One-Dimensional Silver-Thiolate Cluster-Assembly: Effect of Argentophilic Interactions on Excited-State Dynamics

We
report the synthesis, crystal structure, and electronic structure
calculations of a one-dimensional silver-thiolate cluster-assembled
and its ultrafast spectroscopic investigation. Experiments and theory
find the material to have a significant gap as the HOMO–LUMO
absorption corresponds to 2.69 eV, and the defect-free structure is
calculated to have a gap of 2.82 eV. Cluster models demonstrate that
the gap energy is length-dependent. Theoretical studies identify a
nonbonding metallophilic interaction that exists between two Ag atoms
in adjacent strings that helps to stabilize the chain structure. Transient
absorption spectroscopy reveals that the electron dynamics is a mixture
of the behavior of cluster and nanoparticle, with the material having
a 346 fs ground-state relaxation like a cluster, and the electron
dynamics is dominated by electron–phonon coupling with a decay
time of 1.5 ps, unlike the isolated cluster whose decay is mostly
radiative.