An international research team, led by NIMS, including Institute for Molecular Science (IMS) and Aalto University in Finland, has succeeded in synthesizing a two-dimensional silicon-integrated covalent organic framework (COF) film on a metal surface. This nanostructure was obtained by linking molecules and silicon atoms using a novel on-surface chemical reaction. This synthesis technique may potentially be applicable to the development of new materials in a bottom-up manner.
Graphical abstract. Credit: Nature Chemistry (2022). DOI: 10.1038/s41557-022-01071-3 COF films with nanosized pores have a wide range of potential applications, from battery materials to catalysts and materials capable of separating small molecules. Imparting these capabilities to COF films requires the substitution of specific carbon atoms within molecular thin films with other chemical elements, such as nitrogen, boron and silicon. Silicon has some advantageous characteristics for these substitutions: it is the second most abundant chemical element by weight in Earth's crust with a Clarke number of 25.8%, it is a group 14 element on the periodic table—as is carbon—and its chemical and physical properties are more similar to those of carbon than any other chemical element. Attempts to develop a method for substituting carbon with silicon in COF films had been unsuccessful, partly because silicon is an inorganic…