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Kulkarni S.J.,Indian Institute of Chemical Technology | Rohitha C.N.,Indian Institute of Chemical Technology | Narender N.,Indian Institute of Chemical Technology | Koeckritz A.,Leibniz Institute of Catalysis
Journal of Porous Materials | Year: 2010

The in situ synthesis and encapsulation of metallo-octamethylcalix(4) pyrrole inside the pores of HMCM-41 catalyst is presented. The catalytic performance of the synthesized material was tested by the liquid phase oxidation of cyclohexene at room temperature using tert-butyl hydroperoxide as an oxidant. Similarly we have synthesized and encapsulated metallosalens in NaY zeolite and carried out the liquid phase oxidation of p-xylene at 100 °C using H2O2 as an oxidant. The central transition metal ions present in these two types of complexes were varied. The catalysts were characterized byXRD, IR spectra and thermal analysis. © 2009 Springer Science+Business Media, LLC. Source

Desens W.,Leibniz Institute of Catalysis | Werner T.,Leibniz Institute of Catalysis
Advanced Synthesis and Catalysis | Year: 2016

Concepts to facilitate the conversion of epoxides with carbon dioxide to the corresponding cyclic carbonates commonly focus on the activation of the epoxide. Herein we report a catalytic system which allows the simultaneous activation of carbon dioxide and the epoxide. This convergent activation concept is realized by combining a suitable carbene as catalyst for the carbon dioxide activation with a second catalytic system based on potassium iodide for epoxide activation. Initial experiments showed synergistic effects and thus proving the feasibility of this activation concept. Moreover a standard protocol was developed and the substrate scope under these conditions has been studied. Under mild and solvent-free conditions 14 epoxides could be converted. The respective cyclic carbonates were obtained in good to excellent yields with selectivities ≥ 99% after simple filtration. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Perez-Ruiz R.,University of Cologne | Fichtler R.,University of Cologne | Diaz Miara Y.,University of Cologne | Nicoul M.,University of Cologne | And 6 more authors.
Journal of Fluorescence | Year: 2010

The photophysical properties of a series of structurally related 4-aminophthalimides and the corresponding 5-aminophthalic hydrazides (luminols) are reported. Absorption, steady-state, and time-resolved fluorescence spectra of luminols exhibited substitution, solvent, and pH dependence. Singlet lifetimes have been determined by time-resolved laser flash spectroscopy. UV spectra in gas phase and DMSO solution were calculated by TD-DFT which revealed the existence of two low-energy excited singlet states with strong pH-sensitivity. © Springer Science+Business Media, LLC 2010. Source

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