Hierarchical formation of Fe-9eG supramolecular networks via flexible coordination bonds

From the interplay between high-resolution scanning tunneling microscopy imaging/manipulations and density functional theory calculations, we display the hierarchical formation of supramolecular networks by codeposition of 9eG molecules and Fe atoms on Au(111) based on the flexible coordination bonds (the adaptability and versatility in the coordination modes). In the first step, homochiral islands composed of homochiral G₄Fe₂ motifs are formed; and then in the second step, thermal treatment results in the transformation into the porous networks composed of heterochiral G₄Fe₂ motifs with the ratio of the components being constant. In situ STM manipulations and the coexistence of some other heterochiral G₄Fe₂ motifs and clusters also show the flexibility of the coordination bonds involved. These studies may provide a fundamental understanding of the regulations of multilevel supramolecular structures and shed light on the formation of designed supramolecular nanostructures.