Zinc and cadmium flexible-arm ortho-dicarboxylate bis(pyridyl)piperazine coordination polymers with rare two- and three-dimensional topologies

► Cadmium and zinc flexible arm ortho-dicarboxylate coordination polymers. ► Bis(pyridyl)piperazine-type neutral ancillary ligands. ► New 3-fold interpenetrated uninodal 5-connected 3-D net. ► Rare 4,5-connected binodal tcs net with (4462)(4466) topology. ► Uncommon 3,4-connected binodal layer with V2O5 topology.