The role of weak interactions in self-assembly of supramolecular associations of benzothiazole derivatives and their coordination compounds

New benzothiazole derivatives and their transition metal coordination compounds were synthesized and structurally characterized. The participation of weak interactions, as H-bonding, pi-stacking, O -> S, N -> S and S lone pair center dot center dot center dot pi, on the stabilization of their supramolecular assemble was analyzed. The bis-benzothiazole (ebbtz) derivative was obtained from the reaction of benzothiazole-2-carboxaldehyde and ethylenediamine. When reacting this ligand with copper (II) chloride, an electrophilic addition of methanol, as a methoxy group, gave place to the amino ether derivative on the coordination compound [Cu(MeO-ebbtz)Cl]Cl center dot 4H(2)O. The supramolecular arrangement of this compound is stabilized by H-bonding, O -> S, N -> S, lp(S)center dot center dot center dot pi and pi-stacking interactions. Whereas, from the reaction in situ of benzothiazole-2-carboxaldehyde, ethylenediamine and copper (II) bromide, the polymeric [Cu-2(mu-Br)(3)(ebtz)Br](n) compound was obtained. In this compound, the copper (II) atoms present two different geometries, tetrahedral and octahedral, where a 3D assembly is driven by lp(S)center dot center dot center dot pi and pi center dot center dot center dot pi stacking. Two isostructural [M(H2O)(2)(CH3OH)(4)]center dot 2(prbtz) (M = Co-II and Ni-II) compounds and a polymeric sodium complex were obtained with 3-(benzothiazol-2-ylthio)-1-propanesulfonate (prbtz). In the [Na-2(prbtz)(2)(H2O)(2 mu)-(H2O)](n) polymer, the prbtz(-) is bound to the metal ion in a bent conformation, presenting a supramolecular arrangement stabilized by H-bonding, N -> S, T-shape and lp(S)center dot center dot center dot pi interactions. On the other hand, in the [M(H2O)(2)(CH3OH)(4)]center dot 2(prbtz) compounds, prbtz(-) co-crystallized, presenting an extended conformation, mainly with lp(S)center dot center dot center dot pi interactions. Additionally, theoretical calculations on the association between two ebbtz molecules, were performed. The results indicate that these molecules have a binding energy of 79.49 kJ/mol promoted by lp(S)center dot center dot center dot pi and pi center dot center dot center dot pi stacking interactions, taking place at the frontier LUMO and HOMO molecular orbitals. (C) 2017 Elsevier B.V. All rights reserved.