O–H···S Hydrogen Bonds Conform to the Acid–Base Formalism

Abstract

Hydrogen bonding interaction between the ROH hydrogen bond donor and sulfur atom as an acceptor has not been as well characterized as the O-H···O interaction. The strength of O-H···O interactions for a given donor has been well documented to scale linearly with the proton affinity (PA) of the H-bond acceptor. In this regard, O-H···O interactions conform to the acid-base formalism. The importance of such correlation is to be able to estimate molecular property of the complex from the known thermodynamic data of its constituents. In this work, we investigate the properties of O-H···S interaction in the complexes of the H-bond donor and sulfur containing acceptors of varying proton affinity. The hydrogen bonded complexes of p-Fluorophenol (FP) with four different sulfur containing acceptors and their oxygen analogues, namely H2O/H2S, MeOH/MeSH, Me2O/Me2S and tetrahydrofuran (THF)/tetrahydrothiophene (THT) were characterized in regard to its S1-S0 excitation spectra and the IR spectra. Two-color resonantly enhanced multiphoton ionization (2c-R2PI), resonant ion-dip infrared (RIDIR) spectroscopy, and IR-UV hole burning spectroscopic techniques were used to probe the hydrogen bonds in the aforementioned complexes. The spectroscopic data along with the ab initio calculations were used to deduce the strength of the O-H···S hydrogen bonding interactions in these system relative to that in the O-H···O interactions. It was found that, despite being dominated by the dispersion interaction, the O-H···S interactions conform to the acid-base formalism as in the case of more conventional O-H···O interactions. The dissociation energies and the red shifts in the O-H stretching frequencies correlated very well with the proton affinity of the acceptors. However, the O-H···S interaction did not follow the same correlation as that in the O-H···O H-bond. The energy decomposition analysis showed that the dissociation energies and the red shifts in the O-H stretching frequencies follow a unified correlation if these two parameters were correlated with the sum of the charge transfer and the exchange component of the total binding energy.

Spectroscopic and Ab Initio Investigation of C−H⋅⋅⋅N Hydrogen‐Bonded Complexes of Fluorophenylacetylenes: Frequency Shifts and Correlations

“…In an effort to comprehend this behavior, the redshift in the acetylenic C−H stretching frequencies were plotted against other components of the SAPT2 interaction energy, such as induction, dispersion, and exchange repulsion, and the results are presented in Figure A–C. Similar correlations between various energy components for a variety of hydrogen‐bonded systems have been reported in the literature . It can be seen from Figure that the frequency shifts are linearly correlated with induction energy, which is a second‐order electrostatic effect.…”

“…Similar correlations between various energy componentsfor avariety of hydrogen-bondeds ystems have been reported in the literature. [45][46][47][48][49][50] It can be seen from Figure 7t hat the frequency shifts are linearly correlated with induction energy,w hich is as econd-order electrostatic effect. The linear correlation suggestst hat even second-order electrostatic effects can influence the vibrational frequency shift.…”

Absorptive Desulfurization of Model Biogas Stream Using Choline Chloride-Based Deep Eutectic Solvents

“…All characteristic bands that can be attributed to DMDS (2909.32 cm −1 -δs (CH) stretch, 1411.73 cm −1 -δas (CH 3 ) def., 1302.68 cm −1 -δs (CH 3 ) def., 692.82 cm −1 -C-S stretch, 540.96 cm −1 -S-S stretch) are visible in the ChCl:Ph-DMDS spectrum [56], which indicates the creation of the DES-DMDS complex (Figure 3a). Theoretically, in the absorptive DMDS removal process, both sulfur atoms can act as a donor in S-H···π and as an acceptor in O-H···S and C-H···S interactions [57][58][59]. However, on the FT-IR spectra, there are no shifts corresponding to this type of interaction.…”

Infrared and Raman Measurements of Halogen Bonding in Cryogenic Solutions

“…For hydrogen-bonded complexes, for example, attempts have been made [147][148][149][150]] to plot the X-H stretching vibrational shift vs the experimentally determined complexation enthalpy. Figure 43 shows the correlation of the experimental complexation enthalpies and theoretical values obtained by correcting the ab initio energies for zero-point vibrational, thermal and solvent influences.…”