Anion-Controlled Assembly of a Silver-Responsive Bifunctional Coordination Polymer with Detection and Large Adsorption Capacity.

The recognition and adsorption of silver ions (Ag + ) from industrial wastewater are necessary but still challenging. Herein, we constructed four Zn(II)-based coordination polymers (CPs), namely, [Zn(btap) 2 (NO 3 ) 2 ] n ( 1 ), [Zn(btap)(SO 4 )(H 2 O) 3 ] n ( 2 ), {[Zn(btap) 2 (H 2 O) 2 ]·(ClO 4 ) 2 } n ( 3 ), and [Zn(btap)Cl 2 ] n ( 4 ), by using 3,5-bis(triazol-1-yl)pyridine (btap) with different anionic Zn(II) salts. The crystal structures of 1 - 4 , varying from one-dimensional beaded ( 1 ) and zigzag chain ( 2 ) to two-dimensional sql ( 3 ) and bex ( 4 ) typologies, were regulated by the coordination modes of btap and the counter-anions. The water stability, pH stability, thermostability, and luminescent properties of the CPs were investigated. The luminescence performances in a series of cations and anions were also explored. Considering the high density of chloride groups in the structure, 4 showed luminescence sensing for Ag + [ K SV = 9188.45 M - 1 and a limit of detection (LOD) of 4.9 μM], as well as an excellent ability for Ag + adsorption in aqueous solution (maximum adsorption capacity, 653.3 mg/g). Additionally, anti-interference experiments revealed that 4 had excellent recognition and adsorption capacities for Ag + even when multiple ions coexisted. Moreover, XRD, EDS, and XPS analyses confirmed that the coordination of Ag + with chloride groups in 4 resulted in excellent adsorption capacity and prevented ligand-to-ligand electron transfer, showing excellent detection ability. Suitable coordination sites were introduced to interact strongly with Ag + , along with detection and large adsorption capacity. Our strategy can effectively design and develop multifunctional CP-based materials, which are applicable in removal processes and environmental protection, by regulating anions in the self-assembly and introducing CP functional groups.