Expression of concern for 'Synthesis and characterization of a novel copper carboxylate complex and a copper complex-coated polyether sulfone membrane for efficient degradation of methylene blue dye under UV irradiation: the single crystal X-ray structure of the copper carboxylate complex' by Rupy Dhir et al., Dalton Trans., 2024, 53, 9441-9451, https://doi.org/10.1039/D4DT00871E.