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

The unraveling of the stimuli-responsive mechanism iscrucial tothe design and precise synthesis of stimuli-responsive luminescentmaterials. We report herein the mechanochromic and selective vapochromicsolid-state luminescence properties of a new bimetallic cuprous complex[{Cu(bpmtzH)}(2)(& mu;-dppm)(2)](ClO4)(2) (1), and the corresponding response mechanismsare elucidated by investigating its two different solvated polymorphs 1 & BULL;2CH(2)Cl(2) (1-g) and 1 & BULL;2CHCl(3) (1-c). Green-emissive 1-g and cyan-emissive 1-c can be interconvertedupon alternate exposure to CHCl3 and CH2Cl2 vapors, which is principally attributable to a combined alterationof both intermolecular NHbpmtzH & BULL;& BULL;& BULL;OClO3 (-) hydrogen bonds and intramolecular triazolyl/phenyl& pi;& BULL;& BULL;& BULL;& pi; interactions induced by differentsolvents. Solid-state luminescence mechanochromism present in 1-g and 1-c is mainly ascribed to the grinding-inducedbreakage of the NHbpmtzH & BULL;& BULL;& BULL;OClO3 (-) hydrogen bonds. It is suggested that intramolecular & pi;& BULL;& BULL;& BULL;& pi;-triazolyl/phenyl interactions areaffected by different solvents but not by grinding. The results providenew insights into the design and precise synthesis of multi-stimuli-responsiveluminescent materials by the comprehensive use of intermolecular hydrogenbonds and intramolecular & pi;& BULL;& BULL;& BULL;& pi; interactions. Selective vapochromic luminescence andmechanochromic luminescenceare mainly associated with the changes in intramolecular triazolyl/phenyl & pi;& BULL;& BULL;& BULL;& pi; interactions and/or intermolecularNH(triazolyl)& BULL;& BULL;& BULL;OClO3 (-) hydrogen bonds, while intramolecular triazolyl/phenyl & pi;& BULL;& BULL;& BULL;& pi;interactions can be regulated by different solvents but not by grinding.

Automated summary

The article reports the mechanochromic and selective vapochromic solid-state luminescence properties of a new bimetallic cuprous complex. The response mechanisms are elucidated by investigating the different solvated polymorphs. It is found that the luminescence properties can be controlled by different solvents and grinding-induced breakage of hydrogen bonds.