Theoretical investigation of the conformation, acidity, basicity and hydrogen bonding ability of halogenated ethers

Abstract

MP2/6-311++G(d,p) calculations have been carried out to investigate the conformation, protonation and the hydrogen bonding interactions with water of several halogenated ethers (CH(3)OCH(2)Cl, CH(2)ClOCH(2)Cl, CH(3)OCHCl(2), CHFClOCHF(2)). The optimized geometries, ν(CH) harmonic vibrational frequencies and the SAPT decomposition of the interaction energies are studied. The interaction with one water molecule gives several stable structures characterized by O(w)H(w)...O and CH...O(w) hydrogen bonds or by O...Cl halogen bonding. The MP2/CBS calculated binding energies of different complexes between the halogenated ethers and water vary between 1.7 and 7.7 kcal mol(-1). The energies of these structures are discussed as a function of the proton affinity of the ethers and the deprotonation enthalpy of the CH bonds. The contraction of the CH bonds and blue shifts of the corresponding stretching vibrations in the O-protonated ethers and their O...H(w)O(w) complexes are compared. A natural bond orbital analysis has revealed that substitution of the H atoms by one or several halogen atoms has a great influence on the hyperconjugative effects from the two non-equivalent O lone pairs to relevant antibonding orbitals, and the subsequent geometry of the hydrogen bonded complexes.

An exploration of the ozone dimer potential energy surface

“…Electrostatic attractions are typically supplemented by charge transfer from the lone pair(s) of one atom into the σ * or π * antibonding [29][30][31][32] orbital of the partner molecule. This same idea extends beyond chalcogen atoms, to other electronegative atoms, notably members of the halogen [33][34][35][36][37][38] and pnicogen [39][40][41][42][43][44] families, and there are very recent works that suggest that even the less electronegative C group of the periodic table can engage in very similar bonding interactions, known as "tetrel bonds." 45,46 The present work investigates the nature of O· · ·O interactions within the context of the ozone dimer.…”

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

“…Let us notice that recent works have shown that halogen bonds can occur inside carbon nanotubes and in DNA base pairs . Halogen bonding can characterize rational drug design and has also been identified in halogenated ether derivatives used as anesthetics …”

Theoretical studies of the interaction between enflurane and water

“…This can be related to a larger basicity (PA = 165 kcal mol −1 ) and a lower acidity (DPE = 390 kcal mol −1 ) of water molecule, in comparison to the corresponding values calculated for the two conformers of enflurane. Let us also mention that the complex between CH 3 OCHCl 2 …H 2 O (PA(O) = 174 kcal mol −1 ) is stabilized by an O w H w …O interaction, while in the CHFClOCHF 2 …H 2 O complex (PA(O) = 155 kcal mol −1 ), the CH…O w distance is shorter than the O w H w …O, showing the predominance of the CH…O w hydrogen bond over the O w H w …O interaction [27]. In contrast, the complex between CH 2 FCHO (PA(O) = 161 kcal mol −1 , DPE(CH) = 352.3 kcal mol −1 ) and water shows a preference for a cyclic structure, the O w H w …O hydrogen bond being shorter than the CH…O w one [28].…”

“…Binding energies and DPEs vary in a very small range and no correlation could be found between these two parameters as in the case of the halogenated ethers and water complexes [27]. …”