Characterization of Reactive Intermediates by Diffusion-Ordered NMR Spectroscopy: A Snapshot of the Reaction of 13CO2 with [Cp2Zr(Cl)H]

Abstract

A new tool for the investigation of reaction intermediates: By using DOSY NMR spectroscopy, the presence of a binuclear complex 1 as the key intermediate on the way to 2 (see spectrum) was detected for the first time in the title reaction.

Ion pairing using PGSE diffusion methods

“…In recent times the two-dimensional DOSY variant (diffusion ordered spectroscopy) occasionally referred to as ''NMR chromatography'', for its ability to facilitate and visualize the resolution and assignment of complex mixtures, has become increasingly popular [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61]. There is no question as to both the elegance and potential of this methodology; however, as the above discussion (hopefully) indicates, concentration effects can be important.…”

Accurate DOSY measure for out-of-equilibrium systems using permutated DOSY (p-DOSY)

“…However in this approach, the DOSY measurements are supposed to be rapid compared to the kinetic rates, and there is no compensation for the unavoidable bias in the diffusion coefficient measure. To our knowledge, the DOSY studies performed so far on out-of-equilibrium systems [22][23][24][25][26] have not taken into account the analytical bias caused by concentration variations.…”

Studies on self-aggregation of anthracycline drugs by restrained molecular dynamics approach using nuclear magnetic resonance spectroscopy supported by absorption, fluorescence, diffusion ordered spectroscopy and mass spectrometry

“…A change in chemical shift does not provide sufficient indication about the strength of interaction between the components, which could be due to other effects influencing the chemical structure. On the other hand DOSY plots clearly manifest strength of hydrogen bonding [17]/ligand binding [18] and self-association [19] which may help in structure elucidation. Also, spins in two different chemical surroundings may be identified separately depending upon their diffusion coefficient, diffusion time and relative populations of spins [20].…”