Surface confined synthesis of porphyrin containing two-dimensional polymers: the effect of rigidity and preferential adsorption of building blocks.

We have designed and synthesized two porphyrin containing two-dimensional (2D) polymers based on the imine linkage. Both the 2D polymers are revealed to be 2D organic semiconductors with band gaps of around 1 eV. STM characterization reveals that the rigidity and affinity of building blocks to the surface has essential effects on the topology of the 2D polymers.