On-surface synthesis of Au–C4 and Au–O4 alternately arranged organometallic coordination networks via selective aromatic C–H bond activation

Abstract

Selective activation of the C–H bond of aromatic hydrocarbons is significant in synthetic chemistry. However, achieving oriented C–H activation remains challenging due to the poor selectivity of aromatic C–H bonds. Herein, we successfully constructed alternately arranged Au–C4 and Au–O4 organometallic coordination networks through selective aromatic C–H bond activation on Au(111) substrate. The stepwise reaction process of the 5, 12-dibromopyrene 3,4,9, 10-tetracarboxylic dianhydride precursor is monitored by high-resolution scanning tunneling microscopy. Our results show that the gold atoms in C–Au–C organometallic chains play a crucial role in promoting the selective ortho C–H bonds activation and forming Au–C4 coordination structure, which is further demonstrated by a comparative experiment of PTCDA precursor on Au(111). Furthermore, our experiment of 2Br-PTCDA precursor on Cu(111) substrate confirms that copper atoms in C–Cu–C organometallic chains can also assist the formation of Cu–C4 coordination structure. Our results reveal the vital effect of organometallic coordination on selective C–H bond activation of reactants, which holds promising implications for controllable on-surface synthesis.