Synthesis of extended covalently bound porphyrins on the Au(111) surface

Abstract

Solution deposition of a 5,10,15,20-tetrakis-(4-bromophenyl)-porphyrin (TBrPP) and dichloromethane (DCM) on the Au(111) surface produces self-assembled islands with a non-random orientation that is directed by the gold herringbone reconstruction of Au(111). Annealing to 230 °C caused approximately 1/3 of the surface adsorbed porphyrins to interact with the underlying gold adatom leading to Au-TBrPP intermediates. The position of the TBrPP molecules corresponded with the soliton walls of the gold herringbone reconstruction. Annealing to 300 °C caused dehalogenated C–C coupling between TBrPP and DCM as well as the metalation of TBrPP. This reaction created polymeric chains of TBrPP with DCM linkers. The molecular chains are flexible and can be easily manipulated using a scanning tunneling microscope (STM) tip.