Displacement assay detection by a dimeric lanthanide luminescent ternary Tb(III)-cyclen complex: high selectivity for phosphate and nitrate anions

作者：Caffrey David F; Gunnlaugsson Thorfinnur^*

来源：Dalton Transactions, 2014, 43(48): 17964-17970.

DOI：10.1039/c4dt02341b

The luminescent dimeric ternary lanthanide-cyclen complexes (2-(Ln.1)(2); Ln = Tb/Eu) were designed and both their self-assembly formation and their ability to detect anions via displacement assays were investigated using spectrophotometric titrations in MeOH solution. The formation of 2-(Tb.1)(2) and 2-(Eu.1)(2) was investigated in solution, and determination of the binding constants and stoichiometry showed that the former was formed almost exclusively over the 1 : 1 complex 2-(Tb.1) after the addition of two equivalents of 2; while for 2-(Eu.1)(2) a mixture of both stoichiometries existed even after the addition of four equivalents of 2. Of these two systems, 2-(Tb.1)(2) was studied in details as a probe for anions, where significant changes where observed in the photophysical properties of the complex; with the characteristic Tb(III)-centred emission being fully switched off upon the sensing of phosphates and nitrate, giving rise to the formation of a H2PO4 : Tb.1 complex in a 1 : 2 stoichiometry upon sensing of H2PO4 by 2-(Tb.1)(2), while NO3- gave 1 : 1 complex formation and two equivalents of NO3-center dot Tb.1.

• 出版日期2014