1 research outputs found
Raman, Surface-Enhanced Raman, and Density Functional Theory Characterization of (Diphenylphosphoryl)(pyridin-2‑, -3‑, and -4-yl)methanol
This work presents near-infrared
Raman spectroscopy (FT-RS) and
surface-enhanced Raman scattering (SERS) studies of three pyridine-α-hydroxymethyl
biphenyl phosphine oxide isomers: (diphenylphosphoryl)(pyridin-2-yl)methanol
(α-Py), (diphenylphosphoryl)(pyridin-3-yl)methanol (β-Py),
and (diphenylphosphoryl)(pyridin-4-yl)methanol (γ-Py) adsorbed
onto colloidal and roughened in oxidation–reduction cycles
silver surfaces. The molecular geometries in the equilibrium state
and vibrational frequencies were calculated by density functional
theory (DFT) at the B3LYP 6-311G(df,p) level of theory. The results
imply that the most stable structure of the investigated molecules
is a dimer created by two intermolecular hydrogen bonds between the
H atom of the α-hydroxyl group (in up (HO<sub>U</sub>) or down
(HO<sub>D</sub>) stereo bonds position) and the O atom of tertiary
phosphine oxide (O) of the two monomers. Comparison the FT-RS
spectra with the respective SERS spectra allowed us to predict the
orientation of the hydroxyphosphonate derivatives of pyridine that
depends upon both the position of the substituent relative to the
ring N atom (in α-, β-, and γ-position, respectively)
and the type of silver substrate