title: A silver-alkynyl cluster encapsulating a fluorescent polyoxometalate core: enhanced emission and fluorescence modulation.
abstract: A new silver(I)-alkynyl cluster with a [Eu(W5O18)2](9-) polyoxoanionic core of [Ag42{Eu(W5O18)2}((t)BuC≡C)28Cl4] [OH]·H2O (1) has been designed and synthesized. The [Eu(W5O18)2](9-) polyoxoanion acts as a template to induce the formation of the surrounding 42-core Ag(I) cage. Due to the hydrophobic silver(I)-alkynyl shell, 1 features an unusual fluorescence enhancement as compared to the precursor of the [Eu(W5O18)2](9-) polyoxoanionic core. Interestingly, the silver ions in the shell silver(I)-alkynyl cage can only be reduced to silver atoms by irradiation with high energy UV light (2 kW). Upon high UV irradiation, fluorescence quenching of 1 has been observed. Moreover, the solution fluorescence of 1 can be modulated by addition of S(2-) ions into the system, which also leads to the fluorescence quenching phenomenon. The successful synthesis of 1 demonstrates a new route to the detection of high energy UV irradiation or S(2-) ions by elaborate design of fluorescence quenching of silver(I)-alkynyl clusters.
authors.affiliation: Department of Chemistry, College of Pharmacy, Jiamusi University, Jiamusi 154004, China. hliu@jmsu.edu.cn gaogg@jmsu.edu.cn.
authors.forename: Chao-Yu
authors.initials: CY
authors.lastname: Song
authors.forename: Dong-Feng
authors.initials: DF
authors.lastname: Chai
authors.forename: Rui-Ren
authors.initials: RR
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Yun-Feng
authors.initials: YF
authors.lastname: Qiu
authors.forename: Hua-Dong
authors.initials: HD
authors.lastname: Guo
authors.forename: Guang-Gang
authors.initials: GG
authors.lastname: Gao
mesh_terms: D005063:Europium / Q000737:chemistry* / Q000528:radiation effects; D005453:Fluorescence; D012834:Silver / Q000737:chemistry* / Q000528:radiation effects; D017973:Tungsten Compounds / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D017973:Tungsten Compounds; D012834:Silver; D005063:Europium