Using cuprophilicity as a multi-responsive chromophore switching color in response to temperature, mechanical force and solvent vapors

A novel strategy is provided in this paper to design multi-stimuli-responsive luminescent materials by taking a multi-responsive chromophore which responds to multiple environmental stimuli instead of constructing multi-chromophore systems. Herein, we have successfully prepared a tri-stimuli-responsive luminescent material, [Cu4I4(4-dpda)4] (1), with reversible and independent thermochromism, mechanochromism and vapochromism simultaneously by applying cuprophilic interactions as a multi-responsive chromophore. The organic ligand 4-dpda is chosen to amplify the perturbation toward metallophilic interations for steric hindrance, and many of the molecular interactions of its multi-phenyl moieties are sensitive to tiny disturbances and will translate the effects to the Cu4I4 core of compound 1. Structural and spectrographic investigations show that the changes in luminescence result from the disturbed cuprophilic interactions.