Supramolecular structures via hydrogen bonds and π-stacking interactions in novel anthraquinonedisulfonates of zinc, nickel, cobalt, copper and manganese

By using 1,10-phenanthroline as a blocking ligand, six new disulfonate complexes were hydrothermaly obtained and their self-assembling interactions studied, namely: [Co-2(2,6-AQDS)(2)(Phen)(4)] (1) (2,6-AQDS = anthraquinone-2,6-disulfonate, Phen = 1,10-phenanthroline), a dimeric molecular complex that exhibits 2D structure via pi-pi aromatic slipped and T-shaped stacking interactions; a series of isostructural compounds with formula [M(1,5-AQDS)(Phen)(2)(H2O)] (M = Co, Ni, Cu, and Zn, compounds 2, 3, 5, 6, respectively), (1,5-AQDS = anthraquinone-1,5-disulfonate, and [Mn(2,6-AQDS)(Phen)(2)(H2O)]center dot H2O (4). The metals cations are in octahedral coordination in all of them. These molecular complexes are arranged into 3D supramolecular structure by combination of pi-pi aromatic slipped and T-shaped stacking interactions, as well as O-H center dot center dot center dot O hydrogen bonds and C-H center dot center dot center dot O interactions. Studies on the catalytic activity of the obtained compounds for the oxidation of the methyl phenyl sulphide showed that [Ni(1,5-AQDS)(Phen)(2)(H2O)], 3, and [Co(1,5-AQDS)(Phen)(2)(H2O)], 2, act as heterogenous catalysts, being the nickel compound the most active and selective for this reaction. (C) 2011 Elsevier B. V. All rights reserved.