Figure 1: Topology diagrams for the design of COFs.
(a) Conventional [1+1] two-component diagram with one knot and one linker for the synthesis of hexagonal and tetragonal COFs. The knots are shown as C3 and C4-symmetric bars, and the linkers are shown as C2-symmetric bars. TP and NiPc are typical C3 and C4-symmetric knots. (b) Polygon geometric transformation on stretching of regular C6-symmetric hexagons and C4-symmetric tetragons into their corresponding C2-symmetric polygons. (c) Our multiple-component [1+3] or [1+4] strategy for the synthesis of hexagonal and tetragonal multiple-component COFs (MC-COFs). Three linkers shown in different colours and with different lengths are used to illustrate the typical knot-linker combinations in the MC strategy. The linkers are asymmetrically tiled to generate sequenced networks and specially shaped pores that are completely unlike from those of conventional COFs.
