Phenylacetylene–water complex: Is it n⋯σ or H⋯π in the matrix?

Does a hydrogen bonded complex with dual contacts show synergism? A matrix isolation infrared and ab-initio study of propargyl alcohol–water complex

“…It is worth mentioning that the global minimum computed for the PA-H 2 O system was structurally similar to the global minimum computed for the phenylacetylene-H 2 O system [20]. In the PA-H 2 O complex, we see a strong OeH$$$O interaction together with a relatively weaker OeH$$$p.…”

“…In other words, both complexes show X-H$$$O (X ≡ C or O) together with an OeH $$$ p interaction. However, while in the PA-H 2 O system, this global minimum was observed and the only one observed in the matrix, the computed global minimum was not observed in the matrix isolation experiments of phenylacetylene-H 2 O [20]. Rather in that experiment, an n-s complex, which was a local minimum involving the interaction between the acetylenic hydrogen of phenylacetylene and the oxygen of H 2 O was observed.…”

“…Matrix isolation experiments were performed using a Sumitomo closed cycle helium compressor-cooled cryostat (HC-4E1) to attain a temperature of 12 K. The experimental details have been described elsewhere [17][18][19][20][21].…”

Intermolecular Complexes and Molecular Conformations Directed by Hydrogen Bonds: Matrix Isolation and Ab Initio Studies

“…Details as to how the scaling factors were computed are discussed in detail in many of our earlier publications. [18][19][20][21] The computed wavenumbers together with the intensities of the various vibrational modes were used to simulate a vibrational spectrum using the SYNSPEC program, 22 assuming a Lorentzian line profile with a full-width-half-maximum (FWHM) of 1.0 cm −1 .…”

“…Phenylacetylene, Propargyl Alcohol and Propargyl Amine systems The first system that we will consider is the phenylacetylene-water system (PhAc-H 2 O). 18 This system presents three isomeric structures for the hydrogen-bonded systems, as shown in Fig. 1.…”