Highly Regioselective Cyclodehydrogenation of Diphenylporphyrin on Metal Surfaces
Yong Zhang, Jianchen Lu, Hangjing Zhou, Guang Zhang, Zilin Ruan, Yi Zhang, Hui Zhang, Shijie Sun, Geifei Niu, Boyu Fu, Bing Yang, Long Chen, Lei Gao, Jinming Cai
Abstract
Exploring the effect of porphin tautomerism on the regioselectivity of its derivatives is a big challenge, which is significant for the development and application of porphyrin drugs. In this work, we demonstrate the regioselectivity of 2 H -diphenylporphyrin (H 2 -DPP) in the planarization reaction on Au(111) and Ag(111) substrates. H 2 -DPP monomer forms two configurations ( anti- and syn- ) via a dehydrogenation coupling, between which the yield of the anti -configuration exceeds 90%. Using high-resolution scanning tunneling microscopy, we visualize the reaction processes from the H 2 -DPP monomer to the final two planar products. Combined with DFT calculations of the potential reaction pathway and comparative experiments on Au(111) and Ag(111) substrates. Using M-DPP (M = Cu and Fe), we confirm that the regioselectivity of H 2 -DPP is derived from the reaction energy barrier during the cyclodehydrogenation reaction of different tautomers. This work reveals the regioselectivity mechanism of H 2 -DPP on the atomic scale, which holds great significance for understanding the chemical conversion process of organic macrocyclic molecules.