Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (12): 2817-2823.doi: 10.3866/PKU.WHXB201208291


Properties and Weak Directionality of the π-Lithium Bond in C2H4-nFn···LiH (n =0, 1, 2) Dimers

WANG Shu-Jian, LI Ying, WU Di   

  1. State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, P. R. China
  • Received:2012-07-05 Revised:2012-08-27 Published:2012-11-14
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21173095).


Using the second-order Møller-Plesset perturbation method, the structures and π-lithium bonding properties of C2H4-nFn···LiH (n=0, 1, 2) dimers were analyzed. The results showed that F substitution led to π electron cloud deformation in the ethylene molecule, and subsequent changes (deviation, elongation, and bend) in the π-lithium bonds in C2H4-nFn···LiH. In contrast to the π-hydrogen bonds in the C2H4-nFn···LiH (n=0, 1, 2) systems, the π-lithium bonds in the C2H4-nFn···LiH dimers were obviously bent because of secondary hydrogen bond interactions, and they exhibited weak directivity. For the four C2H4-nFn···LiH dimers, the strength of the interaction was 33.85 kJ·mol-1 (C2H4-LiH)>27.32 kJ·mol-1 (C2H3F-LiH)>21.34 kJ·mol-1 (cis-C2H2F2-LiH)>20.25 kJ·mol-1 (g-C2H2F2-LiH) at the CCSD(T)/6-311++G(3df, 3pd) level. This indicates that the F substituent effect decreases the strength of the interaction between ethylene and LiH molecules.

Key words: π-Lithium bond, π-Hydrogen bond, Weak interaction, Second-order Mø, ller-Plesset perturbation theory, Substituent effect