Zinc(ii)-based coordination polymer encapsulated Tb3+ as a multi-responsive luminescent sensor for Ru3+, Fe3+, CrO42-, Cr2O72- and MnO4-

A zinc(ii)-based coordination polymer (CP), namely [Zn(modbc)(2)](n) (Zn-CP) (modbc = 2-methyl-6-oxygen-1,6-dihydro-3,4 '-bipyridine-5-carbonitrile), has been synthesized and characterized. Single-crystal structural determination reveals that Zn-CP is a two-dimensional framework structure with tetranuclear homometallic Zn-4(modbc)(4) units cross-linked by modbc. The excellent luminescence as well as good stability of Zn-CP do not enable it to have selective sensing capability for different ions. After encapsulation of Tb3+ in Zn-CP, the as-obtained fluorescent functionalized Tb3+@Zn-CP maintained excellent luminescence as well as stability, which made it a highly selective and sensitive multiresponsive luminescent sensor for Ru3+, Fe3+, CrO42-, Cr2O72-, and MnO4- with high sensitivity, good anti-interference performance, and quick response time (similar to 10 s). The detection limits are 0.27 mu M, 0.57 mu M, 0.10 mu M, 0.43 mu M and 0.15 mu M, respectively. A possible sensing mechanism was discussed in detail.