A tetra-nuclear Cu(ii) complex of amide-imine conjugate: highly-selective ESIPT-based probe for OCl−

Abstract

A unique tetra-nuclear Cu(II) complex (C1) was structurally authenticated by single crystal X-ray diffraction; it had a distorted cubane-like core Cu₄O₄ and was derived from amide–imine conjugate to selectively recognize OCl⁻via inhibition of the ESIPT process, resulting in the induction of fluorescence. The H-bond-assisted strong interaction between C1 and OCl⁻ is reflected by the binding constant, 1.52 × 10⁵ M⁻¹, with an LOD of 13.87 nM.