Highly selective Fe3+ sensing and proton conduction in a water-stable sulfonate-carboxylate Tb-organic-framework

A new 3D porous terbium-organic framework {[Tb-4(OH)(4)(DSOA)(2)(H2O)(8)]center dot(H2O)(8)}(n) (Tb-DSOA) has been successfully assembled by Tb3+ ions and a sulfonate-carboxylate linker disodium-2,2'-disulfonate-4,4'-oxydibenzoic acid (Na(2)H(2)DSOA). In this metal-organic framework (MOF), tetranuclear terbium clusters can be sensitized by the organic linker to generate the characteristic photoluminescence of Tb-III ions. Noncoordinated sulfonate oxygen atoms functionalize its channels, which act as basic sites leading to highly selective Fe3+ ion sensing by luminescence quenching, and also act as hopping sites for proton transfer, resulting in a proton conductivity of 1.66 x 10(-4) S cm(-1) at 98% RH. Exceptional water-stability makes this MOF compatible for these applications in aqueous solution.