Supramolecular metal helicate structures with incomplete metal ion coordination

Two flexible `polytopic' ligands take part in self assembly reactions with Ni(ii) salts to produce helical structures, with `incomplete' metal ion coo rdination, and the occupancy of empty coordination pockets by a water molec ule and a putative fluoride ion. [Ni-3(pd2am-H)(3)(H2O)](NO3)(3). 2H(2)O 1 consists of a localized Ni-2(N-N)(3) dinuclear centre with three N-N single bond bridges, and a distant mono-nuclear Ni(ii) centre, within the same mo lecular ion, and [Ni-2(2pzoap)(3)F](BF4)(3).8.5H(2)O 2 has a dinuclear stuc ture with two well separated octahedral Ni(ii) sites. In both cases a singl e entity (H2O 1, F- 2) occupies a potential coordination pocket. Antiferrom agnetic coupling is observed between the adjacent Ni(ii) centres in 1, asso ciated with the N-N bridging interactions, but the distant metal centres in 2 are uncoupled.