Density functional theory calculations were performed on 16 cation-pi complexes formed by cations of Li+, Na-divided by, Be2+, and Mg2+ and pi systems of benzene, 1,3,5-trifluorobenzene (TFBZ), 1,3,5-trimethylbenzene and 1,3,5-trimethoxybenzene (TMOBZ). The calculations using the GIAO-based method revealed that cation-pi interaction has remarkable effect on NMR chemical shifts. It was also found that, for all substituted aromatics. the cation-pi interaction between the cations and the aromatic carbon atoms without substituent attached is stronger than that with substituent, and that TMOBZ with electron-giving substituent is the best cation-pi acceptor, while TFBZ with electron-withdrawing substituent is the worst. (c) 2006 Elsevier B.V. All rights reserved.