Mechanochromic and Selective Vapochromic Solid-State Luminescence of a Dinuclear Cuprous Complex.

The unraveling of the stimuli-responsive mechanism is crucial to the design and precise synthesis of stimuli-responsive luminescent materials. We report herein the mechanochromic and selective vapochromic solid-state luminescence properties of a new bimetallic cuprous complex [{Cu(bpmtzH)} 2 (μ-dppm) 2 ](ClO 4 ) 2 ( 1 ), and the corresponding response mechanisms are elucidated by investigating its two different solvated polymorphs 1 ·2CH 2 Cl 2 ( 1-g ) and 1 ·2CHCl 3 ( 1-c ). Green-emissive 1-g and cyan-emissive 1-c can be interconverted upon alternate exposure to CHCl 3 and CH 2 Cl 2 vapors, which is principally attributable to a combined alteration of both intermolecular NH bpmtzH ···OClO 3 - hydrogen bonds and intramolecular "triazolyl/phenyl" π···π interactions induced by different solvents. Solid-state luminescence mechanochromism present in 1-g and 1-c is mainly ascribed to the grinding-induced breakage of the NH bpmtzH ···OClO 3 - hydrogen bonds. It is suggested that intramolecular π···π-triazolyl/phenyl interactions are affected by different solvents but not by grinding. The results provide new insights into the design and precise synthesis of multi-stimuli-responsive luminescent materials by the comprehensive use of intermolecular hydrogen bonds and intramolecular π···π interactions.