A New Excitation Sequence to Observe the PASADENA Effect

Abstract

Abstract In recent years, a new NMR technique called p ara h ydrogen- i nduced p olarization (PHIP) has been developed to study homogeneous catalytic hydrogenations in situ. This method uses parahydrogen as a reagent and olefins or acetylenes as the substrates, leading to a large signal enhancement in the resulting proton spectra. Until now, in order to observe such enhanced proton spectra, a 45° pulse was required for acquisition, but in this paper, there is introduced a simple selective excitation and detection scheme which provides a more versatile and flexible means for observing signals enhanced by the PHIP technique. As examples, how a 1D TOCSY experiment and how a multistage selective HOHAHA polarization transfer can be performed on a PHIP system are illustrated.