Syntheses, structures and fluorescent properties of cadmium coordination polymers based on 2,3′,5,5′-biphenyl tetracarboxylate and N-donor ancillary ligands

Self-assembly of cadmium(II) salt based on 2,3′,5,5′-biphenyl tetracarboxylate with or without various N-donor ligands affords a series of coordination polymers, namely {[Cd1.5(Hbptc)(H2O)4.5]·2H2O}n (1), {[Cd2(bptc)(2,2′-bipy)2]·2H2O}n (2), {[Cd2(bptc)(pyp)2(H2O)2]}n (3), [Cd(H3bptc)2(bip)2]n (4), and {[Cd2(bptc)(bpt)(H2O)]·H2O}n (5), where H4bptc = 2,3′,5,5′-biphenyl tetracarboxylic acid, 2,2′-bipy = 2,2′-bipyridine, pyp = 3-(pyrid-2-yl)pyrazole, bip = 3,5-bis(1-imidazol)pyridine, bpt = 3,5-bis(4-pyridyl)-1,2,4-triazolyl. Their structures were determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis and IR spectra. Complex 1 shows a 2D helical layer, which is further extended to a 3D supermolecule network through inter-layer C–H⋯O hydrogen bonds and π⋯π stacking interactions. Complex 2 exhibits a (3,6)-connected (43)2(46.66.83)-kgd topology. Complex 3 possesses a 2D (3,5)-connected (4.5.6)(4.53.64.72) net based on 1D tube-like chains. Complex 4 has a 1D polymeric ribbon containing left- and right-handed helical chains, which are further hydrogen bonded to form a 2D supermolecule layer. Complex 5 possesses a 3D (4,5,7)-connected framework. Moreover, the fluorescent properties of 1–5 in the solid state have been investigated.

Five Cd(II) coordination polymers with 2,3′,5,5′-biphenyl tetracarboxylate or mixed 2,3′,5,5′-biphenyl tetracarboxylate and N-donor ligands have been synthesized and structurally characterized. Moreover, fluorescent properties of these complexes have also been investigated.Figure optionsDownload as PowerPoint slide