Multistimuli-responsive multicolor solid-state luminescence tuned by NH-dependent switchable hydrogen bonds

Revealing the stimuli-responsive mechanism is the key to the accurate design of stimuli-responsive luminescent materials. We report herein the multistimuli-responsive multicolor solid-state luminescence of a new dicopper(I) complex [{Cu(bpmtzH)}₂(μ-dppa)₂](ClO₄)₂ (1), and the multistimuli-responsive mechanism is clarified by investigating its four different solvated compounds 1·2CH₃COCH₃·2H₂O, 1·2DMSO·2H₂O, 1·4CH₃OH, and 1·4CH₂Cl₂. It is shown that luminescence mechanochromism is associated with the breakage of the hydrogen bonds of bmptzH-NH with counter-ions such as ClO₄^- induced by grinding, while luminescence vapochromism is attributable to the breaking and forming of hydrogen bonds of dppa-NH with solvents, such as acetone, dimethylsulfoxide, and methanol, caused by heating and vapor fuming. In addition, those results might provide new insights into the design and synthesis of multistimuli-responsive multicolor luminescent materials by using various structure-sensitive functional groups, such as distinct N-H ones, to construct switchable hydrogen bonds.