Figure - available from: Small
This content is subject to copyright. Terms and conditions apply.
![A) 3D and B) 2D views of [Na4Ag44(p‐MBA)30] NC superlattice structures. A view of a single NC is provided in the inset (i). C) The stacking of NC layers in the assembly is depicted in the XY three‐layer projection. D) The interlayer hydrogen bonding between neighboring NCs, involving triply bundled ligands are shown. An enlargement of the hydrogen‐bonded region is given in inset (ii), showing two hydrogen bonds between each pair of interfacing ligands. Reproduced with permission.[²¹⁷] Copyright 2014, Springer Nature. E) Synthetic route for [Au102(p‐MBA)44] NCs and their internal structure extracted from the solid‐state structure. F) HR‐TEM image of 2D colloidal crystal fabricated from [Au102(p‐MBA)44] NCs with facetted edges showing the stacked NC layers. Reproduced with permission.[²¹⁹] Copyright 2016, Wiley‐VCH.](profile/Nonappa-2/publication/348745244/figure/fig1/AS:11431281255407843@1719420153027/A-3D-and-B-2D-views-of-Na4Ag44p-MBA30-NC-superlattice-structures-A-view-of-a.png)
A) 3D and B) 2D views of [Na4Ag44(p‐MBA)30] NC superlattice structures. A view of a single NC is provided in the inset (i). C) The stacking of NC layers in the assembly is depicted in the XY three‐layer projection. D) The interlayer hydrogen bonding between neighboring NCs, involving triply bundled ligands are shown. An enlargement of the hydrogen‐bonded region is given in inset (ii), showing two hydrogen bonds between each pair of interfacing ligands. Reproduced with permission.[²¹⁷] Copyright 2014, Springer Nature. E) Synthetic route for [Au102(p‐MBA)44] NCs and their internal structure extracted from the solid‐state structure. F) HR‐TEM image of 2D colloidal crystal fabricated from [Au102(p‐MBA)44] NCs with facetted edges showing the stacked NC layers. Reproduced with permission.[²¹⁹] Copyright 2016, Wiley‐VCH.
Source publication
![A) 3D and B) 2D views of [Na4Ag44(p‐MBA)30] NC superlattice structures....](profile/Nonappa-2/publication/348745244/figure/fig1/AS:11431281255407843@1719420153027/A-3D-and-B-2D-views-of-Na4Ag44p-MBA30-NC-superlattice-structures-A-view-of-a_Q320.jpg)
![A) Schematic illustration showing the evolution of [Cu12(DT)8Ac4] NC...](profile/Nonappa-2/publication/348745244/figure/fig4/AS:11431281255360827@1719420153881/A-Schematic-illustration-showing-the-evolution-of-Cu12DT8Ac4-NC-self-assembly_Q320.jpg)
![A) Overall structure of ligands on the surface of [Au246(p‐MBT)80] NCs....](profile/Nonappa-2/publication/348745244/figure/fig5/AS:11431281255360828@1719420154234/A-Overall-structure-of-ligands-on-the-surface-of-Au246p-MBT80-NCs-B-Rotational-and_Q320.jpg)
Ligand protected noble metal nanoparticles are excellent building blocks for colloidal self‐assembly. Metal nanoparticle self‐assembly offers routes for a wide range of multifunctional nanomaterials with enhanced optoelectronic properties. The emergence of atomically precise monolayer thiol‐protected noble metal nanoclusters has overcome numerous c...
Citations
... One of the most compelling aspects of gold thiolate clusters is their ability to form self-assembled nanostructures [14,15]. The amphiphilic nature of tailored ligands enables controlled aggregation and hierarchical organization, which can significantly alter their photophysical behavior [16,17]. Such properties have fueled interest in their use for designing stimuli-responsive nanomaterials with applications in biosensing, energy storage, and targeted drug delivery [18][19][20]. ...
... In addition to intracluster regulation, intercluster noncovalent interactions are conducive to improve the emission properties of nanoclusters [7][8][9]. For example, monothiolprotected copper nanoclusters contain C-H … B and B-H … B-H interactions in the solid state, resulting in tuneable phosphorescence [10]. ...
The synthesis of a novel bidentate ligand-protected copper nanocluster via a solid-state strategy is reported. Single-crystal X-ray diffraction analysis result reveals that the copper nanocluster features an octahedral core (Cu6) coordinated by six ligands. Noncovalent interactions (C-H…π and π…π) exist between the copper nanoclusters. The copper nanocluster displays luminescence even at 250 °C. The luminescence intensity is linearly correlated with temperature changes. The copper nanocluster can assemble into luminescent nanosheets whose emission is quenched by 4-nitrophenol. Spectroscopic analysis and theoretical calculations results demonstrate that the inner filter effect and electron transfer cause the above quenching effect. A probe based on luminescent nanosheets was constructed for β-galactosidase activity determination. The linearity range is 3.3–91.8 U·L⁻¹, and the limit of detection is 0.45 U·L⁻¹. This probe was also evaluated for determination of the β-galactosidase activity in human serum via spiking experiments. The recoveries ranged from 96.2% to 101.8%.
Graphical Abstract
... 52 Now, it is commonly accepted that in the highly ordered assembly of weak/nonemissive NCs, the compact structure deriving from the restricted movement of ligands and strengthened metallophilic interactions would improve the radiative energy relaxation channel via ligand-tometal charge transfer (LMCT) and/or ligand-to-metal−metal charge transfer (LMMCT) processes. 49 Especially for the latter electronic transition, LMMCT, closer distances between metals in NCs or the assembly play a significant role in the PL properties of materials. Strategies following the notion of "unity is strength" have thus emerged to engineer the supramolecular forces toward solid-state strong emission, which is key to light-emitting device fabrication and many other applications. ...
For nanochemistry, precise manipulation of nanoscale structures and the accompanying chemical properties at atomic precision is one of the greatest challenges today. The scientific community strives to develop and design customized nanomaterials, while molecular interactions often serve as key tools or probes for this atomically precise undertaking. In this Perspective, metal nanoclusters, especially gold nanoclusters, serve as a good platform for understanding such nanoscale interactions. These nanoclusters often have a core size of about 2 nm, a defined number of core metal atoms, and protecting ligands with known crystal structure. The atomically precise structure of metal nanoclusters allows us to discuss how the molecular interactions facilitate the systematic modification and functionalization of nanoclusters from their inner core, through the ligand shell, to the external assembly. Interestingly, the atomic packing structure of the nanocluster core can be affected by forces on the surface. After discussing the core structure, we examine various atomic-level strategies to enhance their photoluminescent quantum yield and improve nanoclusters’ catalytic performance. Beyond the single cluster level, various attractive or repulsive molecular interactions have been employed to engineer the self-assembly behavior and thus packing morphology of metal nanoclusters. The methodological and fundamental insights systemized in this review should be useful for customizing the cluster structure and assembly patterns at the atomic level.
... Generally, nanoclusters (NCs) have been employed for various applications by considering their quantum confinement, functionalization ability, and stability over chemicals and light [28,29]. Particularly, thiolated NCs exhibit outstanding features including optical chirality, fluorescence resonance energy transfer (FRET), and biocompatibility. ...
Among all the heavy metal ions, Lead (Pb2+) has become a serious threat to human health and the environment. It is vital to develop an accurate system to monitor the Pb2+ level. Fluorescent and colorimetric sensors are one such system to detect Pb2+ with high accuracy. Herein, we used thiolated gold nanoclusters (GNC) decorated paper spot arrays for the detection of Pb2+ through a simple colorimetric method. The prepared GNC and the developed complex were well-studied using various characterizations. The addition of Pb2+ to GNC results in a slight shift in the absorption spectra from 485 nm to 534 nm. Further, GNC showed a broad emission peak centered around 650 nm, and the addition of Pb2+ resulted in an enhancement in the peak intensity, due to cation-induced-aggregation-induced emission enhancement (AIEE). The HR-TEM analysis confirms the spherical shape of the prepared GNCs with an average size of 2.60 nm. Whereas, the addition of Pb2+ onto GNC leads to the formation of an aggregated structure of size 6.17 nm due to the formation of a chelation complex. The GNC showed a particle size of 2 nm with a zeta potential of -16.45 mV, whereas the Pb2+@GNC complex exhibited an increment in an average size to 96 nm having a zeta potential of -19.67 mV, substantially demonstrating the capturing of Pb2+ by GNC. Overall, spectroscopic and surface morphology studies indicated aggregated induced emission (AIE) phenomena between GNC and Pb2+. The selective detection of Pb2+ by GNC was observed by the appearance of salmon pink to mauves colour and was captured using a smartphone. The developed paper spot array can detect up to 10 ppm of Pb2+. Further, the developed probe showed a distinguishable color change for Pb2+ along with other cations of interest such as Hg2+, Mg2+, K+, Mn2+, and Fe2+. Therefore, the present paper spot array could detect Pb2+ even in the presence of other metal ions due to its evident distinguishability. The fabricated GNC-embedded paper spot array obeys the new REASSURED criteria proposed by the World Health Organization (WHO) and could be used for on-spot detection of Pb2+.
... The well-organized superstructures of metal nanoclusters have been highly attractive to be exploited as nano-, micro-, meso-and macro-scale materials with multifarious functionalities, [1][2][3][4][5][6][7][8] such as cluster-based nanomedicines, heterogeneous catalysts, and quantum devices. [9][10][11][12][13][14] The selfassembly of metal nanoclusters via tailoring ligand characteristics in terms of their functional groups, steric hindrances, and withdrawing/donor electron groups has been developed as a versatile approach to achieving highly ordered cluster-based assemblies with atomic precision. ...
... Nematic liquid crystals (NLC) possess orientational order properties. Their physical and chemical properties can be changed by the injection of various dopants [1,2]. Combining molecular and supramolecular ordering and mobility of LCs with unique properties of nanomaterials is the key to developing advanced functional materials for the next generations of electronic and optoelectronic devices [3]. ...
Background
Optical luminescence in a composite system with nematic LC 4-octyloxy-4’-cyanobuphenyl (8OCB) and semiconductor quantum dots CdSe/CdS and CdSe/CdS/ZnS has been synthesized by a water-organic method.
Methods
Composites has been investigated by means of polarizing microscopy, dynamic light scattering and by measurements of dielectric properties in the frequency range from 20 Hz to 5 MHz. The non-radiative excitation energy transfer from the liquid crystal molecules to the quantum dot in the LC-QD composite is detected by using the luminescence spectroscopy method.
Results
This effect as well as the shift of the luminescence band is owing to components intermolecular interaction.
Conclusion
The optimal concentration of QD in a composite which enhanced luminescence intensity was detected.
... In addition, nonradiative relaxation dynamics simulations presented that the most stable isomer possesses the longer recombination time than crystallized isomer, which is attributed to the synergistic effect of NAC and decoherence time. Our results could provide practical guidance for predicting the structure of thiolate-protected gold nanoclusters, and valuable insights into the application of gold nanoclusters in photovoltaic and optoelectronic devices due to their excellent properties such as the easy modulation of the electronic state and band gap [34,35]. ...
Understanding the excited state behavior of isomeric structures of thiolate-protected gold nanoclusters is still a challenging task. In this paper, based on grand unified model (GUM) and ring model for describing thiolate-protected gold nanoclusters, we have predicted four isomers of Au 24 (SR) 16 nanoclusters. Density functional theory calculations show that the total energy of one of the predicted isomers is 0.1 eV lower in energy than previously crystallized isomer. The nonradiative relaxation dynamics simulations of Au 24 (SH) 16 isomers are performed to reveal the effects of structural isomerism on relaxation process of the lowest energy states, in which that most of the low-excited states consist of core states. In addition, crystallized isomer possesses the shorter e–h recombination time, whereas the most stable isomer has the longer recombination time, which may be attributed to the synergistic effect of nonadiabatic coupling (NAC) and decoherence time. Our results could provide practical guidance to predict new gold nanoclusters for future experimental synthesis, and stimulate the exploration of atomic structures of same sized gold nanoclusters for photovoltaic and optoelectronic devices.
... [41] Another recent promising strategy to develop metal nanoclusters for theranostic application relies on the self-assembly of atomically precise NCs. [19,42] Indeed nanoclusters produced with atomic precision with enhanced stability, and diverse surface functionalities, render them attractive as platform for developing superstructures via the self-assembly process. The amplification of the photophysical properties in such hierarchical structures opens up a new route to design nanosystems with high molecular sensitivity and can find applications from multimodal imaging and biosensing to therapies. ...
Luminescent gold nanoclusters are rapidly gaining attention as efficient theranostic targets for imaging and therapeutics. Indeed, their ease of synthesis, their tunable optical properties and tumor targeting make them potential candidates for sensitive diagnosis and efficacious therapeutic applications. This concept highlights the key components for designing gold nanoclusters as efficient theranostics focusing on application in the field of oncology.
... Such a unique set of features in a nanoscale system has been rationalized as the result of the 'size quantization' of AuNC electronic band structure, giving rise to defined UV-visible absorption, fluorescence, and catalytic behavior 3 . Owing to these distinguished properties, AuNCs are turning promising in several high-end fields, including sensing, nanomedicine, energy conversion, and catalysis 4 , and are steadily emerging as valuable building blocks in material and crystal design [5][6][7][8] . AuNC monodisperse size and structural accuracy rapidly led to their successful crystallization and to the determination of the first high-resolution crystal structure for Au 102 (L) 44 , obtained in 2007 by Kornberg and colleagues 9 . ...
Crystallization of atomically precise nanoclusters is gaining increasing attention, due to the opportunity of elucidating both intracluster and intercluster packing modes, and exploiting the functionality of the resulting highly pure crystallized materials. Herein, we report the design and single-crystal X-ray structure of a superfluorinated 20 kDa gold nanocluster, with an Au25 core coated by a shell of multi-branched highly fluorinated thiols (SF27) resulting in almost 500 fluorine atoms, i.e., ([Au25(SF27)18]⁰). The cluster shows a switchable solubility in the fluorous phase. X-ray analysis and computational studies reveal the key role of both intracluster and intercluster F···F contacts in driving [Au25(SF27)18]⁰ crystal packing and stabilization, highlighting the ability of multi-branched fluorinated thiols to endow atomically precise nanoclusters with remarkable crystallogenic behavior.
... Nevertheless, owing to the high complexity and intrinsic heterogeneity of NPs, it is challenging to fully and precisely map out their surface structures at the molecular level [159][160][161]. However, thanks to the rapid development of various metal NCs [162][163][164][165][166][167][168][169][170][171][172][173][174][175][176][177][178][179], especially the recent breakthrough in structure determination of NHC-ligated ones, it has become possible to understand the surface chemistry of NHC-functionalized metal nanomaterials at the atomic level. ...
N-heterocyclic carbenes (NHCs) represent one of the most important organic ligands in coordination chemistry, and have been recently attracting increasing attention in nanoscience. This review aims to provide an overview on recent research advances on the use of NHCs as stabilizing agents and functionality modifiers for metal nanoparticles (NPs) and nanoclusters (NCs). The review begins with the general introduction of NHCs and the initial discovery of NHC ligation on metal NPs. With the development of several effective strategies to decorate metal NPs with NHCs, the research enthusiasm for NHC-stabilized metal NPs has been expanded. NHCs on heterogeneous metal nanocatalysts help to modify the electronic and steric properties of the catalysts and thus improve their catalytic performances including reactivity, selectivity, stability and recyclability. For example, NHC-ligated gold NPs has been demonstrated to possess remarkably enhanced stability that cannot be achieved by other ligand systems. Moreover, significant progress has been made in the synthesis of atomically precise NHC-stabilized metal NCs and their crystallographic structure analysis, providing the unprecedented opportunity in understanding the carbene-metal interface at the atomic level. At the end of the review, personal perspectives on the further development of this embryonic while promising field is discussed.
