  Covalent organic frameworks (COFs) are a promising material for various
applications such as gas storage/separation, catalysis, and energy storage,
besides offering a confined space for chemical reaction. The introduction of
unconventional elements into their frame structures and expanding their
structural scope remains a major challenge in COF chemistry. Here, we present
syntheses of two-dimensional and liner COFs substructures linked with
1,4-disilabenzene (C4Si2) by co-depositing silicon atoms and bromo-substituted
poly aromatic hydrocarbons on Au(111). A combination of high-resolution
scanning tunneling microscopy, photoelectron spectroscopy and density
functional theory calculations reveal the detailed structures of the
Si-incorporated COF, as well as its chemical properties. We find that each Si
in a hexagonal C4Si2 ring is terminated by one Br atom. Furthermore, the C4Si2
ring can be transformed to the C4Si pentagonal ring by annealing. Silabenzene
incorporated COFs may open up new possibilities in organosilicon chemistry and
a wide range of practical applications.
