Stability Analysis of Pyridine Complexes with Homo‐ and Heterometallic (Cu, Ag, Au) Dimers: A Perspective From SAPT

Metal–ligand interactions, particularly those involving noble metals, have not been extensively studied using energy decomposition analysis frameworks. Noble metals—Pyridine (Py) interactions are very interesting since this ligand has been used as a probe to sense metal nanoparticles' activity and optical properties. Understanding the nature of Cu, Ag, and Au interactions with Py is especially relevant for spectroscopic applications, such as Surface‐Enhanced Raman Spectroscopy, where metal–ligand interactions play a critical role in signal enhancement and selectivity. This work uses a simple model of homometallic and heterometallic noble metal dimers in interaction with Py, and with supermolecular and SAPT schemes, we evaluate the strength of the XCu, XAg, and XAu–Py (XCu, Ag, Au) interactions. The potential energy surface across metal–Py distances was obtained using the PBE0, SAPT2+(CCD)δMP2, SAPT2+(CCD)δMP2 and SAPT2+(3)(CCD)δMP2 methods and was systematically compared against reference data obtained at the CCSD(T) level of theory. No single SAPT method universally reproduces the high‐level CCSD(T) reference interaction energies across all metal–Py complexes analyzed. The bonding in XCu–Py complexes exhibits a predominantly electrostatic character, for which SAPT2+(CCD)δMP2 yields excellent agreement with CCSD(T) data. In contrast, accurate modeling of XAu–Py interactions requires an appropriate description of dispersion forces, making dispersion‐inclusive SAPT variants: SAPT2+(3)δMP2, SAPT2+(3)(CCD)δMP2, essential. XAg–Py complexes exhibit intermediate behavior between the two extremes. The most stabilized metal–Py interactions correspond to those exhibiting the largest induction energy contributions. Furthermore, the extent of orbital overlaps at equilibrium structures may significantly influence overall stability.