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

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 (σ_calc); 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.