Ab initio calculations at the Hartree–Fock and correlated levels and density functional theory calculations have been performed with 6-31++G(d,p) and 6-311++G(d,p)basis sets on LiF and HF complexes of benzene, ethylene, and acetylene. Complex binding energies have been corrected for basis set superposition error, and zero point energy corrections have been done on Hartree–Fock binding energies. Computed results indicate that the complexes exist in different conformations and among them those with π-lithium and π-hydrogen bonds are the most stable. π-lithium bonds are stronger than π-hydrogen bonds. The computed binding energies and geometry of HF complexes correlate well with the available experimental results. LiF complexes with these π systems are found to be weaker than Li+ complexes but they are stronger than Li atom complexes. Natural bond orbital analysis traces the origin of the weak interactions that stabilize the complex. Li, as found in earlier cases, prefers the most symmetric site for interaction whereas proton prefers a nonsymmetric site in benzene complexes. Surprisingly, such a change of interaction geometry in LiF and HF complexes is found to change the donating π-orbitals in the benzene complexes.
Published in The Journal of Chemical Physics, Volume 109, 1998, pages 9820-9830.
Copyright 1998 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
The following article appeared in
Ammal, S. S. C. & Venuvanalingam, P. (1998). π-systems as lithium/hydrogen bond acceptors: Some theoretical observations. The Journal of Chemical Physics, 109, 9820. http://dx.doi.org/10.1063/1.477651
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