title: Spectroscopic and Ab Initio Investigation of C-H⋅⋅⋅N Hydrogen-Bonded Complexes of Fluorophenylacetylenes: Frequency Shifts and Correlations.
abstract: The C-H⋅⋅⋅N hydrogen-bonded complexes of several fluorophenyacetylenes with ammonia and methylamine were characterized by a redshift in the acetylenic C-H stretching vibration of the phenylacetylene moiety. These redshifts were linearly correlated with the stabilization energies calculated at the CCSD(T)/CBS//MP2-aug-cc-pVDZ level. Analysis of various components of the interaction energy indicated that the observed redshifts were weakly correlated with the electrostatic component. The weaker linear correlation between the frequency shifts and the electrostatic component between two data sets can perhaps be attributed to the marginal differences in the Stark tuning rate and zero-field shifts. The induction and exchange-repulsion components were linearly correlated. However, the dispersion component depends on the nature of the hydrogen-bond acceptor and shows a quantum jump when the hydrogen-bond acceptor is changed from ammonia to methylamine. The observed linear correlation between the redshifts in the C-H stretching frequencies and the total stabilization energies is due to mutual cancellation of deviations from linearity between various components.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai -, 400076, India.
authors.forename: Arghya
authors.initials: A
authors.lastname: Dey
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai -, 400076, India.
authors.forename: Sohidul Islam
authors.initials: SI
authors.lastname: Mondal
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai -, 400076, India.
authors.forename: Saumik
authors.initials: S
authors.lastname: Sen
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai -, 400076, India. naresh@chem.iitb.ac.in.
authors.forename: G Naresh
authors.initials: GN
authors.lastname: Patwari
keywords: Stark tuning rates; density functional calculations; donor-acceptor systems; hydrogen bonds; vibrational spectroscopy