Progress in mechanochromic luminescence of gold(I) complexes

Photophysical properties of organic and organometallic luminophors are closely related with their molecular packings, enabling the exploitation of stimuli-responsive functional luminescent molecules. Mechanochromic molecules, which can change their luminescence characteristics after mechanical stimulus, have received an increasing interest due to their promising applications in multifunctional sensors and molecular switches. During the past two decades, the development of gold(I) chemistry has been attracting the attention of plenty of researchers. Indeed, a variety of gold(I) complexes with fascinating photophysical behaviors have been discovered. This review focuses on the research progress in the different types of mechanoluminochromic gold(I) complexes, including mono-, bi- and multi-nuclear gold(I) systems. Their interesting luminescence behaviors of these gold(I)-containing luminogens upon mechanical stimulus and the proposed mechanisms of their observed mechanochromic luminescence are summarized systematacially. Moreover, this review will put forward an outlook about the possible opportunities and challenges in this significative scientific field.