A new approach on diminutive effects for non-covalent interactions: fused bicyclic hydrogen-bonded complexes of hypohalous acids with fluoromethanol

ABSTRACTThe computational study of dimer and trimer complexes of fluoromethanol (CH2FOH) with one or two molecules of hypohalous acids (HOX; X = F, Cl or Br) was carried out at the MP2/aug-cc-pVDZ computational level. Also to show the reliability of these results, the binding distance and interaction energy have been compared with large basis set aug-cc-pVTZ level for some systems. The 1:1 ratio gives two different hexagonal and heptagonal ring complexes and the 1:2 ratio of CH2FOH/HOX leads to fused bicyclic hydrogen-bonded trimer adducts constructed from hexagonal and heptagonal rings. The results show diminutive effects in the range of 0.36–0.78 kcal/mol for the trimer bicyclic systems. Redshifts with bond elongations were observed for H–O and C–F bonds, while blueshifts along with bond contractions were seen for the C–H and the X–O bonds. The CH2FOH/HOX complexes were analysed using the Quantum Theory of Atoms in Molecules (QTAIM) and natural bond orbital methodologies.