Wydział Chemii

Massimiliano Pasquini

Nicola Schiccheri

Giovanni Piani

Giangaetano Pietraperzia

Maurizio Becucci

Małgorzata Biczysko

Michele Pavone

Vincenzo Barone

2007

Journal of Physical Chemistry A

111

12363-12371

10.1021/jp0757558

Naukowa

Angielski

Artykuł

Resonance enhanced multiphoton ionization and rotationally resolved S₁ ← S₀ electronic spectra of the anisole−²H₂O complex have been obtained. The experimental results are compared with high level quantum mechanical calculations and with data already available in the literature. Quite surprisingly, the equilibrium structure of the anisole−²H₂O complex in the S₀ state shows some non-negligible differences from that of the isotopomer anisole− ¹H₂O complex. Actually, the structure of the deuterated complex is more similar to the corresponding structure of the anisole−¹H₂O complex in the S₁ state. In anisole−water, two equivalent H(D) atoms exist as revealed by line splitting in the rotationally resolved spectra. It is possible to suggest a mechanism for the proton/deuteron exchange ruled by a bifurcated transition state for the exchange reaction, with both water hydrogen atoms interacting with the anisole oxygen atom. From the analysis of all of the available experimental data and of computational results, we can demonstrate that in the S₁ excited state the hydrogen bond in which the water molecule acts as an acid is weaker than in the electronic ground state but is still the principal interaction between water and the anisole molecules.

http://dx.doi.org/10.1021/jp0757558

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