화학공학소재연구정보센터
Journal of Physical Chemistry A, Vol.118, No.29, 5529-5539, 2014
Experimental Evidence for Blue-Shifted Hydrogen Bonding in the Fluoroform-Hydrogen Chloride Complex: A Matrix-Isolation Infrared and ab Initio Study
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 center dot center dot center dot Cl and C-F center dot center dot center dot 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 center dot center dot center dot 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.