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 <b>3</b> 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 <b>3α</b> and <b>3β</b> exhibit emission wavelength maxima (λ_em,max) at 448 and 710 nm, respectively. Upon grinding, the λ_em,max of <b>3α</b>_ground and <b>3β</b>_ground are bathochromically shifted to 900 nm, i.e., Δλ_em,max (<b>3α</b>) = 452 nm or 1.39 eV. Polymorphs <b>3α</b> and <b>3β</b> thus represent the first examples of mechanochromic luminescent materials with λ_em,max in the IR region