A Preorganized
Hydrogen Bond Network and Its Effect
on Anion Stability
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Abstract
Rigid
tricyclic locked in all axial 1,3,5-cyclohexanetriol derivatives
with 0–3 trifluoromethyl groups were synthesized and photoelectron
spectra of their conjugate bases and chloride anion clusters are reported
along with density functional computations. The resulting vertical
and adiabatic detachment energies span 4.07–5.50 eV (VDE) and
3.75–5.00 (ADE) for the former ions and 5.60–6.23 eV
(VDE) and 5.36–6.00 eV (ADE) for the latter species. These
results provide measures of the anion stabilization due to the hydrogen
bond network and inductive effects. The latter mechanism is found
to be transmitted through space via hydrogen bonds, and the presence
of three ring skeleton oxygen atoms and up to three trifluoromethyl
groups enhance the ADEs by 1.61–2.88 eV for the conjugate bases
and 1.01–1.60 eV for the chloride anion clusters. Computations
indicate that the most favorable structures of the latter complexes
have two hydrogen bonds to the chloride anion and one bifurcated interaction
between the remote OH substituent and the two hydroxyl groups that
directly bind to Cl<sup>–</sup>