Insights into the cooperativity between multiple interactions of dimethyl sulfoxide with carbon dioxide and water

Abstract

Interactions of dimethyl sulfoxide with carbon dioxide and water molecules which induce 18 significantly stable complexes are thoroughly investigated. An addition of CO 2 or H 2 O molecules into the DMSOÁ Á Á1CO 2 and DMSOÁ Á Á1H 2 O systems leads to an increase in the stability of the resulting complexes, in which it is larger for a H 2 O addition than a CO 2 . The overall stabilization energy of the DMSOÁ Á Á1,2CO 2 is mainly contributed by the S=OÁ Á ÁC Lewis acid-base interaction, whereas the O − HÁ Á ÁO hydrogen bond plays a significant role in stabilizing complexes of DMSOÁ Á Á1,2H 2 O and DMSOÁ Á Á1CO 2 Á Á Á1H 2 O. Remarkably, the complexes of DMSOÁ Á Á2H 2 O are found to be more stable than DMSOÁ Á Á1CO 2 Á Á Á1H 2 O and DMSOÁ Á Á2CO 2 . The level of the cooperativity of multiple interactions in ternary complexes tends to decrease in going from DMSOÁ Á Á2H 2 O to DMSOÁ Á Á1CO 2 Á Á Á1H 2 O and finally to DMSOÁ Á Á2CO 2 . It is generally found that the red shift of the O − H bond involved in an O − HÁ Á ÁO hydrogen bond increases while the blue shift of a C − H bond in a C − HÁ Á ÁO hydrogen bond decreases when a cooperative effect occurs in ternary complexes as compared to those of the corresponding binary complexes.

Importance of water and intramolecular interaction governs substantial blue shift of Csp2–H stretching frequency in complexes between chalcogenoaldehydes and water

“…The C sp 2 –H stretching frequency blue-shifts of 81–96 cm −1 and 53 cm −1 in the C sp 2 –H⋯O H-bonds were indeed reported for the interactions of formaldehydes and thioformaldehydes with formic acid and nitrosyl hydride. 36,73 It is noteworthy that smaller magnitudes of the C sp 3 –H stretching frequency blue-shifts were suggested for Cl 3 CH⋯NCCH 3 (8.7 cm −1 ), 30 F 3 CH⋯OH 2 (20.3–32.3 cm −1 ), 38 CHX 3 ⋯NH 2 Y (X = F, Cl; Y = H, F, Cl, Br) (9.4–36.3 cm −1 ), 74 and DMSO⋯H 2 O/CO 2 (8.4–44.5 cm −1 ), 75 despite the lower polarity of C sp 3 –H than C sp 2 –H covalent bond. These results indicate the important role of adding one or more H 2 O molecules into the binary systems, which contributes to a significant increase of C sp 2 –H stretching frequencies in C sp 2 –H⋯O H-bonds.…”

Thermodynamic and Kinetic Studies of the Radical Scavenging Behavior of Hydralazine and Dihydralazine: Theoretical Insights

“…A quantum mechanics-based test for the overall free radical scavenging activity (QM-ORSA) protocol was used for the kinetic calculations in the gas phase as well as in polar and nonpolar solvents; for the latter, the solvation model density (SMD) method was used. , The rate constants were computed according to the transition state theory (at 298.15 K, 1 M standard state) by using eq (the detailed method can be found in Table S5) − where σ is the reaction symmetry number, , κ represents the tunneling correction which was calculated using the Eckart barrier, k B is the Boltzmann constant, h is the Planck constant, and Δ G ⧧ is the Gibbs free energy of activation.…”

Theoretical Aspects of Nonconventional Hydrogen Bonds in the Complexes of Aldehydes and Hydrogen Chalcogenides

“…A large number of C sp3 −H blue shifts of stretching frequency have been reported both experimentally and theoretically. 39,48,49 The blue shifts of the C sp3 −H stretching frequency in the complex of CHX 3 − NH 2 Y (X = F, Cl; Y = H, F, Cl, and Br) (9−36 cm −1 ), 83 DMSO...H 2 O/CO 2 (8−44 cm −1 ), 84 and F 3 CH...OH 2 (20−32 cm −1 ) 34 were reported. In 2019, a slight C sp3 −H blue shift of ∼9 cm −1 was observed by the Fourier transform infrared spectroscopic exp eriment in the binary system Cl 3 CH...NCCH 3 .…”