NMR and X‑ray Studies of Hydrogen Bonding for Amide-Containing Silanediols

The synthesis, isolation, and hydrogen-bonding properties
of a
series of amide-containing silanediols are described, including an
enantioenriched silanediol. By incorporation of a 2,4,6-trimethylphenyl
(mesityl) group, these functionalized silanediols are isolable by
column chromatography and stable in the presence of standard acids
(e.g., AcOH) and bases (e.g., NH4OH). NMR spectroscopy
and X-ray crystallography provide evidence for the conformational
rigidity and binding properties of amido-silanediols based on the
parameters (e.g., sterics,
hybridization, and ring size of hydrogen bonding) that affect intra-
and intermolecular hydrogen bonding. Pyridine binding studies demonstrate
that these conformational effects have implications for the existence
of single versus multiple modes of hydrogen bonding.