Crystal Structure Refinement Using Chemical Shifts

Abstract

A review is given on the crystal structure detn. using NMR chem. shifts. To solve crystal structures by NMR, the following computational requirements must be fulfilled: (i) the energy of a unit cell including the influence of the lattice must be calcd., (ii) extremely fast methods are necessary to calc. the chem. shifts, and (iii) the derivations of the chem. shifts must be evaluated with respect to the at. coordinates. Here, the appropriate methods are introduced based on the bond polarization theory, and some application examples are given. The application examples deal with the refinement of proton positions using the COSMOS-NMR force field and with the structure detn. of cellulose polymorphs from 13C chem. shifts. [on SciFinder(R)]