✍ Scribed by Josef Heinzer; Jean F. M. Oth
No coin nor oath required. For personal study only.
Iterative least‐squares lineshape fitting of ^1^H‐decoupled ^13^C‐DNMR. spectra is advantageously used for the investigation of symmetrical or asymmetrical intramolecular (two‐structure) exchange processes. The least‐squares procedure adopted allows the following parameters to be either optimized by computer or kept constant (according to experimental conditions): the nuclei populations (taking into account line intensity effects resulting from differences in spin‐lattice relaxation times and/or Overhauser enhancements), the corresponding chemical shifts and natural linewidths (characterizing the sites undergoing exchange), the fractional population of one structure (in the case of asymmetrical exchange), one of the chemical rates, the base‐line position, and the base‐line tilt. The relative sensitivity of the lineshape with respect to the fitted parameters as well as the importance of correlations among these parameters have been investigated and tested with examples. The reliability of the kinetic parameters as obtained by the iterative least‐squares lineshape fitting procedure is discussed.
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## Abstract ^13^C FT n.m.r. spectra were obtained from borates of methyl α‐D‐glucopyranoside, triethylboron, sodium tetraphenylboron and 1‐butaneboronic acid employing a simultaneous ^1^H and ^11^B decoupling network. The effectiveness of the system was evident using the three latter organoboron co
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