Wydział Chemii

Marek Ilczyszyn

Marcin P. Selent

Maria M. Ilczyszyn

2012

Journal of Physical Chemistry A

116

3206-3214

10.1021/jp210670k

Naukowa

Angielski

Artykuł

In the β-hydroquinone (β-HQ)–Xe crystal, the Xe guest is placed between two hexagonal rings of coupled [···O–H···O−]₆ H-bonds. This clathrate is treated as the model for monitoring the H-bonding system with the Xe participation. Three kinds of isotope effects due to the H/D substitution in the [···O–H···O−]₆ bonds are considered: (i) structural changes in the clathrate (X-ray diffraction), (ii) variations of ¹²⁹Xe NMR signal of the guest (CP MAS), and (iii) variations of selected vibrations of the host (IR). This study predicts subtle inclination of every other hydroxyl group of the [···O–H···O−]₆ rings into the Xe atom and formation of six Xe···H–O pairs in every cage, the frequency shift of the γOH mode due to these contacts, −ΔγOH(Xe···H) > 74 cm^–1, as well as the enthalpy formation, −ΔH(Xe···H) > 6–8 kJ mol^–1. Our IR results reveal a tendency of the Xe atom to form the H-bond-like network inside its cage and much weaker Xe···D–O interactions in the H/D substituted crystal. The ¹²⁹Xe NMR results do not reflect this kind of interactions due to averaging of the ¹²⁹Xe shielding phenomena, probably. We also predict elongation of the O···O distances due to the β-HQ–Xe crystal heating and the Xe escape.

https://doi.org/10.1021/jp210670k

https://www.acs.org/content/acs/en.html