ABSTRACT
Atomically precise superatomic copper nanoclusters (Cu NCs) have been the subject of immense interest for their intriguing structures and diverse properties; nonetheless, the variable oxidation state of copper ions and complex solvation effects in wet synthesis systems pose significant challenges for comprehending their synthesis and crystallization mechanism. Herein, we present a solvent-mediated approach for the synthesis of two Cu NCs, namely, superatomic Cu26 and pure-Cu(I) Cu16. They initially formed as a hetero-phase and then separated as a homo-phase via modulating binary solvent composition. In situ UV/vis absorption and electrospray ionization mass spectra revealed that the solvent-mediated assembly was determined to be the underlying mechanism of hetero/homo-phase crystallization. Cu26 is a 2-electron superatom with a kernel-shell structure that includes a [Cu20Se12]4- shell and [Cu6]4+ kernel, containing two 1S jellium electrons. Conversely, Cu16 is a pure-Cu(I) Cu/Se nanocluster that features a [Cu16Se6]4+ core protected by extra dimercaptomaleonitrile ligands. Remarkably, Cu26 exhibits unique near-infrared phosphorescence (NIR PH) at 933 nm due to the presence of a superatomic kernel-related charge transfer state (3MM(Cu)CT). Overall, this work not only showcases the hetero/homo-phase crystallization of Cu NCs driven by a solvent-mediated assembly mechanism but also enables the rare occurrence of NIR PH within the 2-electron copper superatom family.
ABSTRACT
The functionalization of polyoxovanadate clusters is promising but of great challenge due to the versatile coordination geometry and oxidation state of vanadium. Here, two unprecedented silsesquioxane ligand-protected "fully reduced" polyoxovanadate clusters were fabricated via a facial solvothermal methodology. The initial mixture of the two polyoxovanadate clusters with different colors and morphologies (green plate V14 and blue block V6) was successfully separated as pure phases by meticulously controlling the assembly conditions. Therein, the V14 cluster is the highest-nuclearity V-silsesquioxane cluster to date. Moreover, the transformation from a dimeric silsesquioxane ligand-protected V14 cluster to a cyclic hexameric silsesquioxane ligand-protected V6 cluster was also achieved, and the possible mechanism termed "ligand-condensation-involved dissociation reassembly" was proposed to explain this intricate conversion process. In addition, the robust V6 cluster was served as a heterogeneous catalyst for the synthesis of important heterocyclic compounds, quinazolinones, starting from 2-aminobenzamide and aldehydes. The V6 cluster exhibits high activity and selectivity to access pure quinazolinones under mild conditions, where the high selectivity was attributed to the confinement effect of the macrocyclic silsesquioxane ligand constraining the molecular freedom of the reaction species. The stability and recyclability as well as the tolerance of a wide scope of aldehyde substrates endow the V6 cluster with a superior performance and appreciable potential in catalytic applications.
ABSTRACT
Herein, two atomically precise silver nanoclusters, Ag54 and Ag33, directed by inner anion templates (CrO4 2- and/or Cl-), are initially isolated as a mixed phase from identical reactants across a wide temperature range (20-80 °C). Interestingly, fine-tuning the reaction temperature can realize pure phase synthesis of the two nanoclusters; that is, a metastable Ag54 is kinetically formed at a low temperature (20 °C), whereas such a system is steered towards a thermodynamically stable Ag33 at a relatively high temperature (80 °C). Electrospray ionization mass spectrometry illustrates that the stability of Ag33 is superior to that of Ag54, which is further supported by density functional theory calculations. Importantly, the difference in structural stability can influence the pathway of 1,4-bis(pyrid-4-yl)benzene induced transformation reaction starting from Ag54 and Ag33. The former undergoes a dramatic breakage-reorganization process to form an Ag31 dimer (Ag31), while the same product can be also achieved from the latter following a noninvasive ligand exchange process. Both the Ag54 and Ag33 have the potential for further remote laser ignition applications. This work not only demonstrates how temperature controls the isolation of a specific phase, but also sheds light on the structural transformation pathway of nanoclusters with different stability.
ABSTRACT
Although the C-H···O interaction is an essential component in determining the molecular packing in solids and the properties in supramolecular chemistry, it presents a significant challenge when trying to use it in the crystal engineering of complex metallosupramolecules, even though it is a relatively weak supramolecular force. The first pair of high-nuclearity silver-cluster-based one-dimensional (1D) polymorphs built from supramolecular synthon [W10O32@Ag48(CyS)24(NO3)16]·4NO3 (Cy = cyclohexyl) bridged by four grouped inorganic NO3- ligands is initially synthesized as a mixed phase and further individually crystallized as a pure phase by virtue of tuning intermolecular C-H···O interaction through altering the composition ratio of ternary solvent system. Increasing highly polar and hydrogen-bonding methanol strengthens the solvation effect reflected by the change of coordination orientation of surface NO3- ligands, which dominates the packing of the 1D chains in the crystal lattice, resulting in the crystallization of polymorphs from tetragonal to monoclinic. The two crystalline forms can also be reversibly transformed to each other in an appropriate solvent system. Correspondingly, the two polymorphs display distinct temperature-dependent photoluminescence behaviors, which are ascribed to the variation of noncovalent interchain C-H···O interactions along with the temperature. More importantly, benefiting from the suppression of fluorescence, both polymorphs offer excellent photothermal conversion properties which were further applied to remote-controlled laser ignition. These findings may open more avenues for the application of solvent-mediated intermolecular interaction in controlling the molecule arrangement as well as the optical properties.
ABSTRACT
Structural transformation of metal nanoclusters (NCs) is of great ongoing interest regarding their synthesis, stability, and reactivity. Although sporadic examples of cluster transformations have been reported, neither the underlying transformation mechanism nor the intermediates are unambiguous. Herein, we have synthesized a flexible 54-nuclei silver cluster (Ag54) by combining soft (tBuC≡C-) and hard (nPrCOO-) ligands. The existence of weakly coordinated nPrCOO- enhances the reactivity of Ag54, thus facilitating the dicarboxylic acid to induce structural transformation. X-ray structural analyses reveal that Ag54 transforms to Ag28 cluster-based 2D networks (Ag28a and Ag28b) induced by H2suc (succinic acid) and H2glu (glutaric acid), whereas with H2pda (2,2'-(1,2-phenylene)diacetic acid), a discrete Ag28 cluster (Ag28c) is isolated. The key intermediate Ag17 that emerges during the self-dissociation of Ag54 was isolated by using cryogenic recrystallization and characterized by X-ray crystallography. The "tandem transformation" mechanism for the structure evolution from Ag54 to Ag28a is established by time-dependent electrospray ionization mass spectrometry (ESI-MS) and UV-vis spectroscopy. In addition, the catalytic activity in the 4-nitrophenol reduction follows the sequence Ag28c > Ag28b > Ag28a > Ag54 due to more bare silver sites on the surface of the Ag28 cluster unit. Our findings not only open new avenues to the synthesis of silver NCs but also shed light on a better understanding of the structural transformation mechanism from one cluster to another or cluster-based metal-organic networks induced by dicarboxylates.
ABSTRACT
Silver nanoclusters have emerged as promising candidates for optoelectronic applications, but their room-temperature photoluminescence quantum yield (PLQY) is far from ideal to access cutting-edge device performance. Herein, two supertetrahedral silver nanoclusters with high PLQY in non-degassed solution at room temperature were constructed by interiorly supporting the core with multiple VO43- and E2- anions as structure-directing agents and exteriorly protecting the core with a rigid ligand shell of PhC≡C- and Ph2PE2- (E = S, Ag64-S; E = Se, Ag64-Se). Both clusters have similar outer Ag58 tetrahedral cages and [Ag6E4@(VO4)4] cores, forming a pair of comparable clusters to decrypt the origin of such a high PLQY, particularly in Ag64-S, where the PLQY reached up to 97%. The stronger suppression effect of inner sulfides for nonradiative decay is critical to boost the PLQY to near unity. Transient absorption spectroscopy is employed to confirm the phosphorescence nature. The quadruple-capping assembly mechanism involving Ag7 secondary building units on a Ag36 truncated tetrahedron was also established by collision-induced dissociation studies. This work not only provides a strategy of core engineering for the controlled syntheses of silver nanoclusters with high PLQY but also deciphers the origin of a near-unity PLQY, which lays a foundation for fabricating highly phosphorescent silver nanoclusters in the future.
ABSTRACT
Structural modulation of core-shell silver nanoclusters from the inside is a huge challenge but of great importance in their syntheses. Herein, two silver nanoclusters [Ag3 S9 @Ag42 ] (SD/Ag45b) and [Ag9 S9 @Ag42 ] (SD/Ag51a) are isolated in the presence of different kinds of sulfonic acids. Uniquely, SD/Ag45b and SD/Ag51a show typical core-shell structures with the similar Ag42 shell but different cores. The outer shell of 42 silver atoms comprises two Ag3 trigons at two poles encircled by three equatorial distorted square cupolas (J4 , Ag12 ). The core in SD/Ag45b is a silver trigon ligated by nine S2- ions (Ag3 S9 ), while a tricapped triangular prismatic Ag9 also ligated by the same amount of S2- ions (Ag9 S9 ) is observed in the inner core of SD/Ag51a. The electrospray ionization mass spectrometry (ESI-MS) indicates that the introduction of p-toluenesulfonic acid can realize the transformation from SD/Ag45b to Ag51 . SD/Ag45b and SD/Ag51a show inverse luminescence thermochromic behaviors in the near-infrared (NIR) region, mainly dictated by the inner silver cores. This work not only realizes the synthesis of new silver nanoclusters by core modulation but also provides a prototype to get molecular-level insight into the correlation between structure and luminescence thermochromism.
Subject(s)
Luminescence , Silver , Silver/chemistryABSTRACT
Stepwise assembly starting from a preassembled metalloligand is a promising approach to obtain otherwise unattainable silver nanoclusters, but hard to be intrinsically identified due to the lack of convincing evidence to justify such a process. Herein, hexagonal and rectangular Ag18 nanoclusters are constructed from the [Mo2 O5 (PTC4A)2 ]6- (H4 PTC4A=p-phenyl-thiacalix[4]arene) metalloligand through stepwise assembly. The formation of the metalloligand is confirmed by electrospray ionization mass spectrometry, then assembled with silver ions to form two geometrically different Ag18 nanoclusters in different solvents. The cyclization from the metalloligand to [(Mo2 O5 PTC4A)6 ]12- can be realized without alcohols and otherwise blocked by them. The installation of this metalloligand not only provides comprehensive understanding of how the solvents regulate the silver nanocluster structures, but also brings new insights for the controllable ligand metallization and subsequent condensation.
ABSTRACT
Kinetically stable and long-lived intermediates are crucial in monitoring the progress and understanding of supramolecular self-assembly of diverse aggregated structures with collective functions. Herein, the complex dynamics of an atomically precise CuI nanocluster [Cu8 (t BuC6 H4 S)8 (PPh3 )4 ] (Cu8a) is systematically investigated. Remarkably, by monitoring the aggregation-induced emission (AIE) and electron microscopy of the kinetically stable intermediates in real time, the directed self-assembly (DSA) process of Cu8a is deduced. The polymorphism and different emission properties of Cu NCs aggregates were successfully captured, allowing the structure-optical property relationship to be established. More importantly, the utilization of a mathematical "permutation and combination" ideology by introducing a heterogeneous luminescent agent of a carbon dot (CD) to Cu8a aggregates enriches the "visualization" fluorescence window, which offers great potential in real time application for optical sensing of materials.
ABSTRACT
A highly robust heterometallic CoIILaIII2-organic framework (NUC-19) is synthesized and features 1D rectangle-like channels with a window size of 3.4 × 6.3 Å2 and a carboxyl-group-modified inner surface. NUC-19 exhibits significantly differential uptake for C2H2, C2H4, and CH4, and the ideal adsorbed solution theory selectivities of C2H2/C2H4 (1:99, v/v) and C2H2/CH4 (50:50, v/v) at room temperature can reach up to 4.0 and 79.7, respectively. Fixed-bed dynamic breakthrough experiments under simulated industrial conditions indicate that NUC-19 could efficiently trap C2H2 from mixed gases of C2H2/CH4 and C2H2/C2H4.
ABSTRACT
Layering AgNO3 in alcohol onto octavinylsilsesquioxane (OVS) in CHCl3 results in a one-dimensional coordination polymer, {Ag4(NO3)4(OVS)·solvents}n (SD/Ag4a-d), consisting of unprecedented flat weakly bonded Ag4(NO3)4 alternating with the firmly covalent OVS through AgI-πCâC bonds. The preferential assembling medium for SD/Ag4a is proven to be alcohols, where a 4:1 silver-OVS adduct is detected by electrospray ionization mass spectrometry. The present outcomes may assist our knowledge of particular interactions for supramolecular architectures of a polynuclear silver system built from OVS containing eight pendent olefin tails.
ABSTRACT
The mild reaction of the preorganized silsesquioxane precursor with Mn(II) acetate under ambient conditions results in a mixed-valent {MnII6MnIII4} nanocage (SD/Mn10) which is protected by both acyclic trimer [Si3] and cyclic tetramer [Si4]. Serendipitous capture of atmospheric CO2 as a µ5-carbonate anion placed at the center supports the formation of the cluster. The magnetic analysis reveals the strong antiferromagnetic interactions between Mn ions. Moreover, the drop-casting film of SD/Mn10 shows photoelectric activity indicating its great potential as a semiconductor for photoelectric conversion applications.
ABSTRACT
Luminescent metal-organic frameworks (LMOFs) as sensors showing highly efficient detection toward toxic heavy-metal ions are in high demand for human health and environmental protection. A novel nanocage-based N-rich LMOF (LCU-103) has been constructed and characterized. It is a 2-fold interpenetrating structure built from N-rich {Zn6(dttz)4} nanocages extended by N-donor ligand Hdpa [H3dttz = 4,5-di(1H-tetrazol-5-yl)-2H-1,2,3-triazole; Hdpa = 4,4'-dipyridylamine]. Notably, LCU-103 contains abundant N functional sites anchoring on both the windows of nanocages and the inner channels of the framework that can interact with metal ions and then recognize them. As a result, it can serve as a luminescent sensing material for detecting trace amounts of Fe3+ and Cu2+ ions with low limits of detection (LODs) of 1.45 and 1.66 µM, respectively, through a luminescent quenching mechanism. Meanwhile, LCU-103 as a LMOF sensor exhibits several advantages such as high sensitivity, appropriate selectivity (for Fe3+ in H2O), recycling stability, and fast response times in N,N-dimethylformamide. Moreover, LCU-103 also displays good luminescent quenching activity toward Fe3+ in H2O and a simulated 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid biological system with low LODs of 1.51 and 1.52 µM, respectively. LCU-103 test papers were further prepared to offer easy and real-time detection of Fe3+ and Cu2+ ions. Importantly, when density functional theory calculations and multiple experimental evidence, including X-ray photoelectron spectroscopy, UV-vis absorption, luminescence decay lifetimes, and quantum efficiencies, are combined, a preferred N-donor site and possible weak interaction sensing mechanism is also proposed to elucidate the quenching effect.
ABSTRACT
It is well known that structure determines property, but obtaining a pair of silver nanoclusters with comparable structures to understand the structure-property relationship is a very challenging task. A new 60-nuclei silver nanocluster (SD/Ag60a) protected by a mixed-ligand shell of tBuS- and o-CH3OPhCOO- was obtained and characterized. Single crystal x-ray diffraction reveals that SD/Ag60a has an identical metal nuclearity and core-shell structural type to SD/Ag1 previously reported by our group, whereas the compositions of the core and shell have undergone a rearrangement from an Ag12 cuboctahedron core and an Ag48 rhombicuboctahedron shell in SD/Ag1 to an Ag14 rhombic dodecahedron core and an oval Ag46 shell in SD/Ag60a. The core enlargement from Ag12 to Ag14 originates from the replacement of two S2- in Ag12S15 by two Ag+, which gives a new Ag14S13 core. This result indicates that the metal frameworks of silver nanoclusters have some extent flexibility despite the same nuclearity, which can be influenced by ligands, solvents, anion templates, and others in the embryonic stage of the assembly. Interestingly, different core-shell architectures of Ag60 nanoclusters also significantly endow the different optical absorption bands, photocurrent-generating properties, and luminesecent behaviors. This work not only realizes the regulation of the core-shell structure of silver nanoclusters with the same nuclearity but also provides a comparable model for investigating the relationship of structure-photoelectric properties.
ABSTRACT
Two anti-thymocyte globulin (ATG) forms are used in graft-versus-host disease (GVHD) prophylaxis during haploidentical hematopoietic stem cell transplantations (haplo-HSCTs): ATG-thymoglobulin (ATG-T) and ATG-fresenious (ATG-F). However, comparable dosages for haplo-HSCT remain unclear. We compared and evaluated the effects of ATG-T (7.5 mg/kg) or ATG-F (20 mg/kg) dosages in a relatively homogenous population in haplotype HSCT settings. Patients administered ATG-T 7.5 mg/kg (n = 81) or ATG-F 20 mg/kg (n = 35) as part of GVHD prophylaxis during haplo-HSCT were enrolled. Incidence and severity of GVHD, Epstein-Barr virus (EBV) infection, and immune cell recovery were compared using the Mann-Whitney U rank test and chi-square test. Cumulative incidences of GVHD, EBV infection and its subgroups, and relapse mortality were computed; overall survival (OS) was analyzed using the Kaplan-Meier method, with the log-rank test used for univariate comparison. Risk factors for OS were analyzed by the Cox proportional hazards model. Incidence and cumulative incidence of all grades of acute GVHD and subgroups were comparable in both groups (all p > 0.05); however, cumulative incidence of any grade and limited chronic GVHD was significantly higher in the ATG-T group (p = 0.002, p = 0.007, respectively). Cumulative incidences of EBV infections, EBV-DNAemia, and EBV-related diseases were similar; relapse mortality and OS rates were comparable between both groups (all p > 0.05). ATG-T dosage (7.5 mg/kg) appeared comparable to ATG-F dosage (20 mg/kg) for haplo-HSCT. Currently approved ATG-T and ATG-F doses appear efficient to balance the risk-benefit ratio of GVHD, OS, relapse mortality, and EBV infection in haplo-HSCT.
Subject(s)
Antilymphocyte Serum/administration & dosage , Epstein-Barr Virus Infections/drug therapy , Graft vs Host Disease/drug therapy , Hematologic Neoplasms/drug therapy , Hematopoietic Stem Cell Transplantation/trends , Adolescent , Adult , Child , Child, Preschool , Epstein-Barr Virus Infections/epidemiology , Female , Follow-Up Studies , Graft vs Host Disease/epidemiology , Haploidy , Hematologic Neoplasms/epidemiology , Hematopoietic Stem Cell Transplantation/adverse effects , Humans , Immunosuppressive Agents/administration & dosage , Male , Middle Aged , Retrospective Studies , Young AdultABSTRACT
Human leukocyte antigen (HLA)-haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is an effective alternative to HLA-matched transplantation. However, Epstein-Barr virus (EBV) infection causes morbidity and mortality in patients undergoing haplo-HSCT. Here, we retrospectively evaluated the incidence and risk factors of EBV-DNAemia and EBV-associated diseases in 131 patients who underwent haplo-HSCT. Patients were classified into the no EBV infection groups, EBV-DNAemia group and EBV-associated disease group. Cumulative incidences of acute graft-vs-host disease, EBV infections, overall survival (OS), and relapse were analyzed. The cumulative incidences of EBV-DNAemia and EBV-associated disease were 26.9% and 33.3%, respectively. In multivariate analysis, cytomegalovirus (CMV)-DNAemia was confirmed as an independent risk factor associated with EBV-DNAemia and EBV-associated disease. Patients with EBV-associated disease had higher transplant-related mortality (TRM) rates and lower OS rates, but similar relapse rates. Overall, these findings demonstrated the cumulative incidences of EBV-DNAemia and EBV-associated disease and identified correlations of EBV infection with TRM, relapse, and OS. Additionally, CMV-DNAemia was a risk factor for EBV-DNAemia and EBV-associated disease.
Subject(s)
Epstein-Barr Virus Infections , Hematopoietic Stem Cell Transplantation , Epstein-Barr Virus Infections/epidemiology , Epstein-Barr Virus Infections/etiology , Hematopoietic Stem Cell Transplantation/adverse effects , Herpesvirus 4, Human/genetics , Humans , Incidence , Retrospective Studies , Risk FactorsABSTRACT
CGD is a rare primary immunodeficiency with high mortality rates when treated conventionally, especially for the X-chromosome-linked form. HSCT is the only curative therapy for CGD; however, haploidentical transplantation in CGD is rare. Here, we report a case of X-linked CGD treated successfully by haploidentical HSCT. The patient showed a positive result with full donor chimerism, good quality of life, and the absence of recurrent infectious diseases at follow-up (68 months). Thus, haploidentical HSCT may serve as an acceptable treatment approach for patients who have CGD, but no HLA-matched related or unrelated donor.
Subject(s)
Granulomatous Disease, Chronic/therapy , Hematopoietic Stem Cell Transplantation , Adolescent , Busulfan/administration & dosage , Chromosomes, Human, X , Cyclophosphamide/administration & dosage , Humans , Male , Quality of Life , Transplantation ConditioningABSTRACT
Precise control over the shape and size of metal nanoclusters through anion template-driven self-assembly is one of the key scientific goals in the nanocluster community, however, it is still not understood comprehensively. In this work, we report the controllable synthesis and atomically precise structures of silver nanowheels Ag37 and Ag46, using homo (Cl- ions) and heteroanion (Cl- and CrO4 2- ions) template strategies, along with macrocyclic p-phenyl-thiacalix[4]arene and small iPrS- ligands. Structural analyses revealed that in Ag37, Cl- ions serve as both local and global templates, whereas CrO4 2- ions function as local and Cl- ions as global templates in Ag46, resulting in a pentagonal nanowheel (Ag37) and a hexagonal (Ag46) nanowheel. The larger ionic size and more negative charges of CrO4 2- ions than Cl- ions offer more coordination sites for the silver atoms and are believed to be the key factors that drive the nanowheel core to expand significantly. Also, by taking advantage of the deep cavity of thiacalix[4]arene with an extended phenyl group, Ag46 has been used as a host material for dye adsorption depending on the charge and size of organic dyes. The successful use of heteroanions to control the expansion of well-defined silver nanowheels fills the knowledge gap in understanding the directing role of heteroanions in dictating the shape and size of nanoclusters at the atomic level.
ABSTRACT
Intrinsic dual-emission (DE) of gold nanoclusters in the near-infrared (NIR) are fascinating for fundamental importance and practical applications, but their synthesis remains a formidable challenge and sophisticated excited-state processes make elucidating DE mechanisms much more arduous. Here, we report an all-alkynyl-protected gold nanocluster, Au20, showing a prolate Au12 tri-octahedral kernel surrounded by two Au2(CZ-PrA)3 dimers, four Au(CZ-PrA)2 monomers, and two CZ-PrA- bridges. Au20 exhibits distinguished photophysical properties including NIR DE at 820 and 940 nm, microsecond radiative relaxation, and 6.26% photoluminescent quantum yield at ambient environment in nondegassed solution. Combining systematic studies on steady/transient spectroscopy and theoretical calculation, we identified two triplet charge transfer (CT) states, ligand-to-kernel and kernel-based CT states as DE origins. Furthermore, this NIR DE exhibits highly independent and sensitive response to surrounding environments, which well coincide with its mechanism. This work not only provides a substantial structure model to understand a distinctive DE mechanism but also motivates the further development of NIR DE materials.
ABSTRACT
The assembly of cluster-based π-stacked porous supramolecular frameworks presents daunting challenges, including the design of suitable cluster building units, control of the sufficient C-H···π interactions, trade-off between structural dynamics and stability as well as understanding the resulting collective properties. Herein, we report a cluster-based C-H···π interaction-stacked porous supramolecular framework, namely, Cu12a-π, consisting of Cu12 nanocluster as a 6-connected node, which is further propagated to a dynamic porous supramolecular frameworks via dense intralayer C-H···π interactions, yielding permanent porosity. In addition, Cu12a-π can be transformed into cluster-based nonporous adaptive crystals (Cu12b-NACs) via ligand-exchange following a dissociation-reassembly mechanism. Moreover, Cu12a-π can efficiently remove 97.2% of iodine from saturated iodine aqueous solutions with a high uptake capacity of 2.96 g·g-1. These prospective results positioned at cluster-based porous supramolecular framework and enlighten follow-up researchers to design and synthesize such materials with better performance.