Synthesis of a cyclen-containing disubstituted polyacetylene with strong green photoluminescence and its application as a sensitive chemosensor towards sulfide anion with good selectivity and high sensitivity

Through a postfunctional method, a new disubstituted polyacetylene (P2) bearing cyclen moieties in the side chains, was prepared conveniently and exhibited strong green fluorescence. P2 showed good pH stability in the solution mixture of THF/H₂O (v/v = 1 : 1), and could report the presence of trace Cu²⁺ ions at a concentration as low as 1.0 × 10⁻⁷ mol L⁻¹ in diluted solutions, through an on–off mode. By utilizing the displacement strategy, due to the much higher stability constant of the complex of S²⁻ and Cu²⁺, the quenched fluorescence of P2 by Cu²⁺ ions could recover upon the addition of trace S²⁻ anions, with a detection limit down to 2.0 × 10⁻⁷ mol L⁻¹. Excitingly, no interference was observed from other anions, including AcO⁻, SO₃²⁻, HSO₃⁻, HCO₃⁻, CO₃²⁻, I⁻, Br⁻, Cl⁻, F⁻, S₂O₃²⁻, C₂O₄²⁻, P₂O₇⁴⁻, SCN⁻, HSO₄⁻, SO₄²⁻, NO₂⁻, H₂PO₄⁻, HPO₄²⁻, PO₄³⁻, ClO₄⁻, Cr₂O₇²⁻, S₂O₈²⁻, ClO₃⁻, IO₃⁻, CN⁻ and NO₃⁻, making P2 a new, sensitive and selective sulfide probe.