Metal Doping of Au₂₅(SR)₁₈^– Clusters: Insights and Hindsights

Abstract

This is a self-archived version of an original article. This version may differ from the original in pagination and typographic details.

Understanding and controlling the efficiency of Au24M(SR)18nanoclusters as singlet-oxygen photosensitizers

“…46 All clusters were prepared and characterized by mass spectrometry, NMR spectroscopy, and UV-vis spectroscopy as described previously. 39,[48][49][50] Special attention was paid to controlling properly the charge state. 51,52 TREPR experiments were carried out in toluene at 240 K, and refer to 1 mM clusters and 0.5 mM 2,2,6,6-tetramethyl-4-oxo-1-piperidinyloxy (TEM-PONE), unless otherwise stated.…”

“…For these metals, monodoping is conveniently accomplished by carrying out the metal exchange on a preformed Au 25 (SR) 18 À cluster by using a salt or thiolate of the exogenous metal. 39,[72][73][74] We focused on these two metals because they both dope the cluster on one of the icosahedron positions, as we could demonstrate very recently. 39 Monodoping affects the HOMO-LUMO gap.…”

“…39,[72][73][74] We focused on these two metals because they both dope the cluster on one of the icosahedron positions, as we could demonstrate very recently. 39 Monodoping affects the HOMO-LUMO gap. The values that can be estimated from the electrochemical peaks are: 39,70 Au, 1.30 eV; Hg, 1.28 eV; Cd, 1.41 eV.…”

“…39 Monodoping affects the HOMO-LUMO gap. The values that can be estimated from the electrochemical peaks are: 39,70 Au, 1.30 eV; Hg, 1.28 eV; Cd, 1.41 eV. Similar differences are found for the optical bandgaps.…”

“…Besides studying the effect of the protecting ligand, the analysis was extended to monodoped clusters because their optical and especially electrochemical behaviors show signicant differences from those of the undoped clusters. 39 Regarding detection, we relied on continuous-wave and, especially, timeresolved electron paramagnetic resonance techniques (CWEPR and TREPR, respectively). TREPR spectroscopy provides an efficient and sensitive method to detect even very low concentrations of 1 O 2 generated by photosensitization in solution.…”