Synthesis and Luminescence Studies of a Tethered, Trigonal, Silver(I) Tris(alkyne) Complex

The synthesis and characterization of a tris(alkyne) ligand, tris[2-(trimethylsilyl)ethynyl-4-tert-butylbenzyl]amine (1), and its silver(I) hexafluorophosphate complex, 1-Ag, are reported. The solid-state structure and luminescence properties of 1-Ag indicate relatively strong silver(I)-alkyne interactions between the metal cation and 1. No significant changes in the bond angles or lengths were observed upon metalation of 1 with Ag⁺, indicating a relatively unstrained ligand-metal motif. The luminescence properties of 1 and 1-Ag are also disclosed, showing attenuation in the luminescence intensity upon Ag⁺ metalation, with Stokes shifts of ∼3700 and ∼3200 cm^-1 for 1 and 1-Ag, respectively. The lifetimes of 1-Ag (τ₁ = 8.383 ± 0.053 ns and τ₂ = 4.665 ± 0.061 ns) were longer than those of 1 (τ₁ = 6.708 ± 0.085 ns and τ₂ = 3.689 ± 0.025 ns), possibly indicating multiple conformers of 1-Ag in solution. This new silver alkyne platform has potential applications in studies of catalysis, luminescent compounds, and sensing.