11B NMR Chemical Shift Predictions via
Density Functional Theory and Gauge-Including Atomic Orbital Approach:
Applications to Structural Elucidations of Boron-Containing Molecules
11B nuclear magnetic resonance (NMR) spectroscopy is
a useful tool for studies of boron-containing compounds in terms of
structural analysis and reaction kinetics monitoring. A computational
protocol, which is aimed at an accurate prediction of 11B NMR chemical shifts via linear regression, was proposed based on
the density functional theory and the gauge-including atomic orbital
approach. Similar to the procedure used for carbon, hydrogen, and
nitrogen chemical shift predictions, a database of boron-containing
molecules was first compiled. Scaling factors for the linear regression
between calculated isotropic shielding constants and experimental
chemical shifts were then fitted using eight different levels of theory
with both the solvation model based on density and conductor-like
polarizable continuum model solvent models. The best method with the
two solvent models yields a root-mean-square deviation of about 3.40
and 3.37 ppm, respectively. To explore the capabilities and potential
limitations of the developed protocols, classical boron–hydrogen
compounds and molecules with representative boron bonding environments
were chosen as test cases, and the consistency between experimental
values and theoretical predictions was demonstrated.