Two zinc() coordination polymers based on flexible co-ligands featuring assembly imparted sensing abilities for CrO and -NP

Two new Zn( ii ) coordination complexes, formulated as [Zn(opda)(pbib)] ( 1 ) and [Zn(ppda)(pbib)(H 2 O)] ( 2 ), (H 2 opda = 1,2-phenylenediacetic acid, H 2 ppda = 1,4-phenylene-diacetic acid, pbib = 1,4-bis(1-imidazoly)benzene), have been synthesized. The opda ligands extend a 1D chain containing (Zn-pbib) polymer chains into a 2D layer in 1 . In 2 , the ppda ligands link Zn( ii ) atoms to form a 2D network, then the rigid bis(imidazole) ligands give rise to the 3D structure. The fluorescence property application and mechanisms of two complexes for detecting Cr 2 O 7 2− and o -NP have been researched. For two complexes, the high quenching percentage in low concentration aqueous solution are 95.75% (Cr 2 O 7 2− , 1 ), 95.28% (Cr 2 O 7 2− , 2 ) and 97.56% ( o -NP, 1 ), 96.59% ( o -NP, 2 ). Compared with 2 , complex 1 has higher quenching percentage, this could be because 1 is a 3D supramolecular with a large hole. The detection limits have been measured to be 2.992 × 10 −7 M (Cr 2 O 7 2− , 1 ), and 4.372 × 10 −7 M (Cr 2 O 7 2− , 2 ), 2.103 × 10 −7 M ( o -NP, 1 ), 1.862 × 10 −7 M ( o -NP, 2 ), respectively. The emissions of two complexes could be effectively and selectively quenched by o -NP and Cr 2 O 7 2− , showing their potential as multi-responsive luminescent sensors. Two zinc( ii ) complexes exhibit the different architectures, and they have been shown to be excellent discriminative probe for the highly selective and sensitive detection of Cr 2 O 7 2− and o -NP based on their sensitive fluorescence quenching.