Abstract Homology is well known in organic chemistry; however, it has not yet been reported in nanochemistry. Herein, we introduce the concept of kernel homology to describe the phenomenon of metal nanoclusters sharing the same “functional group” in kernels with some similar properties. To illustrate this point, we synthesized two novel gold nanoclusters, Au 44 (TBBT) 26 and Au 48 (TBBT) 28 (TBBTH=4‐tert‐butylbenzenethiol), and solved their total structures by X‐ray crystallography, which reveals that they have the same Au 23 bi‐icosahedron capped with a similar bottom cap (Au 6 and Au 8 , respectively) in the kernels. The two novel gold nanoclusters, together with the existing Au 38 (PET) 24 nanocluster (PETH=phenylethanethiol), have the same “functional group”—Au 23 —in their kernels and have some similar properties (e.g., electrochemical properties); therefore, they are comparable to the homologues in organic chemistry.
We report a one-pot method for synthesizing atomically monodisperse Au25 nanoclusters stabilized with various functionalized thiols. This approach permits facile incorporation of specific functionality [such as –OH, –COOH, and atom transfer radical polymerization initiator –OC(O)C(CH3)2Br] into the protecting thiol ligand shell and provides convenient access to new types of Au25 nanoclusters inaccessible by the previous two-phase approach. Importantly, a distinct "size-focusing" process was identified in the growth process of Au25 nanoclusters in the one-pot reaction. This facile, one-pot synthesis of thiol-functionalized Au25 nanoclusters allows for the development of specific surface chemistry for practical applications of such nanoclusters, such as bioconjugation, sensing, and surface polymerization, and thus makes the approach and the Au25 nanoclusters of broad utility.
Crystallization-induced photoluminescence weakening was recently revealed in ultrasmall metal nanoparticles. However, the fundamentals of the phenomenon are not understood yet. By obtaining conformational isomer crystals of gold nanoclusters, we investigate crystallization-induced photoluminescence weakening and reveal that the shortening of interparticle distance decreases photoluminescence, which is further supported by high-pressure photoluminescence experiments. To interpret this, we propose a distance-dependent non-radiative transfer model of excitation electrons and support it with additional theoretical and experimental results. This model can also explain both aggregation-induced quenching and aggregation-induced emission phenomena. This work improves our understanding of aggregated-state photoluminescence, contributes to the concept of conformational isomerism in nanoclusters, and demonstrates the utility of high pressure studies in nanochemistry.
Among many outstanding findings associated with the quantum size effect, one of the most exciting is the discovery of the antigalvanic reaction (AGR), which is the opposite of the classic galvanic reaction (GR) that has a history of nearly 240 years. The GR, named after Italian scientist Luigi Galvani, involves the spontaneous reduction of a noble-metal cation by a less noble metal in solution driven by the difference in electrochemical potentials. Classic galvanic reduction has been widely applied and has recently received particular interest in nanoscience and nanotechnology. However, the opposite of GR, that is, reduction of metal ions by less reactive (or more noble) metals, has long been regarded as a virtual impossibility until the recent surprising findings regarding atomically precise ultrasmall metal nanoparticles (nanoclusters), which bridge the gap between metal atoms (complexes) and metal nanocrystals and provide opportunities for novel scientific findings due to their well-defined compositions and structures. The AGR is significant not only because it is the opposite of the classic galvanic theory but also because it opens extensive applications in a large range of fields, such as sensing and tuning the compositions, structures, and properties of nanostructures that are otherwise difficult to obtain. Starting with the proposal of the general AGR concept in 2012 by Wu, a new era began, in which AGR received widespread attention and was extensively studied. After years of effort, great advances have been achieved in the research on AGR, which will be reviewed below. In this Account, we first provide a short introduction to the AGR concept and then discuss the driving force of the AGR together with the effecting factors, including the ligand, particle size, solvent, metal ion precursor, and ion dose. Subsequently, the application of the AGR in engineering atomically precise alloy (bimetallic and trimetallic) and monometallic nanoclusters is described, and tuning the properties of the parent nanoclusters is also included. In particular, four alloying modes (namely, (i) addition, (ii) replacement, (iii) replacement and structural transformation, and (iv) nonreplacement and structural transformation) associated with the AGR are discussed. After that, the applications of the AGR in metal ion sensing and antioxidation are reviewed. Finally, future prospects are discussed, and some challenging issues are presented at the end of this Account. It is expected that this Account will stimulate more scientific and technological interests in the AGR, and exciting progress in the understanding and application of the AGR will be made in the coming years.
Nanoclusters. A silver-copper nanocluster with a golden ratio pentangle structure was prepared by Nan Yan, Zhikun Wu et al. in their Research Article (e202305604). The cluster shows promising photothermal conversion efficiency.
Abstract Atomically precise ~1‐nm Pt nanoparticles (nanoclusters, NCs) with ambient stability are important in fundamental research and exhibit diverse practical applications (catalysis, biomedicine, etc.). However, synthesizing such materials is challenging. Herein, by employing the mixture ligand protecting strategy, we successfully synthesized the largest organic‐ligand‐protected (~1‐nm) Pt 23 NCs precisely characterized with mass spectrometry and single‐crystal X‐ray diffraction analyses. Interestingly, natural population analysis and Bader charge calculation indicate an alternate, varying charge ‐layer distribution in the sandwich‐like Pt 23 NC kernel. Pt 23 NCs can catalyze the oxygen reduction reaction under acidic conditions without requiring calcination and other treatments, and the resulting specific and mass activities without further treatment are sevenfold and eightfold higher than those observed for commercial Pt/C catalysts, respectively. Density functional theory and d ‐band center calculations interpret the high activity. Furthermore, Pt 23 NCs exhibit a photothermal conversion efficiency of 68.4 % under 532‐nm laser irradiation and can be used at least for six cycles, thus demonstrating great potential for practical applications.
Structural isomerism in nanoparticles has recently emerged as a new topic and stimulated research interest because the atomic structures of ultrasmall nanoparticles may have great impact on their fundamental properties and applications. Here we report the correlation between ultrafast relaxation dynamics and atomic structures of two isomers of thiolate-protected Au38(SC2H4Ph)24. The bi-icosahedral Au38 (denoted as Au38Q) with a Au23 inner core in its atomic structure shows rapid decay (1.5 ps) followed by nanosecond relaxation to the ground state, whereas its structural isomer (Au38T) exhibits similar relaxation processes, but the rapid decay is accelerated by ∼50% (1.0 ps). The picosecond relaxations in both cases can be assigned to core–shell charge transfer or electronic rearrangement within the metal core. The acceleration of the fast decay in Au38T is ascribed to its unique core structure, which is made up of a mono-icosahedral Au13 capped by a Au12 tri-tetrahedron by sharing two atoms. Interestingly, coherent phonon emissions (25 cm–1 for Au38Q, 27 and 60 cm–1 for Au38T) are observed in both isomers with pumping in the NIR region. Our results illustrate for the first time the importance of atomic structures in the photophysics of same sized gold nanoclusters.
Dotierte Gold-Nanocluster Eine antigalvanische Reaktion ermöglicht die Synthese metalldotierter Gold-Nanocluster. In ihrer Zuschrift auf S. 4590 zeigen Y. Pei, Z. Wu und Mitarbeiter, dass Au20Cd4(SH)(SR)19 günstigere Eigenschaften aufweist als der Stammcluster.
Abstract Metal nanoclusters with precisely modulated structures at the nanoscale give us the opportunity to synthesize and investigate 1D nanomaterials at the atomic level. Herein, it realizes selective 1D growth of building block nanocluster “Au 13 Cd 2 ” into three structurally different nanoclusters: “hand‐in‐hand” (Au 13 Cd 2 ) 2 O, “head‐to‐head” Au 25 , and “shoulder‐to‐shoulder” Au 33 . Detailed studies further reveals the growth mechanism and the growth‐related tunable properties. This work provides new hints for the predictable structural transformation of nanoclusters and atomically precise construction of 1D nanomaterials.
It is significant but challenging to understand the property evolution of metal nanoclusters by orientated regulation of the electronic structure. Previous research has demonstrated that the optical properties of metal nanoclusters with anisotropic structures are greatly impacted by their longitudinal electronic structure. However, the manipulation of optical properties of metal nanoclusters by regulating their electronic structure through longitudinal dithiolate substitutions has not yet been reported. In this study, we first achieved the longitudinal single-dithiolate replacement of metal nanoclusters and obtained two novel nanoclusters: Au28(SPh-tBu)18(SCH2SCH2S) and Au28(SPh-tBu)18(SCH2CH2CH2S). Both experimental and theoretical results demonstrated the regulation of the electronic structure (dipole moment) in the z (longitudinal) and x directions, resulting in absorption redshift and photoluminescence (polarity) enhancement. These findings not only deepen the understanding of the property-electronic structure correlation of metal nanoclusters but also provide guidance for their subtle property tuning.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)