Synergistic coordination of diphosphine with primary and tertiary phosphorus centers: Ultrastable icosidodecahedral Ag30 nanoclusters with metallic aromaticity | Science Advances

As versatile ligands with extraordinary coordination capabilities, RPH ₂ (R = alkyl or aryl) are rarely used in constructing metal nanoclusters due to their volatility, toxicity, spontaneous flammability, and susceptibility to oxidation. In this work, we designed a primary and tertiary phosphorus-bound diphosphine chelator (2-Ph ₂ PC ₆ H ₄ PH ₂ ) to create ultrastable silver nanoclusters with metallic aromaticity. By controlling the deprotonation rate of 2-Ph ₂ PC ₆ H ₄ PH ₂ and adjusting the templates, we successfully synthesized two near-infrared emissive nanoclusters, Ag30 and Ag32 , which have analogous icosidodecahedral Ag ₃₀ shells with an I _h symmetry. Deprotonated ligand (2-Ph ₂ P _α C ₆ H ₄ P _β ²⁻ ) exhibits a coordination mode of μ ₅ -η ¹ (P _β ),η ² (P _α ,P _β ), which endows a unique metallic aromaticity to Ag30 and Ag32 . The solution-processed organic light-emitting diodes based on Ag30 achieve an external quantum efficiency of 15.1%, representing the breakthrough in application of silver nanoclusters to near-infrared–emitting devices. This work represents a special ligand system for synthesizing ligand-protected coinage metal nanoclusters and opens up horizons of creating nanoclusters with distinct geometries and metal aromaticity.