Diverse interpenetration schemes and topologies in cobalt coordination polymers constructed from 2-carboxycinnamic acid and a long-spanning dipyridylpiperazine ligand

Abstract

Hydrothermal reaction of cobalt nitrate, 2-carboxycinnamic acid (H2cca), and a long-spanning dipyridyl-type ligand resulted in three coordination polymers that were characterized by single crystal X-ray diffraction and manifested different structural topologies and interpenetration schemes. {[Co(cca)(4-bpmp)(H2O)2]·4H2O}n (1, 4-bpmp = bis(4-pyridylmethyl)piperazine) shows a 2-fold interpenetrated 4-connected 66dia network. Use of the dipyridylamide bis(4-pyridylformyl)piperazine (4-bpfp) produced a crystalline mixture of the major product 3D 6-connected 41263pcu network coordination polymer {[Co(cca)(4-bpfp)]·2H2O}n (2) and the minor product 1D chain coordination polymer [Co(dibf)2(4-bpfp)(H2O)2]n (3, dibf = 3-dihydro-3-oxo-1-isobenzofuranacetate). The in situ rearrangement of 2-carboxycinnamic acid in the presence of 4-bpfp produced the anionic lactone dibf in 3. Thermal decomposition behavior of the new major product phases was probed.