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

Hydrothermal reaction of a d10 configuration divalent metal precursor with flexible-arm aromatic ortho-dicarboxylates and a bis(pyridyl)piperazine-type neutral co-ligand has generated four coordination polymers, some with rare topologies. {[Cd(hmph)(4-bpmp)1.5]·4H2O}n (1, hmph = homophthalate, 4-bpmp = bis(4-pyridylmethyl)piperazine) manifests a new 3-fold interpenetrated uninodal 5-connected 3-D net with a very simple 4466 topology, different from the usual sqp 5-connected topology. [Cd2(hmph)2(4-bpfp)]n (2, 4-bpfp = bis(4-pyridylformyl)piperazine) displays a rare 4,5-connected binodal tcs net with (4462)(4466) topology. [Zn2(1,2-phda)2(4-bpmp)(H2O)2]n (3, 1,2-phda = 1,2-phenylenediacetate) possesses an uncommon 3,4-connected binodal 2-D layer with (426)(42638) (V2O5 prototype) topology. [Zn2(hmph)2(4-bpfp)]n (4) has a decorated (4,4) grid topology with embedded [Zn2(OCO)4] paddlewheel clusters. All materials exhibit ligand-centered fluorescent behavior. Thermal degradation behavior of the 3-D network materials is reported.