Coordination assemblies of CdII with 2,2′:6′,2-terpyridine (terpy), 2,3,5,6-tetra-(2-pyridyl)pyrazine (tppz) and pseudohalide ions - structural diversification and luminescence properties

Nine new terpy-or tppz-containing cadmium(II) coordination compounds,[Cd(mu(1,5)-dca)(NO3)(terpy)](n) (1),[Cd(mu(1,5)-dca)(terpy)(H2O)](n)center dot n(dca) (2), [Cd(mu(1,3)-N-3)(NO3)(terpy)](n) (3), [Cd(N-3)(NO3)(terpy)(H2O)] (4), [Cd-2(mu(1,1)-N-3)(2)(N-3)(2)(terpy)(2)] (5), [Cd(mu(1,5)-dca)(NO3)(tppz)](n) (6), [Cd(dca)(NO3)(tppz)(H2O)] (7), [Cd-2(mu(1,1)-N-3)(2)(NO3) (2)(mu-tppz)](n)center dot 2nMeOH (8) and [Cd-2(mu(1,1)-N-3)(mu(1,3)-N-3)(m-tppz)](n) (9), have been successfully synthesized in the reaction of Cd(NO3)(2) with multidentate N-heterocyclic ligands and inorganic ions (N-3(-) and N(NC)(2)(-) abbreviated as dca(-)). The resulting compounds were structurally characterized by single crystal X-ray diffraction analysis and further characterized by infrared spectra (IR), elemental analyses, powder X-ray diffraction (XRPD), and thermogravimetric analyses (TGA). The X-ray studies demonstrated a cooperative impact of the polypyridyl ligand and the auxiliary inorganic ion on the final molecular architectures of cadmium(II) coordination compounds. Different topologies, ranging from mononuclear molecular to two-dimensional coordination networks, were confirmed for 1-9. The photoluminescence behaviour of 1-9 was also discussed. All of these coordination compounds are luminescent in the solid state, with the emission maxima varying in the visible light region within the range of 460-600 nm. The difference in emission behaviour for 1-9 is attributed to the coordination environments of the metal ions and the rigidity of solid-state crystal packing.