Prediction of 89Y NMR Chemical Shifts in Organometallic Complexes with Density Functional Theory

2006-11-06T00:00:00Z (GMT) by Rosemary E. White Timothy P. Hanusa
Organometallic and coordination compounds containing yttrium are usefully characterized with 89Y NMR spectroscopy (I = −1/2, 100% nat. abund.). Even though the qualitative contributions of various ligand groups to the yttrium NMR chemical shift have been known for some time, attempts to predict the shifts quantitatively have been limited. In the present work, a variety of organoyttrium complexes containing cyclopentadienyl, alkyl, hydride, and aryloxide ligands have been optimized with density functional theory methods. The optimized structures were used with the gauge-including atomic orbital (GIAO) method to calculate the corresponding 89Y NMR magnetic shielding values (σcalc); the latter were linearly scaled to adjust the fit with observed chemical shifts. Agreement between predicted and experimental 89Y NMR shifts is typically within ±70 ppm (∼5% of the ca. 1300 ppm shift range). 89Y NMR calculations were used to provide supporting evidence for the existence of the bulky triallyl complex Y[1,3-(SiMe3)2C3H3]3.