title: Highly sensitive and selective fluorescent probes for Hg2+in Ag(i)/Cu(ii) 3D supramolecular architectures based on noncovalent interactions.
abstract: Three novel metal-organic assemblies (MOAs), namely, [Ag(2,4'-Hpdc)(4,4'-bpy)]n(1), [Ag(2,2'-Hpdc)(4,4'-bpy)0.5]n(2), and [Cu(2,2'-Hpdc)2(1,4-bib)]n(3) [2,4'-H2pdc = 2,4'-biphenyldicarboxylic acid; 2,2'-H2pdc = 2,2'-biphenyldicarboxylic acid; 4,4'-bpy = 4,4'-bipyridine; 1,4-bib = 1,4-bis(1-imidazolyl)benzene] have been hydrothermally synthesized by using mixed ligands and characterized by single crystal X-ray diffraction, infrared (IR), elemental analysis and thermogravimetric analysis (TGA). The crystal structures of the three compounds indicate that the hydrogen bonding (C-HO and C-Hπ) and ππ stacking interactions play critical roles in the formation of an extended supramolecular array. The combination of C-Hπ and ππ stacking interactions endow 1 with a 3D network. 2 displays a rare 3D structure with a unique 1D structure based on an eight-membered {Ag2C2O4} ring and compound 3 shows a 1D chain structure, which is propagated to form an extended 3D structure only by C-Hπ hydrogen bonding. The two Ag(i)-compounds display blue emissions in the solid state at 298 K and 77 K. More significantly, compound 1 shows excellent selectivity, fast detection time (<5 min), and high sensitivity (detection limit, 9.63 nM) for Hg2+ions in aqueous solution due to a great enhancement of 1-luminescence, which can be attributed to Hg2+cation binding by a non-coordinated carboxyl group efficiently. This is a rare example of Hg2+detection in aqueous solution based on luminescent silver MOAs. In addition, adsorption spectra reveal the semiconductive nature (2.76 eV for 2, but not detected for 1), thus the role of the AgAg interaction in controlling the performance of the semiconductor properties is highlighted.
authors.affiliation: MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, PR China. fanruiqing@hit.edu.cn ylyang@hit.edu.cn.
authors.forename: Yang
authors.initials: Y
authors.lastname: Song
authors.affiliation: MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, PR China. fanruiqing@hit.edu.cn ylyang@hit.edu.cn.
authors.forename: Ruiqing
authors.initials: R
authors.lastname: Fan
authors.affiliation: State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150001, PR China. fanjizhuang@hit.edu.cn.
authors.forename: Jizhuang
authors.initials: J
authors.lastname: Fan
authors.affiliation: MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, PR China. fanruiqing@hit.edu.cn ylyang@hit.edu.cn.
authors.forename: Kai
authors.initials: K
authors.lastname: Xing
authors.affiliation: MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, PR China. fanruiqing@hit.edu.cn ylyang@hit.edu.cn.
authors.forename: Xi
authors.initials: X
authors.lastname: Du
authors.affiliation: MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, PR China. fanruiqing@hit.edu.cn ylyang@hit.edu.cn.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.affiliation: MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, PR China. fanruiqing@hit.edu.cn ylyang@hit.edu.cn.
authors.forename: Yulin
authors.initials: Y
authors.lastname: Yang