Parallel NMR Based on Solution Magnetic-Susceptibility Differences. Application to Isotopic Effects on Self-Diffusion
摘要:
Different susceptibility NMR line shifts can be induced in distinct liquid solutions by dissolving different concentrations of complexes of paramagnetic lanthanide Ln(3+) ions. We show how these solutions, put in capillaries, can be simultaneously studied with a standard high-resolution spectrometer. After theoretical justification the method is illustrated by an investigation of the effects or H/D substitution on self-diffusion in heavy water. Non-Stokesian effects are observed.
A meta-selective C−H carboxylation reaction of 1,1-diarylethylene derivatives with CO2 by using a rhodium catalyst with NaOiPr as a stoichiometric reductant has been achieved. Together with hydrogenation of the ethylene moiety, a carboxyl group was introduced to the meta-position of the aryl ring with high selectivity over the ortho-positions. Experimental and computational mechanistic studies indicate