Au25(SR)18 (R = −CH2–CH2–Ph) is a molecule-like nanocluster displaying distinct electrochemical and optical features. Although it often taken as an example of particularly well-understood cluster, very recent literature has provided quite unclear or even controversial description its properties. We prepared monodisperse Au25(SR)180 studied by cyclic voltammetry, under controlled conditions, the kinetics reduction oxidation to series charge states, −2, −1, +1, +2, +3. For each electrode...

The study of the structures and properties atomically precise gold nanoclusters is object active research worldwide. Recently, has been also focusing on doping metal through introduction noble metals, such as platinum, less cadmium mercury. Previous studies, which relied extensively use mass spectrometry single-crystal X-ray crystallography, led to assignment location each these foreign-metal atoms. Our provides new insights into this topic and, particularly, compelling evidence about actual...

Au25(SR)18 has provided fundamental insights into the properties of clusters protected by monolayers thiolated ligands (SR). Because its ultrasmall core, 1 nm, displays molecular behavior. We prepared a Au25 cluster capped n-butanethiolates (SBu), obtained structure single-crystal X-ray crystallography, and studied both experimentally theoretically. Whereas in solution Au25(SBu)18(0) is paramagnetic molecule, crystal it becomes linear polymer connected via single Au-Au bonds stabilized...

X-ray crystallography has been fundamental in discovering fine structural features of ultrasmall gold clusters capped by thiolated ligands. For still unknown structures, however, new tools capable providing relevant information are sought. We prepared a 25-gold atom nanocluster protected the smallest ligand ever used, ethanethiol. This cluster displays electrochemistry, mass spectrometry, and UV-vis absorption spectroscopy similar Au25 18 The anionic neutral form Au25(SEt)18 were fully...

Monodisperse Au25L180 (L = S(CH2)2Ph) and [n-Oct4N+][Au25L18–] clusters were synthesized in tetrahydrofuran. An original strategy was then devised to oxidize them: the presence of bis(pentafluorobenzoyl) peroxide, neutral or negatively charged react as efficient electron donors a dissociative electron-transfer (ET) process, former case yielding [Au25L18+][C6F5CO2–]. As opposed other reported redox methods, this ET approach is irreversible, easily controllable, clean, particularly for NMR...

The electrochemical reduction of five dialkyl peroxides in DMF was studied by cyclic voltammetry. electron transfer (ET) to the selected compounds is concerted with oxygen−oxygen bond cleavage (dissociative ET) and independent electrode material. Such an behavior provided opportunity study dissociative ETs using mercury therefore test ET theory heterogeneous activation−driving force relationships. convolution voltammetry analysis coupled double-layer correction led reasonable estimates...

The electrochemical transfer coefficient α is shown to be a sensitive probe of the mechanism by which electron and bond cleavage may coupled in dissociative transfers. particularly useful detecting transition between stepwise concerted Whereas linear potential dependencies are agreement with either mechanism, can evidenced upon observation nonlinear pattern. Under favorable circumstances, wavelike dependence observed. This function main parameters describing competition such as, particular,...

The preparation and properties of a series gold nanoclusters protected by thiolated peptides based on the α-aminoisobutyric acid (Aib) unit are described. were devised to form 0−3 CO···H−N intramolecular hydrogen bonds, as required their 310-helical structure. monolayer-protected clusters (MPCs) prepared, using modified version two-phase Brust−Schiffrin preparation, fully characterized with 1H NMR spectrometry, IR UV−vis absorption spectroscopies, transmission electron microscopy (TEM),...

The monolayer protecting small gold nanoparticles (monolayer-protected clusters, MPCs) is generally represented as the 3D equivalent of 2D self-assembled monolayers (SAMs) on extended surfaces. However, despite growing relevance MPCs in important applied areas, such catalysis and nanomedicine, our knowledge structure SAMs solution still extremely limited. We prepared a large series monodisperse Au25(SCnH2n+1)18 clusters (n=2, 4, 6, 8, 10, 12, 14, 16, 18) studied how electrons tunnel through...

We describe the synthesis, computational analysis, photophysics, electrochemistry and electrochemiluminescence (ECL) of a series compounds formed two triphenylamines linked by fluorene or spirobifluorene bridge. The phenylamine moieties were modified at para-position external rings electron-withdrawing electron-donating substituents. These modifications allowed for fine-tuning photoluminescence (PL) ECL emission from blue to green, with an overall wavelength span 73 67 nm, respectively. For...

The study of the molecular cluster Au25(SR)18 has provided a wealth fundamental insights into properties clusters protected by thiolated ligands (SR). This is also because this been particularly stable under number experimental conditions. Very unexpectedly, we found that paramagnetic Au25(SR)180 undergoes spontaneous bimolecular fusion to form another benchmark gold nanocluster, Au38(SR)24. We tested reaction with series Au25 clusters. was confirmed and characterized UV–vis absorption...

Thiolate-protected metal clusters are materials of ever-growing importance in fundamental and applied research. Knowledge their single-crystal X-ray structures has been instrumental to enable advanced molecular understanding intriguing properties. So far, however, a general, reliable, chemically clean approach prepare single crystals suitable for accurate crystallographic analysis was missing. Here we show that thiolate-protected can be grown large quantity very high quality by...

Several research groups have observed magnetism in monolayer-protected gold cluster samples, but the results were often contradictory, and thus, a clear understanding of this phenomenon is still missing. We used Au25(SCH2CH2Ph)180, which paramagnetic that can be prepared with atomic precision whose structure known precisely. Previous magnetometry studies only detected paramagnetism. samples representing range crystallographic orders studied their magnetic behaviors using electron resonance...

The dissociative reduction of a series symmetrical (RSSR, R = H, Me, t-Bu, Ph) and unsymmetrical disulfides (RSSR', R' Me Ph, t-Bu) was studied theoretically, by MO ab initio calculations and, for five them, also experimentally, convolution voltammetry in N,N-dimethylformamide. is but proceeds stepwise mechanism entailing the formation radical anion species. electrochemical data led to estimated large intrinsic barriers, agreement with an unusually structural modification undergone disulfide...

The rate constant of intramolecular electron transfer through oligopeptides based on the α-aminoisobutyric acid residue was determined as a function peptide length and found to depend weakly donor−acceptor separation. By measuring electron-transfer activation energy estimating gap between donor bridge, we were able discard hopping mechanism.

The electron transfer (ET) to a series of para-substituted diaryl disulfides, having the general formula (X−C6H4S−)2, has been studied. X groups were selected as have comprehensive variation substituent effect, being = NH2, MeO, H, F, Cl, CO2Et, CN, and NO2. reduction was carried out experimentally, using N,N-dimethylformamide solvent, by molecular orbital (MO) ab initio calculations. ET studied heterogeneously, voltammetric convolution analysis, homogeneously, electrogenerated radical...

The first investigation on the distance dependence of a dissociative electron transfer process across peptide bridges is reported. This study was carried out by using series donor-peptide-acceptor systems in which donor phthalimido moiety, are provided alpha-aminoisobutyric acid (Aib) homooligomers, and acceptor peroxide functional group. intramolecular from electrogenerated radical anion to studied comparison with thermodynamic kinetic information obtained models donor. rate constants were...

The electron transfer (ET) properties of Au38 clusters protected by a phenylethanethiolate monolayer, Au38(SR)24, were studied in N,N-dimethylformamide and dichloromethane. kinetic parameters the first oxidation steps (+1/0 +2/+1) reduction step (0/−1) obtained electrochemical methods. anion electrogenerated from Au38(SR)24 was employed homogeneous redox catalysis experiments, using diphenyl disulfide benzyl bromide as acceptors. Both heterogeneous analyses pointed to fast ET behavior...

Au25L18 (L = S(CH2)2Ph) clusters were prepared and characterized. The resulting monodisperse reacted with bis(pentafluorobenzoyl) peroxide in dichloromethane to form Au25L18+ quantitatively. kinetics thermodynamics of the corresponding electron transfer (ET) reactions characterized via electrochemistry thermochemical calculations. was used homogeneous redox catalysis experiments a series sym-substituted benzoyl peroxides, including above peroxide, bis(para-cyanobenzoyl) dibenzoyl...

The electrochemical reduction of tert-butyl p-cyanoperbenzoate in DMF leads to the cleavage oxygen−oxygen bond. A subsequent reaction yielding p-cyanobenzoate could be avoided by addition a mild acid, with result that main peak was affected only kinetics electron transfer bond fragmentation process. Unusual features heterogeneous mechanism were evidenced conventional voltammetric criteria, which pointed nonlinear potential dependence coefficient α. fine details obtained convolution analysis...

Singlet oxygen,

Abstract Atomically precise ligand‐protected nanoclusters (NCs) constitute an important class of compounds that exhibit well‐defined structures and, when sufficiently small, evident molecular properties. NCs provide versatile building blocks to fabricate hierarchical superstructures. The assembly indeed offers opportunities devise new materials with given and able carry out specific functions. In this Concept article, we highlight the possibilities offered by in which physicochemical...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTEvidence for Large Inner Reorganization Energies in the Reduction of Diaryl Disulfides: Toward a Mechanistic Link between Concerted and Stepwise Dissociative Electron Transfers?Kim Daasbjerg, Henrik Jensen, Rois Benassi, Ferdinando Taddei, Sabrina Antonello, Armando Gennaro, Flavio MaranView Author Information Department Chemistry, University Aarhus DK-8000 C, Denmark Dipartimento di Chimica, Università Modena via Campi 183, 41100 Modena,...