Quantum chemical study of hydrogen-bonded CH2CO…HX and CH2CCH2…HX (X = Cl, F) complexes

An ab initio quantum chemical study, largely at the 6–311 + + G∗ ∗/MP2 = full level of theory has been carried out on the 1:1 and 2:1 complexes of HX (X = Cl, F) with ketene and are compared with the corresponding isoelectronic complexes of H2CCCH2 and HX. Three possible modes of the hydrogen bond between HX and ketene via the dipole-induced dipole (X-H…C, X-H…O) and the weak X-H…π interactions were considered. The binding energy has been calculated after giving careful consideration to basis set superposition effects and zero-point vibrational energy effects. The electron correlation correction to the binding energy has also been computed. Weak X-H…π hydrogen bonds are perhaps possible with nonpolar CC and CC pi-clouds.