Two isostructural cobalt(II) coordination polymers with both polyrotaxane and polycatenane features assembled with a V-shaped rigid ligand

Two novel cobalt(II) coordination polymers (CPs), [Co(BPFP)2(sca)]n (1), [Co(BPFP)2(sda)]n (2), [BPFP = 2,8-di(pyridin-4-yl)dibenzo[b,d]furan, H2sca = succinic acid, H2sda = thiophene-2,5-dicarboxylic acid], have been synthesized hydrothermally based on a V-shaped rigid ligand BPFP. Their structures were fully characterized by elemental analysis, FT-IR spectroscopy and X-ray single-crystal diffraction methods. Compound 1 is a 2-fold parallel interpenetrating network consist of two identical sets of 2D layer motifs and shows both polyrotaxane and polycatenane characters. Compound 2 has the same structural feature as compound 1, except that the sca2− anions are replaced by the sda2− anions. The Powder X-ray diffraction (PXRD) analyses and thermogravimetric analyses were carried out to confirm the phase purity and the thermal stabilities of the compounds 1 and 2. In addition, the solid-state UV-vis absorption spectra were also investigated.