Luminescent heterobimetallic Au(I)/Ag(I) complex stabilized by a unique acetylide fragment: A spectroscopic and computational study of aurophilic ‒ argentophilic interactions

Abstract

This paper investigates the luminescence and metallophilic interaction in the heterobimetallic Au(I)-Ag(I) acetylide cluster [Au2Ag2(CCPh)4(PPh3)2]. Analysis using single-crystal X-rays shows short Au∙∙∙Ag separations (2.8806(3)-3.0212(3) Å), showing favorable closed shell (d10⋯d10) aurophilic-argentophilic interactions. DFT calculations and ELF analysis reveal electron localization between Au⋯Ag contacts and electron density dispersion around gold and silver ions. Quantum Theory of Atoms in Molecules (QTAIM) research reveals electron density at bond critical points (bcp) and assesses Au(I)⋯Ag(I) interaction strengths. Natural Bond Orbital (NBO) analysis identifies donor–acceptor characteristics of orbitals involved in aurophilic ‒ argentophilic interactions.