Luminescent Zn(II) Coordination Polymers for Highly Selective Sensing of Cr(III) and Cr(VI) in Water.
Three photoluminescent zinc coordination polymers (CPs), {[Zn2(tpeb)2(2,5-tdc)(2,5-Htdc)2]·2H2O}n(1), {[Zn2(tpeb)2(1,4-ndc)(1,4-Hndc)2]·2.6H2O}n(2), and {[Zn2(tpeb)2(2,3-ndc)2]·H2O}n(3) (tpeb = 1,3,5-tri-4-pyridyl-1,2-ethenylbenzene, 2,5-tdc = 2,5-thiophenedicarboxylic acid, 1,4-ndc = 1,4-naphthalenedicarboxylic acid, and 2,3-ndc = 2,3-naphthalenedicarboxylic acid) were prepared from reactions of Zn(NO3)2·6H2O with tpeb and 2,5-H2tdc, 1,4-H2ndc, or 2,3-H2ndc under solvothermal conditions. Compound 1 has a two-dimensional (2D) grid-like network formed from bridging 1D [Zn(tpeb)]nchains via 2,5-tdc dianions. 2 and 3 possess similar one-dimensional (1D) double-chain structures derived from bridging the [Zn(tpeb)]nchains via pairs of 1,4-ndc or 2,3-ndc ligands. The solid-state, visible emission by 1-3 was quenched by Cr3+, CrO42-, and Cr2O72-ions in water with detection limits by the most responsive complex 3 of 0.88 ppb for Cr3+and 2.623 ppb for Cr2O72-(pH = 3) or 1.734 ppb for CrO42-(pH = 12). These values are well below the permissible limits set by the USEPA and European Union and the lowest so far reported for any bi/trifunctional CPs sensors. The mechanism of Cr3+luminescence quenching involves irreversible coordination to free pyridyl sites in the CP framework, while the Cr6+quenching involves reversible overlap of the absorption bands of the analytes with those of the excitation and/or emission bands for 3.
College of Chemistry, Chemical Engineering and Materials Science, Soochow University , Suzhou 215123, People's Republic of China.|State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , Shanghai 200032, People's Republic of China.
Tian-Yi
TY
Gu
College of Chemistry, Chemical Engineering and Materials Science, Soochow University , Suzhou 215123, People's Republic of China.|Suzhou Clean Environment Institute, Jiangsu Sujing Group Company, Limited, Suzhou 215122, People's Republic of China.
Ming
M
Dai
Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast , Maroochydore DC, Queensland 4558, Australia.
David James
DJ
Young
College of Chemistry, Chemical Engineering and Materials Science, Soochow University , Suzhou 215123, People's Republic of China.
Zhi-Gang
ZG
Ren
College of Chemistry, Chemical Engineering and Materials Science, Soochow University , Suzhou 215123, People's Republic of China.|State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , Shanghai 200032, People's Republic of China.
Jian-Ping
http://orcid.org/0000-0003-2942-7385
JP
Lang