Search results for "TRIP"

Ti(iv)-amino triphenolate complexes as effective catalysts for sulfoxidation

2010

C 3 -symmetric Ti (IV) amino triphenolate complexes efficiently catalyze, without previous activation and in excellent yields, the oxidation of sulfides at room temperature, using both CHP and the more environment friendly aqueous hydrogen peroxide as terminal oxidants, with catalyst loadings down to 0.01%. The Ti(IV) catalysts and the intermediate Ti(IV)-peroxo complexes have been characterized in solution by 1H NMR and ESI-MS techniques and via density functional studies.

Missione archeologica in Libia dell’Università degli Studi di Palermo; Nicola Bonacasa

2021

The paper contains a brief survey of the activities and objectives of the Archaeological Mission of Palermo University in Libya and a profile of Nicola Bonacasa, who led the Mission for forty years (1976-2015).

Role of vitreous matrix on the optical activity of Ge-doped silica

2003

Abstract We report an experimental study on the relationship between the optical activity of Ge-oxygen deficient centers and dynamic properties and conformational heterogeneity of vitreous matrix in silica. We focus our attention on the absorption band at ∼5.2 eV (B 2β ) and on the two related emissions at ∼4.2 eV (α E ) and at ∼3.1 eV (β). From the temperature dependence of B 2β band we estimate a mean energy value of 26 meV for local vibrational modes coupled to the electronic transition, suggesting that the chromophore and its surrounding have access to low frequency dynamics. From the thermal behavior of the two emissions we distinguish the two competitive relaxation processes from the …

A theory ofnonverticaltriplet energy transfer in terms of accurate potential energy surfaces: The transfer reaction from π,π* triplet donors to 1,3,5…

2004

Triplet energy transfer (TET) from aromatic donors to 1,3,5,7-cyclooctatetraene (COT) is an extreme case of "nonvertical" behavior, where the transfer rate for low-energy donors is considerably faster than that predicted for a thermally activated (Arrhenius) process. To explain the anomalous TET of COT and other molecules, a new theoretical model based on transition state theory for nonadiabatic processes is proposed here, which makes use of the adiabatic potential energy surfaces (PES) of reactants and products, as computed from high-level quantum mechanical methods, and a nonadiabatic transfer rate constant. It is shown that the rate of transfer depends on a geometrical distortion paramet…

Omat projektit : henkilöhahmojen kapinat Tomas Arvidssonin romaaneissa Utanförskapet ja Trippelstöten

2006

Reto un apdraudēto augu sugu jūrmalas zilpodzes (Eryngium maritimum L.) un jūrmalas sālsasteres (Aster tripolium L.) audu fenolu saturs un antioksida…

2018

Jūrmalas zilpodze (Eryngium maritimum L.) un jūrmalas sālsastere (Aster tripolium L.) ir retas un apdraudētas sugas, kuras ir ierakstītas Latvijas Sarkanās grāmatas 1. kategorijā. Abas sugas ir ievērojamas ar vērtīgām dabas vielām ar potenciālu pielietojumu farmokoloģijā, kosmētikā un pārtikas nozarē. •Darba mērķis - noskaidrot dažādu saharozes un nitrātu koncentrāciju barotnē ietekmi uz kopējo fenolu saturu un antioksidatīvo aktivitāti jūrmalas zilpodzes un jūrmalas sālsasteres dzinumu kultūrās. •Darba hipotēze - samazināta nitrātu koncentrācija un palielināta saharozes koncentrācija barotnē veicina fenolu sintēzi un ekstraktu antioksidatīvo aktivitāti audu kultūrā audzētajos dzinumos. Pēt…

H-2, H-3(+) and the age of molecular clouds and prestellar cores

2012

Measuring the age of molecular clouds and prestellar cores is a difficult task that has not yet been successfully accomplished although the information is of paramount importance to help in understanding and discriminating between different formation scenarios. Most chemical clocks suffer from unknown initial conditions and are therefore difficult to use. We propose a new approach based on a subset of deuterium chemistry that takes place in the gas phase and for which initial conditions are relatively well known. It relies primarily on the conversion of H 3 + into H 2D + to initiate deuterium enrichment of the molecular gas. This conversion is controlled by the ortho/para ratio of H2 that i…

2020

Abstract. Aerosol mass spectrometers (AMS) are frequently applied in atmospheric aerosol research in connection with climate, environmental or health-related projects. This is also true for the measurement of the organic fraction of particulate matter, still the least understood group of components contributing to atmospheric aerosols. While quantification of the organic and/or inorganic aerosol fractions is feasible, more detailed information about individual organic compounds or compound classes can usually not be provided by AMS measurements. In this study, we present a new method to detect organic peroxides in the particle phase in real-time using an AMS. Peroxides (ROOR') are of high i…

Discotic Twin and Triple Molecules with Charge-Transfer Interactions in Langmuir−Blodgett Films

1996

X-ray and atomic force microscopy observations reveal features of the surface morphology of Langmuir-Blodgett (LB) films from discotic donor-acceptor molecules with strong core-to-core interactions caused by a charge-transfer (CT) complexation. The compounds are designed to be twin and triple molecules composed of chemically connected donor (triphenylene) and acceptor (trinitrofluorenone) fragments which display liquid crystalline structure in the bulk state. The LB films from these compounds possess edge-on orientation of molecules within monolayers with a smooth surface on a submicron scale but with substantial macroscopic imperfections. These imperfections are represented by the micron s…

Origin and age of Australian Chenopodiaceae

2005

Abstract We studied the age, origins, and possible routes of colonization of the Australian Chenopodiaceae. Using a previously published rbc L phylogeny of the Amaranthaceae–Chenopodiaceae alliance (Kadereit et al. 2003) and new ITS phylogenies of the Camphorosmeae and Salicornieae, we conclude that Australia has been reached in at least nine independent colonization events: four in the Chenopodioideae, two in the Salicornieae, and one each in the Camphorosmeae, Suaedeae, and Salsoleae. Where feasible, we used molecular clock estimates to date the ages of the respective lineages. The two oldest lineages both belong to the Chenopodioideae ( Scleroblitum and Chenopodium sect. Orthosporum / Dy…