Similarities and differences in the mechanisms alkyne and isonitrile transformations catalyzed by silver ions and nanoparticles

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.

A new silver coordination polymer based on 4,6-diamino-2-pyrimidinethiol: synthesis, characterization and catalytic application in asymmetric Hantzsch synthesis of polyhydroquinolines

A highly efficient and stable heterogeneous coordination polymer (CP) was successfully prepared by hydrothermal combination of silver and 4,6-diamino-2-pyrimidinethiol. The prepared coordination polymer was characterized by FT-IR, XRD, TGA, SEM, EDX, X-ray mapping and Nitrogen adsorption–desorption analysis. The prepared Ag–CP exhibit excellent catalytic activity in multicomponent Hantzsch synthesis of polyhydroquinolines under mild reaction conditions in relatively short reaction times. The heterogeneity of the catalyst was confirmed by the hot filtration test; also, the catalyst was reused for at least four times under the optimized reaction conditions without any significant loss of its catalytic activity.