Synthesis, luminescence, and structural characterization of Zn and Cd coordination polymers of flexible bis(imidazolyl) derivatives

Coordination polymers [Zn(imc)(L1)] · H2O, (1, imc = iminodiacetate, L1 = bis(N-imidazolyl)methane) [Zn(hba)2(L2)]2 · EtOH · 3H2O, (2, hba = p-hydroxybenzoate, L2 = bis(N-benzimidazolyl)methane), [Cd(mal)(H2O)(L3)](3, L3 = 1,4-bis(N-imidazolyl)butane, mal = maleate) have been prepared and structurally characterized. Complex 1 consists of hexa-coordinated central Zn ions and exhibits 2D network structure. The Zn atoms in 2 have tetrahedral coordination geometry, and are linked by bis(imidazolyl) ligands into 1D chain structure. The cadmium ions in 3 are hepta-coordinated with pentagonal bipyramidal geometry. Complex 3 displays 2D grid structure. The TGA showed that the coordination polymers are stable up to 200 °C. All the three complexes are emissive at room temperature in their solid state.