Synthesis and characterization of 1D and 2D cadmium(II)-2,2'-bipyridine-N,N'-dioxide coordination polymers bridged by pseudohalides

Three cadmium(II) coordination polymesrs (CP) based on 2,2′-bipyridine-N,N′-dioxide (bipy-O2) as a coligand bridged by azido, thiocyanato and dicyanamido anions were synthesized. The complexes catena-[Cd(bipy-O2)(μ1,1-N3)2] (1), catena-[Cd(bipy-O2)(μ1,3-NCS)2] (2) and catena-[Cd(bipy-O2)(μ1,5-dca)2] (3), where dca = dicyanamide anion, NCNCN− were structurally characterized by X-ray single crystallography. The complexes display six-coordinated geometry around the central Cd(II) ion through the two oxygen atoms of the seven-membered chelating bipy-O2 molecule in cis conformation and four N-donor atoms of the doubly bridged end-on N3− in complex 1 and in the dicyanamido complex 3 as well as the doubly bridged end-to-end through the terminal two Nsingle bond and two S-donors in the corresponding thiocyanato compound 2. These arrangements led to the generation of 1D CP in the azido and thiocyanato complexes and a 2D CP in the dicyanamido complex 3. The luminescence and thermoanalytical properties of the complexes were also investigated.