A Theoretical Study of Intermolecular Interaction and Hydrogen Bond for Furan with HCl and CH<SUB>4- n </SUB>Cl<SUB> n </SUB> ( n = 0-3)

Internet Electronic Journal of Molecular Design 01/2003;
Source: DOAJ


Furan has both the oxygen lone pair electrons and an aromatic π-electron. The study of the interaction between furan as a proton acceptor and a proton donor is important to understand the properties of furan and the related hydrogen bond. The geometries, intermolecular energies and vibrational properties of the furan-HCl and furan-CH4- n Cl n ( n = 0-3) complexes have been performed using the second order Moller-Plesset perturbation theory. The NBO analysis of the optimized geometries has also been performed. The optimized geometries of furan-HCl and furan-CH4- n Cl n ( n = 0-3) show both the C(Cl)-H...O and C(Cl)-H...π interactions. In all of the optimized geometries of furan-CH4- n Cl n ( n = 0-3), C-H bond lengths are shorten and vibrational frequencies are blue-shifted, while for the furan-HCl complex, C-H bond length is lengthened and vibrational frequencies are red-shifted. The NBO analysis shows that, for the furan-CH4- n Cl n ( n = 0-3) complexes, the charge transfer from the lone pairs of the O atom to both σ*(CH) antibonding MO and lone pairs of Cl atom, which is the important feature for blue-shifted hydrogen bond. Both lone pairs and π electrons of furan can be acted as a proton acceptor interacting with a proton donor. Cl-H...O(π) is a conventional hydrogen bond , while C-H...O(π) is a blue-shifted hydrogen bond.

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