Do deuteriums form stronger CH-π interactions?
The D/H isotope effect for the CH-π interaction was studied experimentally and computationally. First, a series of molecular balances that are very sensitive to changes in the strength of the CH-π interactions in solution were designed. Balances with deuterated and non-deuterated alkyl groups were synthesized, and their intramolecular CH-π interactions were compared. The geometries of their intramolecular CH-π and CD-π interactions were characterized in the solid state by X-ray analysis, and the strength of each interaction was characterized in solution by the folded/unfolded ratio as measured by (1)H NMR spectra. Second, the relative strengths of the CH-π and CD-π interactions were also assessed computationally using dispersion-corrected DFT (PDE-D2/6-31+G*). No significant differencee was observed in either the experimental or theoretical studies, indicating that the D/H isotope effect for the CH-π interaction is either very small or nonexistent.
Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA.
Chen
C
Zhao
Robert M
RM
Parrish
Mark D
MD
Smith
Perry J
PJ
Pellechia
C David
CD
Sherrill
Ken D
KD
Shimizu