Stimuli-Responsive Luminescent Properties of Dinuclear Cu(I) Complexes Regulated by Hydrogen-Bonding Donors

The selection of hydrogen-bonding donors is crucial for the development of stimuli-responsive luminescent materials that rely on weak hydrogen-bonding interactions. In this study, we report two novel dinuclear Cu(I) complexes, [Cu₂(μ-η²(<i>N</i>,<i>N</i>),η²(<i>N</i>,<i>N</i>)-dpa)(μ-dppm)₂](ClO₄) (<b>1</b>) and [Cu₂(μ-η²(<i>N</i>,<i>N</i>),η²(<i>N</i>,<i>N</i>)-dpa)(μ-dppa)₂](ClO₄)·2CH₃COCH₃ (<b>2</b>), which differ in their diphosphine linkers (CH₂ in dppm vs NH in dppa). X-ray crystallography reveals weak CH···O hydrogen bonds between dppm-CH₂ and perchlorate-O in <b>1</b> and weak NH···O interactions between dppa-NH and acetone-O in <b>2</b>. The destruction of CH···OClO₃^- hydrogen bonds in <b>1</b>, induced by grinding, triggers mechanochromic luminescence. In <b>2</b>, the disruption of NH···OC(CH₃)₂ hydrogen bonds, caused by heating and grinding, leads to both thermochromic and mechanochromic luminescence. It is demonstrated that differences in donor-acceptor pairing (CH₂/ClO₄^- vs NH/acetone) influence the nature and responsiveness of hydrogen-bonding interactions. Furthermore, these results offer new insights into the design and synthesis of low-cost, multistimuli-responsive luminescent materials through the modification of hydrogen-bonding donors.