Gas phase solvatochromic effects of phenol and naphthol photoacids

Abstract

A quantum chemical study of spectral shifts by single molecule solvation of phenol, α-naphthol, and β-naphthol is presented. The methods employed include the equation-of-motion coupled cluster, the similarity transformed equation-of-motion coupled cluster, single excitation configuration-interaction, and time-dependent density functional theory. Based on the calculations, there is no evidence that there is significant charge-transfer between the solute and the solvent. Instead, it appears that the observed solvation redshift is due to the nature of the excited state on the solute molecule.

Photochemistry of 1‐ and 2‐Naphthols and Their Water Clusters: The Role of 1ππ*(La) Mediated Hydrogen Transfer to Carbon Atoms

“…have studied the photodissociation of 1 with multimass ion imaging providing clear evidence for 1 πσ* mediated hydrogen detachment. From the theoretical side, the equation‐of‐motion (EOM) coupled cluster method has been employed to study the solvatochromatic shifts induced by a single ammonia molecule in 1 and 2 . In both systems, differences in the charge distribution between the solvated and unsolvated structures have been observed in the two lowest singlet excited states, 1 ππ*(L a ) and 1 ππ*(L b ).…”

“…However, no evidence of charge transfer between the solute and the solvent has been found. Interpreted in the context of excited state deactivation of 1 and 2 , the result of Melnichuk and Bartlett suggests that a third state, possibly the 1 πσ* state, may be involved in the dynamics . Indeed, Omidyan et al.…”

“…In this work, we report the first comparative analysis of the mechanisms of excited state deactivation of two prototypical photochemical systems: 1‐naphthol ( 1 ) and 2‐naphthol ( 2 ) as well as of their microsolvated water clusters. Numerous studies of isolated 1 and 2 , as well as their clusters with H 2 O (D 2 O), and NH 3 revealed complex excited state dynamics. Specifically, there exists a strong dependence on the isomer and solvent, as well as on the size and geometry of the cluster.…”

Solvatochromism of pyranine-derived photoacids

“…16,34,[59][60][61][62][63][64][65][66] A convenient approach to studying the interaction between a probe and the solvent using steady-state spectroscopy is the solvatochromic analysis. 44,[67][68][69][70][71][72] Absorption and emission wavelengths are collected in different media and correlated to solvent parameters from which solute properties can be deciphered. While absorption spectra are useful for the investigation of ground state properties, emission spectra contain information about the relaxed excited state.…”

Experimentally measured permanent dipoles induced by hydrogen bonding. The Stark spectrum of indole–NH3

“…18,19 Experimental quantifications of the hydrogen bonds involving molecules of approximately this size can provide an invaluable test of the current methods used to predict excited electronic state dynamics, both nuclear and electronic. 20,21 In this report, the hydrogen bond complexes formed between indole and ammonia were investigated with both low and high resolution fluorescence excitation spectroscopy in the gas phase. At low resolution, the indole-(NH 3 ) 1 (InA) and indole-(NH 3 ) 2 (InA 2 ) complexes were observed, along with intermolecular low frequency vibrations in the S 1 state.…”