Zn(ii) and Cd(ii) coordination polymers with a new angular bis-pyridyl-bis-amide: synthesis, structures and sensing properties

Abstract

Zn(II) and Cd(II) coordination polymers constructed from a new angular bis-pyridyl-bis-amide ligand and naphthalene-1,4-dicarboxylic acid (1,4-H₂NDC), {[Zn₂(L)(1,4-NDC)₂]·2H₂O} [L = 4,4′-oxybis(N-(pyridin-3-ylmethyl)benzamide)], 1, and {[Cd₂(L)(1,4-NDC)₂]·EtOH}, 2, have been solvothermally synthesized and structurally characterized by using single-crystal X-ray diffraction. While complex 1 displays a 2D double layer with the rare (4⁶·6⁴)-5 L4 topology, complex 2 shows a 3D framework with a new (4·5·6)(4⁵·5⁵·6⁹·7·8) topology. Both complexes 1 and 2 display luminescence properties and 2 exhibits a high sensitivity toward the detection of Fe³⁺ ions with a K_sv value of 1.9 × 10⁴ M⁻¹. The quenching effect can most probably be ascribed to the interactions between the metal ions and the amide carbonyl oxygen atoms.