With the aim of checking whether the O(phenoxo)2O(methoxy) 2 compartment of 3-methoxysalicylaldehyde-diamine ligands can interact with an aquated proton, the work in this investigation presents the syntheses, characterization, crystal structures and diffuse reflectance spectra of the products obtained from the reactions of three mononuclear copper(II) compounds derived from three H2LOMe ligands (H 2LOMe-en, H2LOMe-op and H 2LOMe-hex) with perchloric acid in DMF, MeOH and MeOH-MeCN, where 'en', 'op' and 'hex' in the superscripts of the ligand symbols indicate that the diamine functionality comes from ethylenediamine, o-phenylenediamine and trans-1,2-diaminocyclohexane, respectively. From these reactions, the following six compounds have been isolated: [{Cu IILOMe-en}(Me2NH2)](ClO 4) (1), [{CuIILOMe-op}(Me2NH 2)](ClO4) (2), [{CuIILOMe-hex} (Me2NH2)](ClO4) (3), [{CuIIL OMe-en}2(enH2)](ClO4)2 (4, where enH2 means diprotonated ethylenediamine), [{Cu IILOMe-op}2(opdaH2)](ClO 4)2·2H2O (5, where opdaH2 means diprotonated o-phenylenediamine) and [{CuIIL OMe-hex}(MeOH2)](ClO4) (6). The Me 2NH2+ moiety in 1-3, NH3+ sites in 4 and 5 and MeOH2+ moiety in 6 interact with the O4 compartment by forming bifurcated hydrogen bonds. Interestingly, compound 6 is an unprecedented type of host-guest system. The individual units in 1-6 are self-assembled by non-covalent interactions to generate one, two and three-dimensional self-assemblies. A spectroscopic correlation has been enlightened. © 2014 Elsevier Masson SAS. All rights reserved.