Thiolate Ligands Research Articles

All-Solution-Processed Perovskite Light-Emitting Diodes Based on a Thiol-Modified ZnO Electron-Transporting Layer.

All-solution-processed perovskite light-emitting diodes (LEDs) have the potential to be inexpensive and easily manufactured on a large scale without requiring vacuum thermal deposition of the emissive and charge transport layers. Zinc oxide (ZnO), which possesses superior optical and electronic properties, is commonly used in all-solution-processed optoelectronic devices. However, the polar solvent of ZnO inks can corrode the perovskite layer and cause severe photoluminescence quenching. In this work, we report the successful dispersion of ZnO nanoparticles in nonpolar n-octane by controlling the surface ligands from acetates to thiols. The nonpolar ink prevents the destruction of perovskite films. In addition, thiol ligands upshift the conduction band energy level, which also helps inhibit exciton quenching. Consequently, we demonstrate the fabrication of high-performance all-solution-processed green perovskite LEDs with a brightness of 21 000 cd/m2 and an external quantum efficiency of 6.36%. Our work provides a ZnO ink for fabricating efficient all-solution-processed perovskite LEDs.

Fully Reduced and Mixed-Valent Multi-Copper Aggregates Supported by Tetradentate Diamino Bis(thiolate) Ligands.

Tetradentate diamino bis(thiolate) ligands (l-N2S2(2-)) with saturated linkages between heteroatoms support fully reduced [(Cu(l-N2S2))2Cu2] complexes that bear relevance as an entry point toward molecules featuring the Cu2ICu2II(μ4-S) core composition of nitrous oxide reductase (N2OR). Tetracopper [(Cu(l-N2(SMe2)2))2Cu2] (l-N2(SMe2H)2 = N1,N2-bis(2-methyl-2-mercaptopropane)-N1,N2-dimethylethane-1,2-diamine) does not support clean S atom oxidative addition but undergoes Cl atom transfer from PhICl2 or Ph3CCl to afford [(Cu(l-N2(SMe2)2))3(CuCl)5], 14. When introduced to Cu(I) sources, the l-N2(SArH)2 ligand (l-N2(SArH)2 = N1,N2-bis(2-mercaptophenyl)-N1,N2-dimethylethane-1,2-diamine), made by a newly devised route from N1,N2-bis(2-fluorophenyl)-N1,N2-dimethylethane-1,2-diamine, ultimately yields the mixed-valent pentacopper [(Cu(l-N2SAr2))3Cu2] (19), which has 3-fold rotational symmetry (D3) around a Cu2 axis. The single CuII ion of 19 is ensconced within an equatorial l-N2(SAr)2(2-) ligand, as shown by 14N coupling in its EPR spectrum. Formation of 19 proceeds from an initial, fully reduced product, [(Cu(l-N2SAr2))3Cu2(Cu(MeCN))] (17), which is C2 symmetric and exceedingly air-sensitive. While unreactive toward chalcogen donors, 19 supports reversible reduction to the all-cuprous state; generation of [19]1- and treatment with S atom donors only return 19 because structural adjustments necessary for oxidative addition are noncompetitive with outer-sphere electron transfer. Oxidation of 19 is marked by intense darkening, consistent with greater mixed valency, and by dimerization in the crystalline state to a decacopper species ([20]2+) of S4 symmetry.

Characterizing the Semiconductor Nanocrystal Surface through Chemical Reactivity.

ConspectusMany desirable and undesirable properties of semiconductor nanocrystals (NCs) can be traced to the NC surface due to the large surface-to-volume ratio. Therefore, precise control of the NC surface is imperative to achieve NCs with the desired qualities. Ligand-specific reactivity and surface heterogeneity make it difficult to accurately control and tune the NC surface. Without a molecular-level appreciation of the NC surface chemistry, modulating the NC surface is impossible and the risk of introducing deleterious surface defects is imminent. To gain a more comprehensive understanding of the surface reactivity, we have utilized a variety of spectroscopic techniques and analytical methods in concert.This Account describes our use of robust characterization techniques and ligand exchange reactions in effort to establish a molecular-level understanding of NC surface reactivity. The utility of NCs in target applications such as catalysis and charge transfer hangs on precise tunability of NC ligands. Modulating the NC surface requires the necessary tools to monitor chemical reactions. One commonly utilized analytical method to achieve targeted surface compositions is 1H nuclear magnetic resonance (NMR) spectroscopy. Here we describe our use of 1H NMR spectroscopy to monitor chemical reactions at CdSe and PbS NC surfaces to identify ligand specific reactivity. However, seemingly straightforward ligand exchange reactions can vary widely depending on the NC materials and anchoring group. Some non-native X-type ligands will irreversibly displace native ligands. Other ligands exist in equilibrium with native ligands. Depending on the application, it is important to understand the nature of exchange reactions. This level of understanding can be obtained by extracting exchange ratios, exchange equilibrium, and reaction mechanism information from 1H NMR spectroscopy to establish precise NC reactivity.Reactivity that occurs through multiple, parallel ligand exchange mechanisms can involve both the liberation of metal-based Z-type ligands in addition to reactivity of X-type ligands. In these reactions, 1H NMR spectroscopy fails to discern between an X-type oleate or a Z-type Pb(oleate)2 because only the alkene resonance of the organic constituent is probed by this method. Multiple, parallel reaction pathways occur when thiol ligands are introduced to oleate-capped PbS NCs. This necessitated the use of synergistic characterization methods including 1H NMR spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and inductively coupled plasma mass spectrometry (ICP-MS) to characterize both surface-bound and liberated ligands.Similar analytical methods have been employed to probe the NC topology, which is an important, but often overlooked, component to NC reactivity given the facet-specific reactivity of PbS NCs. Through the tandem use of NMR spectroscopy and ICP-MS, we have monitored the liberation of Pb(oleate)2 as an L-type ligand is titrated to the NC to determine the quantity and equilibrium of Z-type ligands. By studying a variety of NC sizes, we correlated the number of liberated ligands with the size-dependent topology of PbS NCs.Lastly, we incorporate redox-active chemical probes into our toolbox to study NC surface defects. We describe how the site-specific reactivity and relative energetics of redox-active surface-based defects are elucidated using redox probes and show that this reactivity is highly dependent on the surface composition. This Account is designed to encourage readers to consider the necessary characterization techniques needed establish a molecular-level understanding of NC surfaces in their own work.

Unexpected Reactivity of Cationic-to-Cationic Thiolate Ligand-Exchange Reaction on Au25 Clusters.

Thiolate-protected molecular noble metal clusters have attracted significant attention due to their unique physicochemical properties, which make them applicable in diverse fields such as catalysis, sensing, and bioimaging. Ligand-exchange reactions are a crucial technique for synthesizing and functionalizing these clusters, as they allow for the introduction of new ligands onto the cluster surface, which can alter their properties. While numerous studies have investigated neutral-to-neutral, neutral-to-anionic, and neutral-to-cationic ligand-exchange reactions, the cationic-to-cationic ligand-exchange reaction has never been reported, making the study of such reactions intriguing. In this study, the cationic ligand-exchange reaction on Au25(4-PyET-CH3+)x(4-PyET)18-x (x ≈ 9) clusters, which contain both neutral and cationic ligands in nearly equivalent amounts, was investigated. Contrary to our expectation that the cationic-to-cationic ligand-exchange reaction would be suppressed due to Coulombic repulsion between the surface cationic ligands and incoming cationic ligands, the originally existing cationic ligand was selectively exchanged. The choice of counterions for cationic ligands played a crucial role in controlling the selectivity of ligand exchange. For instance, bulky and hydrophobic counterions such as PF6- can cause steric hindrance and reduce Coulombic repulsion, which promotes cationic-to-cationic ligand exchange. Conversely, counterions like Cl- can lead to neutral-to-cationic ligand exchange due to reduced steric hindrance and increased Coulombic repulsion between cationic ligands. These findings provide a novel method for tailoring the properties of molecular gold clusters through controlled ligand exchange without requiring the design of thiolate ligands with varying geometrical structures.

Ultrathin thin-film composite membrane integrated with MoS2 conjugated with thiol ligands for isopropanol dehydration by pervaporation

In recent years, transition metal dichalcogenides (TMDs) have garnered much significant attention for their potential in fabricating high-performance membranes and applications in water treatment. In the present study, molybdenum disulfide (MoS2) nanosheets were modified using organic thiols to synthesize amino, hydroxyl, and carboxyl-functionalized MoS2. These modified nanosheets were subsequently integrated into polyamide matrix to develop thin-film nanocomposite (TFN) membranes for dehydration of isopropanol-water mixtures through pervaporation. A comprehensive examination of the impact of incorporating functionalized MoS2 on the physical and chemical properties and separation performance of the resulting TFN membranes was carried out. Embedding MoS2 created a bumpy structure with protuberances on the membrane surface. Amine groups from the modified MoS2 played a crucial role in crosslinking with trimesoyl chloride during interfacial polymerization, contributing to an enhanced crosslinking degree in the membrane. Compared with the pristine membrane, hydroxyl and carboxyl-modified MoS2, the TFN membrane incorporated with amine-modified MoS2 exhibited the highest separation performance with total flux of 1438 g m−2 h−1 and water content in permeate of 99.37 wt% for separating 70 wt% isopropanol aqueous solution. Remarkably, the TFN membrane exhibited a robust performance under high operating temperatures and high feed water concentrations, demonstrating its resilience in challenging conditions. Furthermore, the membrane exhibited stable long-term operational performance, highlighting its potential for pervaporation dehydration applications in the industry. The insights gained from this study contribute to the ongoing development of advanced membrane technologies based on TMDs.

Three generations of thiolated cyclodextrins: A direct comparison of their mucus permeating and mucoadhesive properties

AimThis study aims to compare the mucus permeating and mucoadhesive properties of three generations of thiolated cyclodextrins (CDs). MethodsFree thiol groups of thiolated γ-CDs (CD-SH) were S-protected with 2-mercaptonicotinic acid (MNA), leading to a second generation of thiolated CDs (CD-SS-MNA) and with 2 kDa polyethylene glycol (PEG) bearing a terminal thiol group leading to a third generation of thiolated CDs (CD-SS-PEG). The structure of these thiolated CDs was confirmed and characterized by FT-IR, 1H NMR and colorimetric assays. Thiolated CDs were evaluated regarding viscosity, mucus diffusion, and mucoadhesion. ResultsThe viscosity of the mixture of CD-SH, CD-SS-MNA, or CD-SS-PEG with mucus increased up to 11-, 16-, and 14.1-fold compared to unmodified CD within 3 hours, respectively. Mucus diffusion increased in the following rank order: unprotected CD-SH < CD-SS-MNA < CD-SS-PEG. The residence time of CD-SH, CD-SS-MNA, and CD-SS-PEG on porcine intestine was up to 9.6-, 12.55-, and 11.2-fold prolonged compared to native CD, respectively. ConclusionAccording to these results, S-protection of thiolated CDs can be a promising approach to improve their mucus permeating and mucoadhesive properties. Statement of significanceThree generations of thiolated cyclodextrins (CDs) with different types of thiol ligands have been synthesized to improve mucus interaction. 1st generation of thiolated CDs was synthesized by converting hydroxyl groups into thiols by reaction with Thiourea. For 2nd generation, free thiol groups were S-protected by reaction with 2-mercaptonicotinic acid (MNA), resulting in high reactive disulfide bonds. For 3rd generation, terminally thiolated short PEG chains (2 kDa) were used for S-protection of thiolated CDs. Mucus penetrating properties were found to be increased as follows: 1st generation < 2nd generation < 3rd generation. Furthermore, mucoadhesive properties were improved in the following rank order: 1st generation < 3rd generation < 2nd generation. This study suggests that the S-protection of thiolated CDs can enhance mucus penetrating and mucoadhesive properties.

Ligand engineering with heterocyclic aromatic thiol doped carbon quantum dots

Insights on the origin of photoluminescence (PL) in carbon quantum dots (CQDs) are useful to explore its application in the technological and biomedical fields. Herein, we demonstrate the use of three heterocyclic aromatic thiol ligands (namely, 2-mercaptobenzimidazole (MBI), 2-mercaptobenzothiazole (MBT) and 2-mercaptobenzoxazole (MBO)) doped CQDs (CQDs-MBI, CQDs-MBT and CQDs-MBO) to address the significance of heteroatoms in the optical and electrochemical characteristics of CQDs. Interestingly, we found that nitrogen moieties played a vital role in tailoring the optical and electrochemical properties of CQDs-MBI, CQDs-MBT and CQDs-MBO. Owing to the enriched nitrogen moieties and less surface trap states in CQDs-MBI, which exhibits superior quantum yield (QY) and lifetime than CQDs-MBT and CQDs-MBO. Moreover, for the CQDs-MBI and CQDs-MBT we achieved two sets of emission whereas for the CQDs-MBO attained three sets, also all these CQDs display both excitation independent and dependent emission behavior due to the distinct surface states which is peculiar to existing literature reports. To substantiate the importance of ligand engineering with these three different CQDs, we further investigated the electrochemical characteristics as well. These tunable optical and electrochemical properties of the three different CQDs suggest great scope in the development of new luminescent and sensor materials.

Using Surface-Enhanced Raman Spectroscopy to Unravel the Wingtip-Dependent Orientation of N-Heterocyclic Carbenes on Gold Nanoparticles

N-Heterocyclic carbenes (NHCs) are an attractive alternative to thiol ligands when forming self-assembled monolayers on noble-metal surfaces; however, relative to the well-studied thiol monolayers, comparatively little is known about the binding, orientation, and packing of NHC monolayers. Herein, we combine surface-enhanced Raman spectroscopy (SERS) and first-principles theory to investigate how the alkyl "wingtip" groups, i.e., those attached to the nitrogens of N-heterocyclic carbenes, affect the NHC orientation on gold nanoparticles. Consistent with previous literature, smaller wingtip groups lead to stable flat configurations; surprisingly, bulkier wingtips also have stable flat configurations likely due to the presence of an adatom. Comparison of experimental SERS results with the theoretically calculated spectra for flat and vertical configurations shows that we are simultaneously detecting both NHC configurations. In addition to providing information on the adsorbate geometry, this study highlights the extreme SERS enhancement of vibrational modes perpendicular to the surface.

Molecular engineering metal-organic frameworks as efficient electrochemical catalysis for water oxidation.

Metal-organic framework (MOF) solids with their variable functionalities are relevant for energy conversion technologies. However, the development of electroactive and stable MOFs for electrocatalysis still faces challenges. Here, we design a molecularly engineered MOF system featuring a 2D coordination network based on mercaptan-metal links (e.g., nickel, as for Ni(DMBD)-MOF). The crystal structure is solved from microcrystals by continuous rotation electron diffraction (cRED) technique. Computational results indicate a metallic electronic structure of Ni(DMBD)-MOF due to the Ni-S coordination, highlighting the effective design of the thiol ligand for enhancing electro-conductivity. Additionally, both experimental and theoretical studies indicate that (DMBD)-MOF offers advantages in the electrocatalytic oxygen evolution reaction (OER) over non-thiol (e.g., 1,4-benzene dicarboxylic acid) analog (BDC)-MOF, because it poses fewer energy barriers during the rate-limiting *O intermediate formation step. Iron-substituted NiFe(DMBD)-MOF achieves a current density of 100 mA·cm-2 at a small overpotential of 280mV, indicating a new MOF platform for efficient OER catalysis. This article is protected by copyright. All rights reserved.

Classical Force Field Parameters for InP and InAs Quantum Dots with Various Surface Passivations.

Classical molecular dynamics (MD) simulations on realistic colloidal quantum dot (QD) systems are often hampered by missing force field (FF) parameters for an accurate description of the QD-ligand interface. However, such calculations are of major interest, specifically for studying the surface chemistry of colloidal nanocrystals. In this work, we have utilized a previously published stochastic optimization algorithm to obtain FF parameters for InP and InAs QDs capped by Cl, amine, carboxylate, and thiolate ligands. Our FF parameters are interfaced with well-established FFs for organic molecules, allowing for the simulation of InP and InAs QDs with a broad range of organic ligands in explicit apolar solvents. The quality of our FF parameters was assessed by comparing properties of the classical MD simulations with ab initio MD simulations and experimental and theoretical values from the literature.

Hybrid Ligand Polymerization for Weakly Confined Lead Halide Perovskite Quantum Dots

Rational ligand passivation is essential to achieve a higher performance of weakly confined lead halide perovskite quantum dots (PQDs) via a mechanism of surface chemistry and/or microstrain. In situ passivation with 3-mercaptopropyltrimethoxysilane (MPTMS) produces CsPbBr3 PQDs with an enhanced photoluminescence quantum yield (PLQY, ΦPL) of up to 99%; meanwhile, charge transport of the PQD film can be enhanced by one order of magnitude. Herein, we examine the effect of the molecular structure of MPTMS as the ligand exchange agent in comparison to octanethiol. Both thiol ligands promote crystal growth of PQDs, inhibit nonradiative recombination, and cause blue-shifted PL, while the silane moiety of MPTMS manipulates surface chemistry and outperforms owing to its unique cross-linking chemistry characterized by FTIR vibrations at 908 and 1641 cm-1. Emergence of the diagnostic vibrations is ascribed to hybrid ligand polymerization arising from the silyl tail group that confers the advantages of narrower size dispersion, lower shell thickness, more static surface binding, and higher moisture resistance. In contrast, the superior electrical property of the thiol-passivated PQDs is mostly determined by the covalent S-Pb bonding on the interface.

Role of Non-covalent Interaction toward Conductivity in a One-Dimensional Tube-like Silver-Thiolate Structure

We report a new one-dimensional tube-like atomically precise silver-thiolate polymer–chain. The structure consists of Ag14(SR)18 as the building units. Silver atoms are linked with the thiol ligand to form the one-dimensional structure. The non-covalent interactions like argentophilic and C–H···H–C interactions appear as crucial for the long-range structural arrangement. Electronic structure calculations show its semiconductor-type band structure with a band gap of about 2 eV. Conductivity measurements on the single crystal implies its facile charge transfer pathway along the one-dimensional chain. The variation of conductivity between the single crystal and the drop-cast film implies the role of argentophilic and C–H···H–C interactions in the preferred charge transfer pathway.

Effects of ligand replacement in thiolated gold nanoclusters

Thiolate ligands are vital to thiolated gold nanoclusters (AuNCs). Considering the computational price, theoretical works practically replace –SR (R is the long organic group) in Aum(SR)n by –SH or –SCH3. However, the effects of the ligand replacement were seldom examined. Here, Au16(SR)12, Au21(SR)15 and Au24(SR)20 with experimentally used –SCH2C6H5 and other ligands including –SH, –SCH3, –SC3H7 were applied to examine the detailed effects. The results on structure, energy of frontier orbital and optical property suggest that using –SCH3 can generally reproduce the results with –SCH2C6H5. This work is helpful for understanding the effects of the thiolate ligands thoroughly.

Structural incorporation of iron influences biomethylation potential of mercury sulfide

Mercury and ferrous iron commonly co-exist in anaerobic environments, the hotspots of microbial mercury methylation that leads to formation of neurotoxic methylmercury. However, the influence of ferrous iron on mercury bioavailability and methylation remains unclear. Here, we discover that microbial methylmercury production is inhibited by iron addition in a non-monotonical manner, reaching the minimal level at the initial molar ratio of dissolved Fe/Hg as 1/3, when highly aggregated Hg–S–Fe nanoparticles occur and prevent the nanoparticle–bacteria interactions. The dominant mercury species formed upon Hg–S–Fe co-precipitation is iron-incorporated nano-metacinnabar with short-range structural disorder. The methylation potential of this mercury species is inversely correlated with the aggregation state of nanoparticles. The non-monotonical trends of the aggregation state and subsequent methylation of nano-metacinnabar are due to the opposite effects of ferrous iron on the nucleation and particle attachment that determine the formation of nanoparticle aggregates. Increased Fe/Hg ratio hinders particle nucleation and thus decreases the density of particle monomers for aggregation. However, Fe substitution of sub-surface Hg weakens the inner-sphere coordination of surface Hg with natural thiol ligands and consequently enhances nano-metacinnabar aggregation. This new mechanistic insight is important for assessing and minimizing the risks of mercury methylation, and informs how intertwined iron and sulfur cycling may influence metal bioavailability in the changing environment.

Methylmercury Degradation by Trivalent Manganese.

Methylmercury (MeHg) is a potent neurotoxin and has great adverse health impacts on humans. Organisms and sunlight-mediated demethylation are well-known detoxification pathways of MeHg, yet whether abiotic environmental components contribute to MeHg degradation remains poorly known. Here, we report that MeHg can be degraded by trivalent manganese (Mn(III)), a naturally occurring and widespread oxidant. We found that 28 ± 4% MeHg could be degraded by Mn(III) located on synthesized Mn dioxide (MnO2-x) surfaces during the reaction of 0.91 μg·L-1 MeHg and 5 g·L-1 mineral at an initial pH of 6.0 for 12 h in 10 mM NaNO3 at 25 °C. The presence of low-molecular-weight organic acids (e.g., oxalate and citrate) substantially enhances MeHg degradation by MnO2-x via the formation of soluble Mn(III)-ligand complexes, leading to the cleavage of the carbon-Hg bond. MeHg can also be degraded by reactions with Mn(III)-pyrophosphate complexes, with apparent degradation rate constants comparable to those by biotic and photolytic degradation. Thiol ligands (cysteine and glutathione) show negligible effects on MeHg demethylation by Mn(III). This research demonstrates potential roles of Mn(III) in degrading MeHg in natural environments, which may be further explored for remediating heavily polluted soils and engineered systems containing MeHg.

Glutathione and phytochelatins jointly allow intracellular and extracellular detoxification of cadmium in the liverwort Marchantia polymorpha

Plants have evolved a set of mechanisms that control and respond to the uptake and accumulation of both essential and non-essential metals, including chelation and sequestration of these elements by thiol ligands, such as glutathione and phytochelatins. Indeed, such thiol peptides can chelate some metals, quickly form thiol-metal complexes, and segregate them in the vacuolar compartment. Reasonably, conceptually similar mechanisms can be assumed to be responsible for the transport of metal complexes ̶ in particular thiol-cadmium complexes ̶ across the plasma membrane, with the consequent release of this toxic metal in the extracellular environment. Such hypothesis, focusing on prevention and detoxification mechanisms, was here verified in axenically-grown gametophytes of the model liverwort Marchantia polymorpha, exposed to three different cadmium concentrations over five exposure times. From the data obtained, it can be deduced that the cell wall of M. polymorpha moderately reduced the influx of cadmium into the cells, since it was rapidly saturated by this metal. At an intracellular level, cadmium induced the activity, but not the gene expression, of the phytochelatin synthase enzyme, leading to synthesis of phytochelatins. Moreover, both glutathione and phytochelatins chelated cadmium at the cytosolic level and allowed its detoxification, possibly involving tonoplast transporters belonging to type-C ABC subfamily (Mp7g13860 and Mp4g11930). Likewise, cadmium, glutathione and phytochelatins were released extracellularly, thus highlighting a possible novel role in cadmium detoxification, in a pH-dependent manner. The overall results suggest that, in M. polymorpha, glutathione and phytochelatins can accomplish intracellular and extracellular detoxification of cadmium.

Giving Gold Wings: Ultrabright and Fragmentation Free Mass Spectrometry Reporters for Barcoding, Bioconjugation Monitoring, and Data Storage

AbstractThe widespread application of laser desorption/ionization mass spectrometry (LDI‐MS) highlights the need for a bright and multiplexable labeling platform. While ligand‐capped Au nanoparticles (AuNPs) have emerged as a promising LDI‐MS contrast agent, the predominant thiol ligands suffer from low ion yields and extensive fragmentation. In this work, we develop a N‐heterocyclic carbene (NHC) ligand platform that enhances AuNP LDI‐MS performance. NHC scaffolds are tuned to generate barcoded AuNPs which, when benchmarked against thiol‐AuNPs, are bright mass tags and form unfragmented ions in high yield. To illustrate the transformative potential of NHC ligands, the mass tags were employed in three orthogonal applications: monitoring a bioconjugation reaction, performing multiplexed imaging, and storing and reading encoded information. These results demonstrate that NHC‐nanoparticle systems are an ideal platform for LDI‐MS and greatly broaden the scope of nanoparticle contrast agents.

Giving Gold Wings: Ultrabright and Fragmentation Free Mass Spectrometry Reporters for Barcoding, Bioconjugation Monitoring, and Data Storage.

The widespread application of laser desorption/ionization mass spectrometry (LDI-MS) highlights the need for a bright and multiplexable labeling platform. While ligand-capped Au nanoparticles (AuNPs) have emerged as a promising LDI-MS contrast agent, the predominant thiol ligands suffer from low ion yields and extensive fragmentation. In this work, we develop a N-heterocyclic carbene (NHC) ligand platform that enhances AuNP LDI-MS performance. NHC scaffolds are tuned to generate barcoded AuNPs which, when benchmarked against thiol-AuNPs, are bright mass tags and form unfragmented ions in high yield. To illustrate the transformative potential of NHC ligands, the mass tags were employed in three orthogonal applications: monitoring a bioconjugation reaction, performing multiplexed imaging, and storing and reading encoded information. These results demonstrate that NHC-nanoparticle systems are an ideal platform for LDI-MS and greatly broaden the scope of nanoparticle contrast agents.

Fifty Years of Inorganic Biomimetic Chemistry: From the Complexation of Single Metal Cations to Polynuclear Metal Complexes by Multidentate Thiolate Ligands

AbstractThis article covers 50 years of coordination chemistry of transition metal complexes and metal‐sulfur aggregates involving thiolate‐incorporating ligands by reviewing selected examples. The studies in the coordination chemistry of sulfur‐rich ligands have been undoubtedly triggered and fed by the concomitant development of bioinorganic chemistry, particularly of iron‐sulfur enzymes. The review is broken down in five sections, which examine complexes of increasing nuclearity, including binuclear complexes based on compartmental macrocyclic ligands. We show also how ligand engineering has allowed the researchers in the field to control the nuclearity of the complexes, which was a particularly difficult task for sulfur‐based ligands, as thiolates show a strong tendency to coordinate to more than one metal cation at once.

A General and Scalable Approach to Sulfur-Doped Mono-/Bi-/Trimetallic Nanoparticles Confined in Mesoporous Carbon.

Metal nanoparticles confined in porous carbon materials have been widely used in various heterogeneous catalytic processes due to their enhanced activity and stability. However, fabrication of such catalysts in a facile and scalable way remains challenging. Herein, we report a general and scalable thiol-assisted strategy to synthesize sulfur-doped mono-/bi-/trimetallic nanoparticles confined in mesoporous carbon (S-M@MC, M = Pt, Pd, Rh, Co, Zn, etc.), involving only two synthetic steps, i.e., a hydrothermal process and pyrolysis. The strategy is based on coordination chemistry and hydro-phobic interaction that the metal precursors coordinated with the hydrophobic thiol ligands are located at the hydrophobic core of micelles, in situ confined in the hydrothermally prepared mesostructured polymer, and then converted into sulfur-doped metal nanoparticles confined in MC after pyrolysis. It is demonstrated that the S-PtCo@MC exhibits enhanced catalytic activity and improved durability toward acidic hydrogen evolution reaction due to the confinement effect and S-doping.