ABSTRACT
Luminescent mechanochromism is a phenomenon where emission colors of solid and liquid crystalline states of organic and organometallic compounds change upon mechanical stimulation such as grinding, pressing, shearing, rubbing, and ball-milling. Such mechanochromic organic and organometallic compounds have potentials for applications in force sensors, probes, optical recording, and displays. Emission color control of mechanochromic compounds is highly challenging subjects for exploration of mechanochromic compounds. As an approach to control emission properties of mechanochromic compounds, the chapter tries to develop new compounds showing photoluminescence at longer wavelength region based on two different methods: systematic introduction of various substituents, and expansion of π-conjugated moieties of the chromophores. It shows the semi-rational control of emission colors of aryl gold isocyanide complexes. In order to develop mechanochromic compounds exhibiting emission at longer wavelength regions, π-conjugated aryl moieties were extended. The results indicate that extension of π-conjugated moieties is more promising compared to the introduction of electron-withdrawing/donating substituents to express photoluminescence at long-wavelength regions.
