The electronic structure and spectroscopic properties of [Hg-3(o-C6F4)(3)](n) center dot {benzene} (n = 1, 2) were studied at the HF, MP2 and PBE levels. The interaction between [Hg-3(o-C6F4)(3)](n) and benzene at the HF and MP2 levels was analyzed. Secondary pi-interactions (Hg-benzene) were found to be the main contribution short-range stability in the [Hg-3(o-C6F4)(3)] center dot {benzene} complex. At the MP2 and PBE levels equilibrium Hg-C distances of 338.4 and 361.4 pm; and interaction energies of 46.6 and 29.2kJ/mol were found, respectively. The absorption spectra of these complexes were calculated by the single excitation time-dependent method at PBE level. (C) 2008 Elsevier B.V. All rights reserved.