By using electrospray ionization mass spectrometry (ESI-MS), it was proven experimentally that the univalent thallium cation (TV) forms with [2.2.2]paracyclophane (C24H24) the cationic complex species [Tl(C24H24)](+). Further, employing quantum mechanical DFT calculations, the most probable structure of the [Tl(C24H24)](+) complex was derived. In the resulting complex with a symmetry very close to C-3, the 'central' cation TV is bound by six bonding interactions to six carbon atoms from the three benzene rings of the parent [2.2.2]paracyclophane ligand via cation-pi interaction. (C) 2015 Elsevier B.V. All rights reserved.