Low-Dimensional Metal-Alkynyls: On-Surface Synthesis and Properties.

Metal-alkynyls, an emerging class of functional metal-organic materials, have attracted widespread attention due to their fascinating properties and multifaceted potential applications, such as luminescence, nonlinear optics, liquid crystals, and catalysis. Despite considerable effort toward their synthesis, precise construction of complex metal-alkynyl structures with a high selectivity remains a great challenge. The rise of on-surface chemistry not only offers a route to realizing controlled synthesis of low-dimensional (LD) metal-alkynyls but also provides an opportunity for their in-depth investigations with advanced surface characterization techniques such as scanning tunneling microscopy. This Perspective presents an overview of some recent progress in precise on-surface synthesis of LD metal-alkynyls. Atomic-level explorations of chemical reactivities and electronic properties of surface-confined metal-alkynyls are then summarized to highlight their conjugated electronic states and rich chemistry.