Generation and reactions of organic radical cations in zeolites.

Review on synthesis and properties of high-energy-density liquid fuels: Hydrocarbons, nanofluids and energetic ionic liquids

Molecular photoswitches that are capable of storing solar energy, so-called molecular solar thermal storage systems, are interesting candidates for future renewable energy applications. In this context, substituted norbornadiene-quadricyclane systems have received renewed interest due to recent advances in their synthesis. The optical, thermodynamic, and kinetic properties of these systems can vary dramatically depending on the chosen substituents. The molecular design of optimal compounds therefore requires a detailed understanding of the effect of individual substituents as well as their interplay. Here, we model absorption spectra, potential energy storage, and thermal barriers for back-conversion of several substituted systems using both single-reference (density functional theory using PBE, B3LYP, CAM-B3LYP, M06, M06-2x, and M06-L functionals as well as MP2 calculations) and multireference methods (complete active space techniques). Already the diaryl substituted compound displays a strong red-shift ...

http://pubs.acs.org/doi/pdf/10.1021/acs.jpcc.5b11489

Comparative Ab-Initio Study of Substituted Norbornadiene-Quadricyclane Compounds for Solar Thermal Storage.

The photoisomerization of norbornadiene using M–Ti–MCM-41 (M = V, Fe and Cr) has been studied to develop an alternative for solar energy accumulation and high energy aerospace fuel synthesis. The photocatalysts were prepared via hydrothermal method and characterized by EDX, XRD, N 2 adsorption–desorption, TEM, UV–vis, XPS and IR. With the same Si/M ratio in starting materials, the final concentration of V in the photocatalyst is significantly lower than that of Fe and Cr. V 5+ and Fe 3+ ions are highly dispersed in Si–O framework with tetrahedral coordination when the metal content is low, and the ordered structure is well retained. However, some species in higher coordination and polymerized environments present with increasing metal content, and the ordered structure becomes to collapse. Cr ions are difficult to get into the framework with various species like extraframework Cr 6+ and bulk Cr 2 O 3 formed, also the ordered structure is greatly destroyed. Under UV irradiation, the transition metal ions can improve the photoisomerization activity, with the order of V > Fe > Cr. The activities of V– and Fe–Ti–MCM-41 rise with the increase of Si/M ratio, whereas the performance of Cr–Ti–MCM-41 is irregular. The photocatalysts do not exhibit any activity under visible light, regardless of their absorption in visible-light region. The activity is closely related to the extent of dispersion and local structure of metal ions, about which an indirect excitation process of Ti–O species is suggested.

Photocatalytic isomerization of norbornadiene to quadricyclane over metal (V, Fe and Cr)-incorporated Ti–MCM-41

In den letzten 15 Jahren hat sich die Aktivierung durch Einelektronentransfer als ein bedeutendes Konzept zur Entwicklung neuer Reaktionen bewahrt und vielfach Anwendung bei selektiven Umsetzungen zunehmend komplexerer Verbindungen gefunden Der vorliegende Ubersichtsartikel soll die grose Reaktionsvielfalt der Radikalkationen, unabhangig davon, ob sie nach chemischer, elektrochemischer oder photoinduzierter Einelektronenoxidation entstehen, in ubersichtlicher Form prasentieren Um den Leser mit Elektronentransferkonzepten vertraut zu machen, wird eine neuartige, ubersichtliche Einteilung der Radikalkationen-Reaktionen vorgenommen, so das verschiedenartigste Reaktivitatsmuster auf schnell einsichtige Art und Weise nachvollzogen werden konnen Nach Moglichkeit werden thermodynamische und kinetische Daten aufgefuhrt

and Iliana L. Schilke

Papers

The Energetics of Valence Isomerization in the Norbornadiene-Quadricyclane System.