Table 1_Aurophilicity as a structure-directing principle in hyperchlorinated AunCln+5- (2 ≤ n ≤ 7) clusters.docx

<p>This study addresses the gap concerning the structural landscape of experimentally observed high-chloride Au_nCl_n+5^- cluster anions, whose stable geometries, aurophilic interaction patterns, thermodynamic stability, and growth pathways remain largely unexplored compared to well-characterized low- and medium-chloride analogues. To resolve this, we systematically investigate Au_nCl_n+5^- (n = 2–7) using laser desorption/ionization mass spectrometry (LDI-MS) and density functional theory at the TPSSh/aug-cc-pVTZ/ECP60MDF level.

The results show that elevated laser intensity preferentially stabilizes these chlorine-rich clusters. Except for the smallest cluster (Au₂Cl₇⁻), the global minima adopt nearly planar zigzag geometries, where terminal gold atoms are in a tetracoordinate Au(III) state and internal gold atoms are in an Au(I) state. Bond-length analysis reveals that only non-terminal Au–Au distances are significantly shorter than the van der Waals sum, indicating aurophilic attraction, while terminal distances show no such interaction.