title: Binary complexes of tertiary amines with phenylacetylene. Dispersion wins over electrostatics.
abstract: The structures of the binary complexes between phenylacetylene and several tertiary amines viz., triethylamine, 1-ethylpiperidine, 1-ethylpiperazine, 1-azabicyclo[2.2.2]octane, and 1,4-diazabicyclo[2.2.2]octane were inferred using infrared-optical double resonance spectroscopy. The IR spectra in the acetylenic C-H stretching region clearly rule out the formation of electrostatic dominated C-HN hydrogen bonded complexes. The IR spectra also point to the fact that all the five tertiary amines interact with the extended pi electron density of the phenylacetylene moiety, leading to the formation of multidentate C-Hpi hydrogen bonded complexes. Additionally a very weak electrostatic C-HN hydrogen bond enhances the stability of the complex marginally. The multidentate C-Hpi hydrogen bonded complexes are stabilized by a substantial contribution from the dispersion energy.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India.
authors.forename: Surajit
authors.initials: S
authors.lastname: Maity
authors.forename: G Naresh
authors.initials: GN
authors.lastname: Patwari
authors.forename: S
authors.initials: S
authors.lastname: Karthikeyan
authors.forename: Kwang S
authors.initials: KS
authors.lastname: Kim
mesh_terms: D000114:Acetylene / Q000031:analogs & derivatives* / Q000737:chemistry; D000588:Amines / Q000737:chemistry*; D006860:Hydrogen Bonding; D013050:Spectrometry, Fluorescence; D013055:Spectrophotometry, Infrared; D055672:Static Electricity; D013816:Thermodynamics
chemical_list: D000588:Amines; C044736:phenylacetylene; D000114:Acetylene