from the relatively low number density of ions in the beam. Direct spectroscopy of an ion beam was pioneered by Saykally and co-workers in the late 1980s, but has not been attempted since that time. Here, we present the design and construction of an ion beam spectrometer with several improvements over the Saykally design. The ion beam and its characterization have been improved by adopting recent advances in electrostatic optics, along with a time-of-flight mass spectrometer that can be used simultaneously with optical spectroscopy. As a proof of concept, a noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) setup with a noise equivalent absorption of ∼2 × 10-11 cm-1 Hz-1/2 has been used to observe several transitions of the Meinel 1-0 band of N2+ with linewidths of ∼120 MHz. An optical frequency comb has been used for absolute frequency calibration of transition frequencies to within ∼8 MHz. This work represents the first direct spectroscopy of an electronic transition in an ion beam, and also represents a major step toward the development of routine infrared spectroscopy of rotationally cooled molecular ions. [ABSTRACT FROM AUTHOR]

Ist Ladung wichtig? Direkte Vakuum ‐ UV ‐ Messungen von Ionisierungsenergien zeigen, dass die C ‐ H ‐ Insertion von Pt unter Bildung von H ‐ Pt ‐ CH3 hochexotherm ist, während die Bildung von PtCH2+H2 leicht endotherm ist. Experimente und Spin ‐ Bahn ‐ DFT ‐ Rechnungen zeigen überraschend ähnliche Energetiken für die Dehydrierung von Methan durch neutrales und kationisches Platin (rote Linien im Bild markieren experimentell bestimmte Energien). [ABSTRACT FROM AUTHOR]

The microsolvation of cobalt and nickel dications by acetonitrile and water is studied by measuring photofragment spectra at 355, 532 and 560–660 nm. Ions are produced by electrospray, thermalized in an ion trap and mass selected by time of flight. The photodissociation yield, products and their branching ratios depend on the metal, cluster size and composition. Proton transfer is only observed in water-containing clusters and is enhanced with increasing water content. Also, nickel-containing clusters are more likely to undergo charge reduction than those with cobalt. The homogeneous clusters with acetonitrile M2+(CH3CN)n(n= 3 and 4) dissociate by simple solvent loss; n= 2 clusters dissociate by electron transfer. Mixed acetonitrile/water clusters display more interesting dissociation dynamics. Again, larger clusters (n= 3 and 4) show simple solvent loss. Water loss is substantially favored over acetonitrile loss, which is understandable because acetonitrile is a stronger ligand due to its higher dipole moment and polarizability. Proton transfer, forming H+(CH3CN), is observed as a minor channel for M2+(CH3CN)2(H2O)2and M2+(CH3CN)2(H2O) but is not seen in M2+(CH3CN)3(H2O). Studies of deuterated clusters confirm that water acts as the proton donor. We previously observed proton loss as the major channel for photolysis of M2+(H2O)4. Measurements of the photodissociation yield reveal that four-coordinate Co2+clusters dissociate more readily than Ni2+clusters whereas for the three-coordinate clusters, dissociation is more efficient for Ni2+clusters. For the two-coordinate clusters, dissociation is viaelectron transfer and the yield is low for both metals. Calculations of reaction energetics, dissociation barriers, and the positions of excited electronic states complement the experimental work. Proton transfer in photolysis of Co2+(CH3CN)2(H2O) is calculated to occur viaa (CH3CN)Co2+–OH−–H+(NCCH3) salt-bridge transition state, reducing kinetic energy release in the dissociation. [ABSTRACT FROM AUTHOR]