Sequential Activation of N–OH and C–H to Yield a Square Metal–Organic Network Featuring Heterogeneous Nodes on Ag(100)

The incorporation of heterogeneous nodes can significantly enhance the catalytic and optoelectronic properties of metal-organic networks (MONs) because of the resulting uneven charge distribution and unique metal centers. On-surface synthesis (OSS) has emerged as a powerful strategy for constructing advanced MONs with heterogeneous metal-organic nodes. Herein, we report the fabrication of an MON featuring N-Ag-C heterogeneous nodes, achieved via thermally induced sequential N-OH and C-H activation on Ag(100). During annealing, dehydroxylation proceeds gradually, leading to the formation of metal-organic dimers, tetramers, and extended chains. Notably, thermal treatment at 530 K triggers C-H activation of the precursor's central benzene ring, yielding an MON containing a rarely observed heterogeneous node. The structural evolution of these species is tracked by scanning tunneling microscopy (STM), complemented by high-resolution synchrotron radiation photoemission spectroscopy (SRPES). This study provides fundamental insights into the design and synthesis of heterogeneous MONs with heterogeneous nodes, paving the way for their potential applications in catalysis and optoelectronics.