Synthesis of Metallopolymers and Direct Visualization of the Single Polymer Chain

Abstract

During the past few decades, the study of single polymer chain has attracted considerable attentions with the goal of exploring the structure-property relationship of polymers. It still, however, remains challenging due to the variability and low atomic resolution of amorphous single polymer chain. Here, we demonstrated a new strategy to visualize single metallo-polymer chain with hexameric or trimeric supramolecule as repeat unit, in which Ru(II) with strong coordination and Fe(II) with weak coordination were combined together in a step-wise manner. With the help of ultrahigh-vacuum, low-temperature scanning tunneling microscopy (UHV-LT-STM) and scanning tunneling spectroscopy (STS), we were able to directly visualize both Ru(II) and Fe(II), which act as staining reagents on the repeat units, and thus providing de-tailed structure information for the single polymer chain. As such, the direct visualization of single random polymer chain is realized to enhance the characterization of polymers at single-molecule level.