title: Experimental evidence for blue-shifted hydrogen bonding in the fluoroform-hydrogen chloride complex: a matrix-isolation infrared and ab initio study.
abstract: The 1:1 hydrogen-bonded complex of fluoroform and hydrogen chloride was studied using matrix-isolation infrared spectroscopy and ab initio computations. Using B3LYP and MP2 levels of theory with 6-311++G(d,p) and aug-cc-pVDZ basis sets, the structures of the complexes and their energies were computed. For the 1:1 CHF3-HCl complexes, ab initio computations showed two minima, one cyclic and the other acyclic. The cyclic complex was found to have C-H · · · Cl and C-F · · · H interactions, where CHF3 and HCl sub-molecules act as proton donor and proton acceptor, respectively. The second minimum corresponded to an acyclic complex stabilized only by the C-F · · · H interaction, in which CHF3 is the proton acceptor. Experimentally, we could trap the 1:1 CHF3-HCl cyclic complex in an argon matrix, where a blue-shift in the C-H stretching mode of the CHF3 sub-molecule was observed. To understand the nature of the interactions, Atoms in Molecules and Natural Bond Orbital analyses were carried out to unravel the reasons for blue-shifting of the C-H stretching frequency in these complexes.
authors: Chemistry Group, Indira Gandhi Centre for Atomic Research , Kalpakkam 603 102, Tamil Nadu, India.
authors: R
authors: R
authors: Gopi
authors: N
authors: N
authors: Ramanathan
authors: K
authors: K
authors: Sundararajan
mesh_terms: D005617:Chlorofluorocarbons, Methane / Q000737:chemistry*; D006851:Hydrochloric Acid / Q000737:chemistry*; D006860:Hydrogen Bonding; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared
chemical_list: D005617:Chlorofluorocarbons, Methane; D006851:Hydrochloric Acid; C009554:fluoroform