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

Abstract

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.