Wydział Chemii

Agnieszka Krzemińska

Małgorzata Biczysko

Katarzyna Pernal

Michał Hapka

2024

Journal of Physical Chemistry A

128

8816-8824

10.1021/acs.jpca.4c04928

Naukowa

Angielski

Artykuł

Binary complexes of anisole have long been considered paradigm systems for studying microsolvation in both the ground and electronically excited states. We report a symmetry-adapted perturbation theory (SAPT) analysis of intermolecular interactions in anisole-water and anisole-ammonia complexes within the framework of the multireference SAPT(CAS) method. Upon the S₁ ← S₀ electronic transition, the hydrogen bond in the anisole-water dimer is weakened, which SAPT(CAS) shows to be determined by changes in the electrostatic energy. As a result, the water complex becomes less stable in the relaxed S₁ state despite decreased Pauli repulsion. Stronger binding of the anisole-ammonia complex following electronic excitation is more nuanced and results from counteracting shifts in the repulsive (exchange) and attractive (electrostatic, induction and dispersion) forces. In particular, we show that the formation of additional binding N-H···π contacts in the relaxed S₁ geometry is possible due to reduced Pauli repulsion in the excited state. The SAPT(CAS) interaction energies have been validated against the coupled cluster (CC) results and experimentally determined shifts of the S₁ ← S₀ anisole band. While for the hydrogen-bonded anisole-water dimer SAPT(CAS) and CC shifts are in excellent agreement, for ammonia SAPT(CAS) is only qualitatively correct.

Colloids, Excited States, Interaction Energies, Mathematical Methods, Oligomers

CC-BY

http://dx.doi.org/10.1021/acs.jpca.4c04928

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