A New Ligand for the Formation of Triangular Building Blocks in Supramolecular Chemistry

Abstract

AbstractIn this article we describe the synthesis, characterisation and metal binding properties of tris(5‐bromo‐2‐hydroxybenzylidene)triaminoguanidinium chloride [H6Br3L]Cl (1), which can be seen as a triangular building block for supramolecular chemistry. 1 crystallises either in a triclinic (1a) or a rhombohedral (1b) system depending on the used solvent . The pure ligand adopts a conformation unfavourable for the coordination of metal centres, but in the presence of a base or a basic metal salt, a change in the conformation can be observed. The reaction of 1 with (NH4)6[Mo7O24] in the absence of further base results in the formation of small, red crystal needles with the formula [Mo(O)2(OH2)(H3Br3L)]·2 DMF (2), while the reaction of 1 with CuCl2, sodium 5,5‐diethylbarbiturate (NaHbar) and Et3N leads to the formation of dark red‐black crystals with the formula (Et4N)2[{Cu(Hbar)}3Br3L] (3). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)