A theoretical investigation of the interaction between substituted carbonyl derivatives and water: Open or cyclic complexes?

Abstract

The structures and binding energies of complexes between substituted carbonyl bases and water are the B3LYP/6-311++G(d,p) computational level. The calculations also include the proton affinity (PA) of the O of the C=O group, the deprotonation enthalpies (DPE) of the CH bonds along a natural bond orbital analysis. The calculations reveal that stable open C=O···H(w) O(w) as well as cyclic CH···O(w)H(w) ···O=C complexes are formed. The binding energies for the open complexes are linearly related to the PAs, whereas the binding energies for the cyclic complexes depend on both the PA and DPE. Different indicators of hydrogen bonds strength such as electron charge density, intramolecular and intermolecular hyperconjugation energy, occupation of orbitals, and charge transfer show significant differences between open and cyclic complexes. The contraction of the CH bond of the formyl group and the corresponding blue shift of the ν(CH) vibration are explained by the classical trans lone pair effect. In contrast, the elongation or contraction of the CH(3) group involved in the interaction with water results from the variation of the orbital interaction energies from the σ(CH) bonding orbital to the σ* and π* antibonding orbitals of the C=O group. The resulting blue or red shifts of the ν(CH(3)) vibrations are calculated in the partially deuterated isotopomers.

Theoretical investigation of the halogen bonded complexes between carbonyl bases and molecular chlorine

“…Proton affinities are slightly different for syn and anti protonation of the O atom of the CO bond, in agreement with earlier reports . From these data, a linear correlation between the interaction energies and proton affinity (PA) (kcal mol −1 ) can be calculated: …”

“…Lone pair directionality and linearity of the intermolecular bonds have been thoroughly discussed in the solid as well in the gaseous states . The complexes between the same carbonyl derivatives and water have been investigated in a recent theoretical work . Open as well cyclic complexes are formed.…”

Roles of H2O to hydrogen bonds, structure and strength of complexes of CH3CHS and H2O

“…[1,3] In a recent study, the complexes between acetaldehyde and some of its monofluorated derivatives with a water molecule show that water acts as a proton donor to create C=O•••H-O H-bond as well as a proton acceptor to form Csp2-H•••O H-bond. [9] Another study by A. K. Chandra and co-workers found a large blue-shift associated with the contraction of the Csp2-H length with an increase of the corresponding vibrational frequencies compared to the original monomer upon formation of Csp2-H•••O H-bonds in the CH3CHO•••nH2O (n=1-2) complexes. [10] However, the study has not deeply analyzed and explained the reason for the blue shift phenomenon of the ν(Csp2-H) vibration.…”

“…[10] The interaction energies of CH3CHO•••1H2O (from -14.9 to -15.6 kJ.mol -1 ) and RCHO•••1H2O (R=H, C2H5, CH2F) (from -12.2 to -15.2 kJ.mol -1 ) are more negative than the CH3CHS•••1H2O complexes. [9] Similarly, the interaction energies of CH3CHS•••2H2O (from -30.7 to -35.5 kJ.mol -1 ) are larger than those of CH3CHO•••2H2O (from -54.6 to -56.4 kJ.mol -1 ) [10] , indicating that when the O atom in CH3CHO is replaced by a S atom, the system becomes less stable. However, the interaction energies of CH3CHS•••1H2O (from -12.0 to -12.9 kJ.mol -1 ) is more negative than those of RCHX•••1CO2 (X=O, S; R=H, CH3) complexes (from -9.1 to -10.5 kJ.mol -1 ) [11] , proving that H2O greatly affects to the durability of the complex rather than CO2.…”

On the nature of halogen bonded complexes between carbonyl bases and chlorotrifluoromethane

“…This prompted us to compare the interaction energies with the basic properties of the ketones. The proton affinities (PA) calculated at the B3LYP-D3/6-311++G(d,p) level as well as the calculated and experimental ionization potentials (IP) of the ketones [56][57][58][59][60][61] are reported in Table 4.…”