Two Cd(II)/Mn(II) coordination polymers showing dual responsive fluorescence sensing for Fe3+ and o-NAL

Two new coordination polymers [Cd₂(pbib)_3.5(NO₃)₃]·NO₃ (1) and [Mn(pbib)₂(SO₄)] (2) (pbib = 1,4-bis(1-imidazoly)benzene) have been synthesized under hydrothermal conditions. Single-crystal X-ray diffraction analysis revealed that two complexes crystallize in the monoclinic system, space group C2/c and P2₁/c respectively. They have different 3D network structure. Furthermore, we have studied the performance and mechanism of fluorescence quenching detection of Fe³⁺ and o-NAL (o-NAL = o-Nitroaniline) with two coordination polymers. The diversities of the structures for two complexes have some effects on the fluorescence properties to accelerate the quenching rate of Fe³⁺ and o-NAL, especially complex 1. The high quenching percentage and the low detection limit of Fe³⁺ and o-NAL may make complexes 1–2 excellent candidates for multi-responsive fluorescent probe materials.