Multicolor Organometallic Mechanophores for Polymer Imaging Driven by Exciplex Level Interactions

Photoluminescent
compounds can undergo various structural changes
upon interaction with light. When these changes manifest themselves
in the excited state, the resulting emitters can obtain a sensory
function. In this work, we designed coordination compounds that can
vary their emission color in response to thermal and mechanical stimuli.
When embedded in a polymer matrix, Cu–NHC sensors act as mechanophores,
and their color-based response can readily describe mechanical
stress and phase transition phenomena. A strong practical advantage
of new mechanophores over previous generations of organometallic stress
sensors stems from their reliance on emission color variations that
are easy to detect. In a broad context, our work implies that emission
color variations that we often view as thermally governed can also
be triggered mechanically and used to generate sensory information.