New Zn(II) coordination polymer based on 5-nitroisophthalate and 2,5-di-4-pyridinylphenol: Synthesis and photoluminescent sensing of ATP

The abnormal concentration of adenosine triphosphate (ATP) can seriously affect the human health. Therefore, a sensitive and rapid assay of ATP is of vital importance. In this work, a new 2D Zn(II)-based coordination polymer (CP) with composition [Zn(NPA)(DPP)& sdot;0.5DMF]n (1) has been synthesized using nitro-functionalized 5-nitroisophthalic acid (NPA) ligand and 2,5-di-4-pyridinylphenol (DPP) co-ligand and characterized. The single crystal X-ray diffraction study reveals that in 1 the Zn(II) center adopts four coordinated distorted tetrahedral geometry and bonded to two carboxyl oxygen of two NPA2- ligands and the two pyridyl nitrogen of two DPP coligands. The application of CP 1 as photoluminescent sensor for the detection of biomolecules has been assessed. The CP 1 displays highly sensitive and selective detection of ATP displaying the limit of detection (LOD) 1.0288 mu M and Stern-Volmer constant (KSV) of 1.36 x 10-4 M- 1. The selective sensing ability of CP 1 towards ATP has been elucidated through theoretical calculations, which indicate that among all examined biomolecules, only ATP possesses a LUMO energy level lower than that of CP 1 and hence facile excited energy transfer from 1 to ATP can lead to luminescence quenching. Furthermore, a CP 1-loaded paper-based micro-sensor has been developed for real-time and highly sensitive ATP detection.