Copper(II) complexes of a tripyridyl ligand: Anion-dependent metallosupramolecular structures

A series of copper(ii) complexes of the ligand 2,6-bis(pyridin-3-ylethynyl) pyridine have been synthesised and characterised by 1H and DOSY NMR, IR and UV-Vis spectroscopies, mass spectrometry, elemental analysis and single crystal X-ray diffraction. In solution these systems display almost identical spectroscopic properties, however the solid state structures are shown to vary widely, depending upon the choice of anion. The tetrafluoroborate salt was revealed to be a discrete Cu2L4 cage-like helicate. The tosylate salt, whilst of the same Cu2L4 stoichiometry, was shown to be a coordination polymer. Finally the nitrate salt structure was observed to be a discrete Cu2L2 metallocycle.