Polarized C-H Groups as Novel Hydrogen-Bond Donors in Hydryl-F-alkyl Esters: Unequivocal Examples for the "Pinchas Effect"

Article abstract of DOI:10.1021/jo00112a021

1H NMR and IR spectral evidence for a C-H...O hydrogen bonds in 1-<2-hydryl-F-adamantyl> trifluoroacetate and 1,3-<2-hydryl-F-adamantyl> bis(trifluoroacetate) are presented.Evidence indicating a three-center hydrogen bond in 1,3-<2-hydryl-F-adamantyl> bis(trifluoroacetate) is also presented.Both compounds, despite otherwise normal 1H NMR chemical shift displacements and carbonyl stretching frequency depressions, show strong increases in C-H stretching frequencies related to hydrogen-bond interactions (the "Pinchas Effect").