Lanthanide Induced Shifts as a Conformational Probe for o,o,o'o'-Tetrasubstituted Diphenyls

Article abstract of DOI:10.1002/mrc.1270130306

The 1H NMR spectra of several symmetrical diphenyls, having two unlike substituents on the ortho positions of each aromatic ring, were determined in the presence of Eu(fod)3 and of Pr(fod)3.The lanthanide induced shifts were used to establish the more probable conformation of the molecules, as deduced from computer calculations assuming pseudocontact interactions.It was found that the two like groups are in opposite conformation and that the inter-ring angles are in the order of 15-35 deg.