Novel Strategy for Construction of Covalent Organic Frameworks Transformed from Nonporous Covalent Organic Polymers.

The field of covalent organic frameworks (COFs) has been developed significantly in the past decade on account of their important characteristics and vast application potential. On the other hand, the discovery of novel synthetic methodology is still a challenging task to further promote the preparation of COFs. Herein, an interesting protocol for the conversion of amorphous nonporous covalent organic polymers (COPs) to COFs was established, affording four COFs with high crystallinity and porosity. Specifically, imine-linked amorphous COP-1 was successfully converted to COF-1-4 by replacing one type of linker with other organic building blocks. The realization of this conversion provides a facile method for constructing COFs from COPs.