Unexpected solvent effects on the UV/Vis absorption spectra of o -cresol in toluene and benzene: in contrast with non-aromatic solvents

Abstract

Cresol is a prototype molecule in understanding intermolecular interactions in material and biological systems, because it offers different binding sites with various solvents and protonation states under different pH values. It is found that the UV/Vis absorption spectra of o-cresol in aromatic solvents (benzene, toluene) are characterized by a sharp peak, unlike the broad double-peaks in 11 non-aromatic solvents. Both molecular dynamics simulations and electronic structure calculations revealed the formation of intermolecular π-complexation between o-cresol and aromatic solvents. The thermal movements of solvent and solute molecules render the conformations of o-cresol changing between trans and cis isomers. The π-interaction makes the cis configuration a dominant isomer, hence leading to the single keen-edged UV/Vis absorption peak at approximately 283 nm. The free conformation changes between trans and cis in aqueous solution rationalize the broader absorption peaks in the range of 260–280 nm. The pH dependence of the UV/Vis absorption spectra in aqueous solutions is also rationalized by different protonation states of o-cresol. The explicit solvent model with long-ranged interactions is vital to describe the effects of π-complexation and electrostatic interaction on the UV/Vis absorption spectra of o-cresol in toluene and alkaline aqueous (pH > 10.3) solutions, respectively.

Revealing Donor–Acceptor Interaction on the Printed Active Layer Morphology and the Formation Kinetics for Nonfullerene Organic Solar Cells at Ambient Conditions

“…[24][25][26] Substantial research proved that the host solvent played a dominant role in the morphology control of the active layer, which influenced the performance of the final devices. [27][28][29] By carefully tuning the print parameters, Zhao et al reported the effects of halogenated and hydrocarbon solvents on PDBD-T-2F:BTP-4F active layer based BHJ OSC. A higher degree of crystallinity with a more minor phase separation structure was observed in ortho-xylene processed thin films, yielding the promising champion efficiency of 15.6%.…”

Acid selective pro-dye for cellular compartments

“…Similar effects were reported also by Zheng et al . 19 As a consequence both SC2 and BC15 have no maxima below 280 nm in those solvents. The emission spectra, however, are much more dependent on the polarity because the values of the fluorescence maxima vary more significantly for both compounds.…”

UV-Visible Absorption Spectra of Solvated Molecules by Quantum Chemical Machine Learning

“…The absorption spectrum of 1,4-anisidine was measured at pH= 6.0, while in our FPMD simulations molecules solvated in aqueous solution at neutral pH, and this difference may cause a shift in the UV-visible absorption. 70,77 The QC spectra were obtained by averaging only a few hundred frames for each molecule.…”