Zero-Valent Nickel Stabilized in Surface-Supported Metal-Organic Chains.

The stabilization of zero-valent nickel Ni(0) centers in extended coordination networks remains a major challenge due to their pronounced reactivity and susceptibility to oxidation. Here, we demonstrate that linear coordination confinement within a surface-supported metal-organic chain enables the stabilization of Ni(0) atoms on Ag(100). The symmetry of 9,10-dicyanoanthracene (DCA), combined with substrate templating effects, directs the formation of an ordered linear Ni-DCA coordination motif. Spectroscopic measurements provide unambiguous evidence for a formal Ni(0) oxidation state, representing a rare realization of a zero-valent transition metal center within an extended, atomically defined system. The electronic structure is governed by hybridization between Ni 3d orbitals and the π-system of DCA, resulting in an anisotropic electronic dispersion with predominantly one-dimensional character. These results establish linear coordination as a strategy to stabilize reactive, low-valent metal centers in surface-supported metal-organic architectures.