Stress-responsive properties of metallocenes in metallopolymers
In this review, we focus on metallocenes (e.g., ferrocene, ruthenocene, and cobaltocene/cobaltocenium), a class of prototypical organometallic compounds, as emerging stress-responsive building blocks for materials. In particular, they are used in the field of polymers as molecular ball-bearings, redox molecular motors, and mechanophores in response to varied force stimulus intensities. We present a workflow for a stress-responsive metallocene, the research techniques in various material phases, the factors impacting their mechanosensitivity, and the functional applications. Future prospects are briefly highlighted. This review provides fresh viewpoints and mechanistic insights to stimulate further studies in this field.