A pi-stacked phenylacetylene and 1,3,5-triazine heterodimer: a combined spectroscopic and ab initio investigation

Abstract

The IR-UV double resonance spectroscopy of a complex between phenylacetylene and 1,3,5-triazine reveals that the acetylene C-H group of phenylacetylene is minimally perturbed due to its interaction with 1,3,5-triazine. Further, the IR spectrum clearly indicates that 1,3,5-triazine primarily interacts with pi-electron density of the benzene ring in phenylacetylene. Geometries obtained at the DFT/MO6-2X and MP2/aug-cc-pVDZ levels, combined with highly accurate energy calculations at the complete basis set (CBS) limit of CCSD(T), establish formation of the displaced pi-stacked heterodimer between phenylacetylene and 1,3,5-triazine.