1,721,102 research outputs found
Nitroxide paramagnet-induced para-ortho conversion and nuclear spin relaxation of H-2 in organic solvents
No full textThe kinetics of para-ortho conversion and nuclear spin relaxation of H-2 in chloroform-d(1), were investigated in the presence of nitroxides as paramagnetic catalysts. The back conversion from parahydrogen (p-H-2) to ortho-hydrogen (o-H-2) was followed by NMR by recording the increase in the intensity of the signal of o-H-2 at regular intervals of time. The nitroxides proved to be hundreds of times more effective at inducing relaxation among the spin levels of o-H-2 than they are in bringing about transitions between p-H-2 and the levels of o-H-2. The value of the encounter distance d between H-2 and the paramagnetic molecule, calculated from the experimental bimolecular conversion rate constant k(0), using the Wigner theory of para-ortho conversion, agrees perfectly with that calculated from the experimental relaxivity R-1 using the force free diffusion theory of spin-lattice relaxation
Tempo Radicals as EPR Probes to Monitor the adsorption of Different Species into X Zeolite
No full textSolid state NMR and EPR study of Intracrystalline vs. External Surface Adsorption of Photoreactive Ketones in Pentasil Zeolites
No full textSupramolecular Structure and Dynamics of Organic Molecules Adsorbed on the External Surface of MFI Zeolites. A Direct and Indirect Computational EPR Analysis
No full textTime Resolved CW-EPR Spectroscopy of Powdered Samples: Electron Spin Polarization of a Nitroxyl Radical Adsorbed on NaY Zeolite, Generated by the Quenching of Excited Triplet Ketones
No full textNitroxide Labeled Ru(II)-Polypyridyl Complexes as EPR Probes to Study Organized Systems: 1. Micellar Solutions and Micellization of Sodium Alkyl Sulfates
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An EPR and Fluorescence Depolarization Study of Intermolecular Interactions of Dendrimers at Medium and Highly Concentrated Aqueous Solutions
No full textAggregational Process of the Positively Charged Surfactants - CTAC and CAT16 - in the Presence of Starburst Dendrimers: an EPR Study
No full textCharacterization of Starburst Dendrimers by the EPR Technique. Copper(II) Ions Full Generation Dendrimers
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