Tracking dendrites and solid electrolyte interphase formation with dynamic nuclear polarization-NMR spectroscopy.

Polymer-ceramic composite electrolytes enable safe implementation of Li metal batteries with potentially transformative energy density. Nevertheless, the formation of Li-dendrites and its complex interplay with the Li-metal solid electrolyte interphase (SEI) remain a substantial obstacle which is poorly understood. Here we tackle this issue by a combination of solid-state NMR spectroscopy and Overhauser dynamic nuclear polarization (DNP) which boosts NMR interfacial sensitivity through polarization transfer from the metal conduction electrons.

Composition and Structure of the solid electrolyte interphase on Na-Ion Anodes Revealed by Exo- and Endogenous Dynamic Nuclear Polarization─NMR Spectroscopy.

Sodium ion batteries (SIB) are among the most promising devices for large scale energy storage. Their stable and long-term performance depends on the formation of the solid electrolyte interphase (SEI), a nanosized, heterogeneous and disordered layer, formed due to degradation of the electrolyte at the anode surface. The chemical and structural properties of the SEI control the charge transfer process at the electrode-electrolyte interface, thus, there is great interest in determining these properties for understanding, and ultimately controlling, SEI functionality.

Insights into the CO Capture Characteristics within the Hierarchical Pores of Carbon Nanospheres Using Small-Angle Neutron Scattering.

Understanding adsorption processes at the molecular level has transformed the discovery of engineered materials for maximizing gas storage capacity and kinetics in adsorption-based carbon capture applications. In this work, we studied the molecular mechanism of gas (CO, H, methane, and ethane) adsorption inside an interconnected porous network of carbon. This was achieved by synthesizing novel macro-meso-microporous carbon (MC) nanospheres with interconnected pore structures.

Direct CO capture and conversion to fuels on magnesium nanoparticles under ambient conditions simply using water.

Converting CO directly from the air to fuel under ambient conditions is a huge challenge. Thus, there is an urgent need for CO conversion protocols working at room temperature and atmospheric pressure, preferentially without any external energy input. Herein, we employ magnesium (nanoparticles and bulk), an inexpensive and the eighth-most abundant element, to convert CO to methane, methanol and formic acid, using water as the sole hydrogen source.

Lithium silicate nanosheets with excellent capture capacity and kinetics with unprecedented stability for high-temperature CO capture.

An excessive amount of CO is the leading cause of climate change, and hence, its reduction in the Earth's atmosphere is critical to stop further degradation of the environment. Although a large body of work has been carried out for post-combustion low-temperature CO capture, there are very few high temperature pre-combustion CO capture processes. Lithium silicate (LiSiO), one of the best known high-temperature CO capture sorbents, has two main challenges, moderate capture kinetics and poor sorbent stability.

Gold cluster-loaded dendritic nanosilica: single particle luminescence and catalytic properties in the bulk.

We report a hybrid material in which surface anchoring-induced enhanced luminescence of AuQC@BSA clusters on high surface area dendritic fibrous nanosilica of 800 nm diameter enabled their luminescence imaging at a single particle level. The photophysical and structural properties of the hybrid material were characterized by various spectroscopic and microscopic techniques. Concomitant imaging using scattering and luminescence of such mesostructures and their response to analytes have been used to develop a chemical sensor.

Origin of the Hierarchical Structure of Dendritic Fibrous Nanosilica: A Small-Angle X-ray Scattering Perspective.

The discovery of dendritic fibrous nanosilica (DFNS) has attracted great attention to the field of catalysis, CO capture, drug delivery due to its distinct morphology, and pore size distribution. Despite extensive research, the understanding of the DFNS formation process and its internal structure remains incomplete as microscopy and gas sorption techniques were not able to provide necessary in-depth structural information due to their inherent limitations. In the current work, we present a structural model of DFNS derived using small-angle X-ray scattering (SAXS) supported by Xe nuclear magnetic resonance (NMR), which provided intricate details of DFNS and its internal structure.

Dendritic Fibrous Nanosilica (DFNS) for RNA Extraction from Cells.

Efficient RNA extraction is critical for all downstream molecular applications and techniques. Despite the availability of several commercial kits, there is an enormous scope to develop novel materials that have high binding and elution capacities. Here, we show that RNA from the cells can be extracted by dendritic fibrous nanosilica (DFNS) with higher efficiency than commercially available silicas.

Catalytic nanosponges of acidic aluminosilicates for plastic degradation and CO to fuel conversion.

The synthesis of solid acids with strong zeolite-like acidity and textural properties like amorphous aluminosilicates (ASAs) is still a challenge. In this work, we report the synthesis of amorphous "acidic aluminosilicates (AAS)", which possesses Brønsted acidic sites like in zeolites and textural properties like ASAs. AAS catalyzes different reactions (styrene oxide ring-opening, vesidryl synthesis, Friedel-Crafts alkylation, jasminaldehyde synthesis, m-xylene isomerization, and cumene cracking) with better performance than state-of-the-art zeolites and amorphous aluminosilicates.

Plasmonic colloidosomes of black gold for solar energy harvesting and hotspots directed catalysis for CO to fuel conversion.

In this work, we showed the tuning of the catalytic behavior of dendritic plasmonic colloidosomes (DPCs) by plasmonic hotspots. A cycle-by-cycle solution-phase synthetic protocol yielded high-surface-area DPCs by controlled nucleation-growth of gold nanoparticles. These DPCs, which had varying interparticle distances and particle-size distribution, absorb light over the entire visible region as well as in the near-infrared region of the solar spectrum, transforming gold into black gold.

Facile synthesis to tune size, textural properties and fiber density of dendritic fibrous nanosilica for applications in catalysis and CO capture.

Morphology-controlled nanomaterials such as silica play a critical role in the development of technologies for use in the fields of energy, environment (water and air pollution) and health. Since the discovery of Stöber's silica, followed by the discovery of mesoporous silica materials (MSNs) such as MCM-41 and SBA-15, a surge in the design and synthesis of nanosilica with various sizes, shapes, morphologies and textural properties (surface area, pore size and pore volume) has occurred. Dendritic fibrous nanosilica (DFNS; also known as KCC-1) is one of the recent discoveries in morphology-controlled nanomaterials.

Self-Assembled Photonic Crystals of Monodisperse Dendritic Fibrous Nanosilica for Lasing: Role of Fiber Density.

Photonic crystals are essentially a periodic ("crystalline") arrangement of dielectric nanoparticles that respond in unison to incident light. They can be used to harvest light in various applications such as photocatalysis, solar cells, and lasing. In this work, we prepared the photonic crystals of dendritic fibrous nanosilica (DFNS) by their self-assembly.

Negative Photochromism Based on Molecular Diffusion between Hydrophilic and Hydrophobic Particles in the Solid State.

A colored hybrid based on a merocyanine adsorbed in a nanoporous-silica-composed dendritic fibrous silica was prepared by adsorption onto the nanoporous silica from a spiropyran solution during UV irradiation (photoinduced adsorption). The obtained red hybrid thus exhibited negative photochromism by visible-light irradiation. The hybrid was further combined with an organophilic clay by a solid-state mixing without using solvent to achieve excellent reversibility of the color change, which was thought to be achieved by molecular diffusion through the two materials, where nanoporous silica and organophilic clay accommodated the colored (merocyanine) and colorless (photogenerated spiropyran) isomers, respectively.

Unraveling the Formation Mechanism of Dendritic Fibrous Nanosilica.

We studied the formation mechanism of dendritic fibrous nanosilica (DFNS) that involves several intriguing dynamical steps. Through electron microscopy and real-time small-angle X-ray scattering studies, it has been demonstrated that the structural evolution of bicontinuous microemulsion droplets (BMDs) and their subsequent coalescence, yielding nanoreactor template, is responsible for to the formation of complex DFNS morphology. The role of cosurfactant has been found to be quite crucial, which allowed the understanding of this intricate mechanism involving the complex interplay of self-assembly, dynamics of BMDs formation, and coalescence.

Photochromism of a Spiropyran in the Presence of a Dendritic Fibrous Nanosilica; Simultaneous Photochemical Reaction and Adsorption.

The photoinduced adsorption of a photochromic spiropyran (1-(2-hydroxyethyl)-3,3-dimethylindolino-6'-nitrobenzopyrylospiran) onto a dendritic fibrous nanosilica (DFNS) was investigated. By UV irradiation, the colorless suspension containing the spiropyran and DFNS changed to blue without stirring, while it turned to red by the irradiation under stirring. These two colors were attributed to the photogenerated merocyanine in a non polar environment (in toluene, blue) and on a protic environment (on DFNS, red).

Dendritic Fibrous Nanosilica for Catalysis, Energy Harvesting, Carbon Dioxide Mitigation, Drug Delivery, and Sensing.

Morphology-controlled nanomaterials such as silica play a crucial role in the development of technologies for addressing challenges in the fields of energy, environment, and health. After the discovery of Stöber silica, followed by that of mesoporous silica materials, such as MCM-41 and SBA-15, a significant surge in the design and synthesis of nanosilica with various sizes, shapes, morphologies, and textural properties has been observed in recent years. One notable invention is dendritic fibrous nanosilica, also known as KCC-1.

Room temperature transmetallation from tris(pentafluorophenyl)borane to cyclometallated iridium(iii).

Transmetallation reactions involving organoboron reagents and transition metals are legion in synthetic organometallic chemistry and homogeneous catalysis. Triarylboranes (BAr) have been observed to participate in transmetallation reactions with many transition metals, typically following abstraction of an alkyl (R) or hydride ligand by the Lewis acidic borane. Here, an unusual transmetallation strategy is described where an aryl group from a borane replaces a weakly coordinated PF ligand.

Bis-cyclometalated iridium complexes with electronically modified aryl isocyanide ancillary ligands.

In this work we report a study on the effect of systematic ancillary ligand modifications on electrochemical and photophysical properties of cationic biscyclometalated bis(arylisocyanide)iridium(iii) complexes. Nine new Ir(iii) complexes were synthesized using three different cyclometalating (C^N) ligands (2,4-difluorophenylpyridine (Fppy), 2-benzothienylpyridine (btp), and 2-phenylbenzothiazole (bt)) with three aryl isocyanide ancillary ligands (2,4-dimethoxyphenyl isocyanide (CNAr), 3,5-bis(trifluoromethyl)phenyl isocyanide (CNAr) and 4-nitrophenyl isocyanide (CNAr)). Systematic modifications of ancillary ligands with electron-donating or electron-withdrawing groups have a very minor influence on the positions of the absorption and emission bands, suggesting that aryl isocyanide ancillary ligands minimally perturb the primarily ligand-centered emissive states, but still can control the dynamics of the excited state.

Main Group Lewis Acid-Mediated Transformations of Transition-Metal Hydride Complexes.

This Review highlights stoichiometric reactions and elementary steps of catalytic reactions involving cooperative participation of transition-metal hydrides and main group Lewis acids. Included are reactions where the transition-metal hydride acts as a reactant as well as transformations that form the metal hydride as a product. This Review is divided by reaction type, illustrating the diverse roles that Lewis acids can play in mediating transformations involving transition-metal hydrides as either reactants or products.

Steric and Electronic Influence of Aryl Isocyanides on the Properties of Iridium(III) Cyclometalates.

Cyclometalated iridium complexes with efficient phosphorescence and good electrochemical stability are important candidates for optoelectronic devices. Isocyanide ligands are strong-field ligands: when attached to transition metals, they impart larger HOMO-LUMO energy gaps, engender higher oxidative stability at the metal center, and support rugged organometallic complexes. Aryl isocyanides offer more versatile steric and electronic control by selective substitution at the aryl ring periphery.

Manipulating the Excited States of Cyclometalated Iridium Complexes with β-Ketoiminate and β-Diketiminate Ligands.

A series of cyclometalated iridium complexes with β-ketoiminate and β-diketiminate ligands are described. Two different cyclometalating (C^N) ligands-2-phenylpridine (ppy) and 2-phenylbenzothiazole (bt)-are used in concert with three different ancillary (LX) ligands-a phenyl-substituted β-ketoiminate (acNac(Me)), a phenyl-substituted β-diketiminate (NacNac(Me)), and a fluorinated version of the β-diketiminate (NacNac(CF3))-to furnish a suite of six complexes. The complexes are prepared by metathesis reactions of chloro-bridged dimers [Ir(C^N)2(μ-Cl)]2 with potassium or lithium salts of the ancillary LX ligand.

A metal-containing nucleoside that possesses both therapeutic and diagnostic activity against cancer.

Nucleoside transport is an essential process that helps maintain the hyperproliferative state of most cancer cells. As such, it represents an important target for developing diagnostic and therapeutic agents that can effectively detect and treat cancer, respectively. This report describes the development of a metal-containing nucleoside designated Ir(III)-PPY nucleoside that displays both therapeutic and diagnostic properties against the human epidermal carcinoma cell line KB3-1.

Suzuki-Miyaura coupling of arylboronic acids to gold(iii).

Gold(iii) is prominent in catalysis, but its organometallic chemistry continues to be restricted by synthesis. Metal-carbon bond formation often relies on organometallic complexes of electropositive elements, including lithium and magnesium. The redox potential of gold(iii) interferes with reactions of these classic reagents.

Cyclometalated iridium(III) complexes with deoxyribose substituents.

Fundamental study of enzymatic nucleoside transport suffers for lack of optical probes that can be tracked noninvasively. Nucleoside transporters are integral membrane glycoproteins that mediate the salvage of nucleosides and their passage across cell membranes. The substrate recognition site is the deoxyribose sugar, often with little distinction among nucleobases.