Theoretical study on the π hydrogen-bonded complex between HArF and ethylene

An ab initio computational study of the properties of π hydrogen-bonded complex of HArF and C2H4 has been carried out at the MP2/6-311++G(2d,2p) level of theory. For comparison, the C2H4···HF complex was also studied. The T-shape complex of C2H4···HArF was found to have a larger red shift of the H-Ar stretching frequency, accompanied by a decrease in the infrared intensity of the stretching mode and larger elongation of the H-Ar bond. The insertion of an Ar atom into the HF molecule causes an increase of about 47% in the interaction energy at the QCISD theory. The charge transfer within the HAF molecule upon complexation was examined with the natural bond orbital analyses. The minima on the basis set superposition errors (BSSE)-counterpoise-corrected potential-energy surface (PES) have been determined and the results were compared with those obtained from the uncorrected PES.