H-1-NMR LANTHANIDE-INDUCED SHIFT INVESTIG ATIONS OF HIGHLY FLEXIBLE MOLECULES .3. APPLICATIONS TO ALCOHOLS, ALDEHYDES, ESTERS, AND AMINES

Two new methods (RANDOM-LIS and STEED-LIS) with random selection of up to ten dihedral angles were applied for the determination of preferre d conformers of flexible molecules (alcohols, aldehydes, esters, and a mines, respectively, with only one coordination site) by LIS studies. The results proved to be useful. The preferred complexation conformati on was detected only in cases where conformational changes of the subs trate took place to improve complexation to the LIS reagent. Force fie ld calculations (RANDOM-PIMM) and Simple Hard Sphere Model calculation s (RANDOM-SHSM and STEED-SHSM), using the same algorithm of randomly v arying the dihedral angles, support the results obtained.