A smart "off–on" gate for the in situ detection of hydrogen sulphide with Cu(ii)-assisted europium emission. Issue 3 (7th January 2016) - Liang, Zhenhao
Abstract : A novel responsive europium-based luminescence "off–on" gate for the in situ detection of H2 S in water was developed. Abstract : A water-soluble and emissive Eu-complex (EuL1 ) bearing a DO3A(Eu 3+ )–pyridine–aza-crown motif has been prepared and its Cu 2+ complex has been demonstrated to be a smart luminescence "off–on" gate for H2 S detection in water with a nano-molar detection limit (60 nM).EuL1 binds to Cu 2+ ions selectively ( K B = 1.2 × 10 5 M −1 ) inducing 17-fold luminescence quenching and forming a 1 : 1 stoichiometric complex (EuL1 –Cu 2+ ), which responds to H2 S selectively with restoration of the original Eu emission ofEuL1 followed by a further 40-fold luminescence enhancement, forming a 1 : 1 stoichiometric complex (EuL1 –Na2 S, K B = 1.5 × 10 4 M −1 ). Without Cu 2+ ions, EuL1 showed non-specific binding towards H2 S with only a 5-fold luminescence enhancement.