Computational Study on a HS^– Sensing Reaction Utilizing a Pyrylium Derivative

Abstract

In this paper, we present a comprehensive computational study on the hydrogen sulfide sensing mechanism in aqueous solution using a pyrylium derivative. The possible sensing mechanisms were investigated under the neutral condition and acidic condition in the gas phase and in aqueous solution. The pyrylium–thiopyrylium transformation under the neutral condition is thermodynamically unfavorable, while it is greatly facilitated in the acidic condition catalyzed by a hydronium cation. In addition, the UV–vis absorption maxima of pyryliums and thiopyryliums were investigated at the TDDFT/B3LYP/6-31G+(d,p) level. The red shift of absorption maximum from unsubstituted pyrylium and thiopyrylium to dimethylamino-subisituted pyrylium and thiopyrylium as well as the red shift seen in the pyrylium–thiopyrylium transformation is interpreted in terms of the molecular orbital theory.

Donor and Ring‐Fusing Engineering for Far‐Red to Near‐Infrared Triphenylpyrylium Fluorophores with Enhanced Fluorescence Performance for Sensing and Imaging

“…2,4,6‐Triphenylpyrylium salt ( TPP , Figure a), a heterocyclic system with unique photophysical properties, shows great potential for sensor applications . However, some inherent limitations of the TPP core scaffold, such as instability in water, short emission wavelength, and low quantum yields, hinder its application in biological imaging and probe development.…”

“…Design 2,4,6-Triphenylpyrylium salt (TPP,F igure 1a), ah eterocyclic system with unique photophysical properties, shows great po-tential for sensor applications. [38,[40][41][42] However,s ome inherent limitations of the TPP core scaffold, such as instability in water, short emission wavelength, and low quantum yields, hinder its application in biological imaging and probe development. Densityf unctional theory (DFT) calculations indicated that the p electrons in the LUMO of TPP are delocalized over the entire p-conjugated 2,4,6-triphenylpyrylium framework, whereas the HOMO is mostly localized on the 2,6-phenyl substituents (Figure 1b).…”

Roles of Water Molecules and Counterion on HS– Sensing Reaction Utilizing a Pyrylium Derivative: A Computational Study

“…The transition states have also been verified by pseudo-IRC (intrinsic reaction coordinate) calculations. 77,78 The 6-31G(d) basis set is a good compromise between efficiency and accuracy 64,79,80 and has been proven to reproduce well the molecular parameters. The further expansion of the basis set such as 6-311+G(d,p) has less impact on the accuracy of the molecular geometries and activation energy.…”

“…In our previous study, 64 the pyrylium−thiopyrylium transformation under acidic condition was modeled by involving one hydronium ion to the reaction coordinate; its activation energy was reported to be 40.2 kcal/mol. This high activation energy indicates that the pyrylium−thiopyrylium transformation involving only a hydronium ion is kinetically unfavorable.…”

A derivatization approach using pyrylium salts for the sensitive and simple determination of sulfide in spring water by high performance liquid chromatography

“…1). For instance, for LN1 such transformation involves a red-shift of the absorption band from 540 nm for the pyrylium derivative to 580 nm for LN3 [28]. This is a highly selective reaction and only hydrogen sulfide and sulfide anions are able to induce such a color change from magenta to blue.…”