A new highly selective fluorescent silver probe.

We have synthesized 3,3,7,7-tetra[N-ethyl-N-benzyl(acetamide)-2-oxymethyl]-5- oxanonane (EBAOO) and its terbium complex. The crystal structures of the complex were determined: [Tb(EBAOO)](2)[Tb(NO(3))(5)](3).H(2)O, Orthorhombic, a=40.722 (6) A, b=18.418 (3) A, c=20.496 (3) A. In the structure, the rare earth ion satisfies nine coordination. The geometry of the nine-coordinate polyhedron is discussed in terms of the dihedral angle and the mean plane. The luminescence of the complex is noticeably enhanced upon complexation with Ag(+), which is due to the suppression of photoinduced electron transfer (PET) process. Therefore, the terbium complex can be used as a selective fluorescent silver probe.