Luminescent Mechanochromic 9-Anthryl Gold(I) Isocyanide Complex with an Emission Maximum at 900 nm after Mechanical Stimulation

Upon mechanical stimulation, 9-anthryl gold(I) isocyanide complex 3 exhibited a bathochromic shift of its emission color from the visible to the infrared (IR) region, which is unprecedented in its magnitude. Prior to exposure to the mechanical stimulus, the polymorphs 3 alpha and 3 beta exhibit emission wavelength maxima (lambda(em,max)) at 448 and 710 nm, respectively. Upon grinding, the lambda(em,max) of 3 alpha(ground) and 3 beta(ground) are bathochromically shifted to 900 nm, i.e., Delta lambda(em,max) (3 alpha) = 452 nm or 1.39 eV. Polymorphs 3 alpha and 3 beta thus represent the first examples of mechanochromic luminescent materials with lambda(em,max) in the IR region.