A gas-phase synthesis of Ag-centered phenylenediamine clusters

Abstract

Small Ag_n⁺ clusters were prepared using a customized magnetron sputtering (MagS) cluster source, and their reactions with aromatic amine molecules were observed using a reflection time-of-flight mass spectrometer (TOF-MS). Interestingly, it was found that o-phenylenediamine (OPD) and m-phenylenediamine (MPD) readily reacted with the small Ag_n⁺ (n = 1–3) clusters, resulting in the formation of [Ag(OPD)_1–2]⁺ and [Ag(MPD)_1–3]⁺ complexes. In contrast, p-phenylenediamine (PPD) was relatively inert with reaction products rarely being observed. Employing DFT calculations, we illustrated the altered electrostatic interaction distribution and orbital overlap correlation, which account for the diversity in forming N–Ag⁺–N complexes or simply hosting a metal ion around the aromatic ring. Further, utilizing the soft-landing deposition technique, we prepared mass-selected cluster deposits and conducted a Raman spectroscopic study.