Monomeric and dimeric metal complexes of a simply prepared and versatile pentapyridyldiamine

The new pentapyridyldiamine, BPA-TPA, is easily made and has been used to prepare [Cu2(BPA-TPA)Br2]2Br2[Cu2Br4] and [Fe(BPA-TPA)](ClO4)2. The crystal structures of these complexes reveal BPA-TPA to be a versatile ligand, for example, capable of bridging two metal centres in chiral [Cu2(μ2-BPA-TPA)Br2]22+ ‘wedges’ or wrapping about a larger metal ion to give novel homoleptic seven co-ordinate species such as the chiral [Fe(κ7N-BPA-TPA)]2+ ion.