A <i>N</i>‑Heterocyclic Carbene-Stabilized Coinage Metal-Chalcogenide Framework with Tunable Optical Properties
journal contribution
posted on 2017-09-27, 18:18 authored by Alexander
M. Polgar, Florian Weigend, Angel Zhang, Martin J. Stillman, John F. CorriganA new class of coinage-metal chalcogenide
compounds [Au<sub>4</sub>M<sub>4</sub>(μ<sub>3</sub>-E)<sub>4</sub>(IPr)<sub>4</sub>] (M = Ag, Au; E = S, Se, Te) has been synthesized
from the combination
of <i>N</i>-heterocyclic carbene-ligated gold(I) trimethylsilylchalcogenolates
[(IPr)AuESiMe<sub>3</sub>] and ligand-supported metal acetates. Phosphorescence
is observed from these clusters in glassy 2-methyltetrahydrofuran
and in the solid state at 77 K, with emission energies that depend
on the selection of metal/chalcogen ion composition. The ability to
tune the emission is attributed to electronic transitions of mixed
ligand-to-metal-metal-charge-transfer (IPr → AuM<sub>2</sub>) and interligand (IPr → E) phosphorescence character, as
revealed by time-dependent density functional theory computations.N-heterocyclic
carbenes (NHCs) have been applied as ancillary ligands in the synthesis
of luminescent gold(I) chalcogenide clusters and this approach allows
for unprecedented selectivity over the metal and chalcogen ions present
within a stable octanuclear framework.
