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: [Co2(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 π–π 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)]·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 π–π aromatic slipped and T-shaped stacking interactions, as well as O–H···O hydrogen bonds and C–H···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.