Solute - solvent repulsion effects on the absorption spectra of anthracene in n-hexane investigated under high pressure

Kinga Roszak; Andrzej Maciejewski; Andrzej Katrusiak; Ewa Krystkowiak

doi:10.1016/j.saa.2023.122822

Solute - solvent repulsion effects on the absorption spectra of anthracene in n-hexane investigated under high pressure

Spectrochim Acta A Mol Biomol Spectrosc. 2023 Oct 15:299:122822. doi: 10.1016/j.saa.2023.122822. Epub 2023 May 7.

Authors

Kinga Roszak¹, Andrzej Maciejewski¹, Andrzej Katrusiak¹, Ewa Krystkowiak²

Affiliations

¹ Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland.
² Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland. Electronic address: ewakryst@amu.edu.pl.

PMID: 37182252
DOI: 10.1016/j.saa.2023.122822

Abstract

The band positions in the UV-VIS absorption spectra of compressed solution of anthracene in n-hexane significantly depend not only on the dispersive but also on the repulsive solute-solvent interactions, what has so far been omitted. Their strength is determined not only by the solvent polarity but also by Onsager cavity radius changing with pressure. The results obtained for anthracene show that repulsive interactions should be included in the interpretation of barochromic and solvatochromic results of aromatic compounds. We show that the barochromic studies in the liquid solvent can be an alternative to solvatochromic studies, e.g. to determine the polarizability of organic molecules in the electronic excited state. The pressure-induced polarity change in n-hexane exceeds that induced by the exchange of n-alkane solvents between n-pentane and n-hexadecane.

Keywords: Anthracene; Barochromism; High pressure; Repulsive and dispersive interactions; Solvatochromism; UV–VIS spectroscopy.