title: Dual changes in conformation and optical properties of fluorophores within a metal-organic framework during framework construction and associated sensing event.
abstract: Microsized chemosensor particle (CPP-16, CPP means coordination polymer particle), which is made from a metal-organic framework (MOF), is synthesized using pyrene-functionalized organic building block. This building block contains three important parts, a framework construction part, a Cu(2+) detection part, and a fluorophore part. PXRD studies have revealed that CPP-16 has a 3D cubic structure of MOF-5. During both MOF formation and sensing event, fluorophores within CPP-16 undergo dual changes in conformation and optical properties. After MOF construction, pyrene moieties experience an unusual complete conversion from monomer to excimer form. This conversion takes place due to a confinement effect induced by space limitations within the MOF structure. The selective sensing ability of CPP-16 on Cu(2+) over many other metal ions is verified by emission spectra and is also visually identified by fluorescence microscopy images. Specific interaction of Cu(2+) with binding sites within CPP-16 causes a second conformational change of the fluorophores, where they change from stacked excimer (CPP-16) to quenched excimer states (CPP-16·Cu(2+)).
authors.affiliation: Department of Chemistry, Yonsei University , 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749, Korea.
authors.forename: Won
authors.initials: W
authors.lastname: Cho
authors.forename: Hee Jung
authors.initials: HJ
authors.lastname: Lee
authors.forename: Goeun
authors.initials: G
authors.lastname: Choi
authors.forename: Sora
authors.initials: S
authors.lastname: Choi
authors.forename: Moonhyun
authors.initials: M
authors.lastname: Oh