Gold Quantum Needles Synthesized by Thermal-Induced, One-Dimensional Oligomerization of Au ₂₄ (SC ₂ H ₄ Ph) ₂₀

Gold quantum needles (AuQNs), which have double-pointed cores Au₁-(Au₃)_2+4<i>n</i>-Au₁ (<i>n</i> = 1, 2, 3, etc.) protected by 2-phenylethanethiolate (PET) ligands, have attracted significant attention due to their unique NIR-responsive properties. Herein we demonstrate that these AuQNs can be synthesized through the long-term heating of a highly concentrated solution of Au₂₄(PET)₂₀ without the use of directing templates. Additionally, we obtained two unprecedented series of AuQNs that exhibit intense absorption in the NIR region as minor products. Based on density functional theory calculations, we propose that these two series of AuQNs possess single-truncated Au₁-(Au₃)_5+4<i>n</i> and double-truncated (Au₃)_4+4<i>n</i> cores, respectively. These novel phenomena illustrate the potential of fusion-based synthesis for creating highly anisotropic gold nanostructures.