Lanthanide shift reagents solution equilibria

In the determination of the relative configurations in acyclic diastereomers with the aid of lanthanide shift reagents (LSR), conformation plays a major role and the equilibrium of rotamers in the complex may differ from that of the pure solute. 

Chemical equilibrium in solution has been a problem of long standing interest. Here we will present the procedures and criteria for the characterization of weak molecular complexes, (Deranleau, 1969a, 1969b Maier and Drago, 1972), as adapted in our laboratory to the problem of shift reagents, Lenkinski, Elgavish and Reuben (1978). The observed lanthanide induced shift, S, is a sum of two contributions... 

---