Carboxylate-induced Various Structures of Ni(II) Complexes with Fluorescence Sensing and Bifunctional Electrochemical Properties

We synthesized three new Ni(II) coordination polymers [Ni(L)(HIP)(H 2 O) 2 ]H 2 O(CP 1 ), [Ni(L)(NIP)]·2H 2 O(CP 2 ) and [Ni(L)(NDC)(H 2 O) 2 ](CP 3 )[L= N , N' -bis(pyridine-3-yl)thiophene-2,5-dicarboxamide, H 2 HIP=5-hydroxyisophthalic acid, H 2 NIP=5-nitroisophthalic acid, H 2 NDC=2,6-naphthalenedicarboxylic acid] by hydrothermal method, which were characterized by means of infrared spectra(IR), TG analyses, PXRD and single-crystal X-ray diffraction. The CP 1 is a 1D tubular structure based on [Ni-HIP] 2 loops and pairs of L ligands. CP 2 is a 2D 3,5-connected architecture, which consists of Ni-L linear chains and (Ni-NIP) 2 double chains. CP 3 is a 2D network, which features 4-connected topology. Solid-state luminescent behaviours of CP 1 —CP 3 were investigated. The CP 1 can detect Fe 3+ ions through luminescence quenching. The electrochemical properties of CP 1 buk-modified carbon paste electrode(CP 1 -CPE) has also been investigated, which has bifunctional electrocatalytic activity for oxidation of ascorbic acid and reduction of NO 2 − .