Sensitive Current Sensor Based on a Lanthanide Framework with Lewis Basic Bipyridyl Sites for Cu2+ Detection

A new Yb-based three-dimensional metal-organicframeworkwith free Lewis basic sites, [Yb-2(ddbpdc)(3)(CH3OH)(2)] (referred to as ACBP-6), from YbCl3 and (6R,8R)-6,8-dimethyl-7,8-dihydro-6H-[1,5]dioxonino[7,6-b:8,9-b ']dipyridine-3,11-dicarboxylic acid (H(2)ddbpdc)was synthesized by a conventional solvothermal method. Two Yb3+ are connected by three carboxyl groups to form the [Yb-2(CO2)(5)] binuclear unit, which is furtherbridged by two carboxyl moieties to produce a tetranuclear secondarybuilding unit. With further ligation of the ligand ddbpdc(2-), a 3-D MOF with helical channels is constructed. In the MOF, Yb3+ only coordinates with O atoms, leaving the bipyridyl N atomsof ddbpdc(2-) unoccupied. The unsaturated Lewis basicsites make this framework possible to coordinate with other metalions. After growing the ACBP-6 in situ into a glass micropipette,a novel current sensor is formed. This sensor shows high selectivityand a high signal-to-noise ratio toward Cu2+ detectionwith a detection limit of 1 mu M, due to thestronger coordination ability between the Cu2+ and thebipyridyl N atoms. Asensitive current sensor was rationally designed and successfullysynthesized based on a three-dimensional Yb(III)-MOF, ACBP-6. ACBP-6has a one-dimensional channel with free Lewis basic bipyridyl sitesand exhibits high selectivity and signal-to-noise ratio for the detectionof Cu2+.

Automated summary

A novel Yb-based three-dimensional metal-organic framework (ACBP-6) with free Lewis basic sites was synthesized and used to construct a sensitive current sensor. The sensor exhibited high selectivity and signal-to-noise ratio for Cu2+ detection with a detection limit of 1 μM.