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By sulfurization of phosphaalkenes ( a) either (σ3,λ5)-phosphoranes ( b) or (σ3,λ3)-thiaphosphiranes ( c) are formed. In this study, Density Functional Theory (DFT) and coupled cluster (CCSD(T)) calculations have been carried out for model and experimental structures of (σ3,λ5)-phosphoranes and (σ3,λ3)-thiaphosphiranes to elucidate the factors influencing relative stabilities of b and c. According to the results of quantum chemical calculations, sterically bulky substituents make the phosphorane form more favored. Conversely, electronic effects of the most substituents provide higher stability for thiaphosphirane isomers. The only exception has been found in the cases where the substituent at the phosphorus atom possesses π-donor and σ-acceptor properties (e.g., in the case of amino group) and the substituents at carbon atom exhibit σ-donor/π-acceptor effects (e.g., silyl groups). The stability of the cyclic form c decreases further, if the substituents at the carbon atom are amino groups. In this case, a quite unusual structure has been theoretically predicted, which is considerably different from those of the hitherto known phosphoranes. It indicates a pyramidal configuration at the phosphorus atom and can be conventionally presented as a donor-acceptor adduct of diaminocarbene with thioxophosphine. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Expression of concern for 'Highly effective photodynamic inactivation of E. coli using gold nanorods/SiO 2 core-shell nanostructures with embedded verteporfin' by Kostiantyn Turcheniuk et al. , Chem. Commun. , 2015, 51 , 16365-16368, https://doi.org/10.1039/C5CC06738C.

Expression of concern for 'Plasmonic photothermal destruction of uropathogenic E. coli with reduced graphene oxide and core/shell nanocomposites of gold nanorods/reduced graphene oxide' by Kostiantyn Turcheniuk et al. , J. Mater. Chem. B , 2015, 3 , 375-386, https://doi.org/10.1039/C4TB01760A.

Expression of concern for 'Reduced graphene oxide nanosheets decorated with AuPd bimetallic nanoparticles: a multifunctional material for photothermal therapy of cancer cells' by Gitashree Darabdhara et al. , J. Mater. Chem. B , 2015, 3 , 8366-8374, https://doi.org/10.1039/C5TB01704A.

Expression of concern for 'Particle-based photodynamic therapy based on indocyanine green modified plasmonic nanostructures for inactivation of a Crohn's disease-associated Escherichia coli strain' by Roxana Jijie et al. , J. Mater. Chem. B , 2016, 4 , 2598-2605, https://doi.org/10.1039/C5TB02697K.

Safety concerns of traditional liquid electrolytes, especially when paired with lithium (Li) metal anodes, have stimulated research of solid polymer electrolytes (SPEs) to exploit the superior thermal and mechanical properties of polymers. Polyphosphazenes are primarily known for their use as flame retardant materials and have demonstrated high Li-ion conductivity owing to their highly flexible P = N backbone which promotes Li-ion conduction via inter- and intrachain hopping along the polymer backbone. While polyphosphazenes are largely unexplored as SPEs in the literature, a few existing examples showed promising ionic conductivity. By anchoring the anion to the polymer backbone, one may primarily allow the movement of Li ions, alleviating the detrimental effects of polarization that are common in conventional dual-ion conducting SPEs. Anion-anchored SPEs, known as single Li-ion conducting solid polymer electrolytes (SLiC-SPEs), exhibit high Li-ion transference numbers ( t Li + ), which limits Li dendrite growth, thus further increasing the safety of SPEs. However, previously reported SLiC-SPEs suffer from inadequate ionic conductivity, small electrochemical stability windows (ESWs), and limited cycling stability. Herein, we report three polyphosphazene-based SLiC-SPEs comprising lithiated polyphosphazenes. The SLiC polyphosphazenes were prepared through a facile synthesis route, opening the door for enhanced tunability of polymer properties via facile macromolecular nucleophilic substitution and subsequent lithiation. State-of-the-art characterization techniques, such as differential scanning calorimetry (DSC), electrochemical impedance spectroscopy (EIS), and solid-state nuclear magnetic resonance spectroscopy (ssNMR) were employed to probe the effect of the polymer structure on Li-ion dynamics and other electrochemical properties. Produced SPEs showed thermal stability up to ∼208 °C with ionic conductivities comparable to that of the best-reported SLiC-SPEs that definitively comprise no solvents or plasticizers. Among the three lithiated polyphosphazenes, the SPE containing dilithium poly[bis(trifluoroethylamino)phosphazene] (pTFAP2Li) exhibited the most promising electrochemical characteristics with t Li + of 0.76 and compatibility with both Li metal anodes and LiFePO 4 (LFP) cathodes; through 40 cycles at 100 °C, the PEO-pTFAP2Li blend showed 81.2% capacity utilization and 86.8% capacity retention. This work constitutes one of the first successful demonstrations of the cycling performance of a true all-solid-state Li-metal battery using SLiC polyphosphazene SPEs., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Current lithium-ion battery separators made from polyolefins such as polypropylene and polyethylene generally suffer from low porosity, low wettability, and slow ionic conductivity and tend to perform poorly against heat-triggering reactions that may cause potentially catastrophic issues, such as fire. To overcome these limitations, here we report that a porous composite membrane consisting of poly(vinylidene fluoride- co -hexafluoropropylene) nanofibers functionalized with nanodiamonds (NDs) can realize a thermally resistant, mechanically robust, and ionically conductive separator. We critically reveal the role of NDs in the polymer matrix of the membrane to improve the thermal, mechanical, crystalline, and electrochemical properties of the composites. Taking advantages of these characteristics, the ND-functionalized nanofiber separator enables high-capacity and stable cycling of lithium cells with LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) as the cathode, much superior to those using conventional polyolefin separators in otherwise identical cells.

We report on a new synthesis pathway for Mg n -propoxide nanowires (NWs) from Mg ethoxide nanoparticles using a simple alkoxy ligand exchange reaction followed by condensation polymerization in n -propanol. In order to uncover the morphology-structure correlation in the metal alkoxide family, we employed a powerful range of state-of-the-art characterization techniques. The morphology transformation from nanoparticles to nanowires was demonstrated by time-lapse SEM micrographs. Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (such as 1 H NMR and solid-state 13 C cross-polarization (CP)-MAS NMR) illustrated the replacement of ethyl by n -propyl and metal alkoxide condensation polymerization. We identified chemical formulas of the products also using NMR spectroscopy. The crystal structure simulation of Mg ethoxide particles and Mg n -propoxide NWs provided insights on how the ligand exchange and the associated increase in the fraction of OH groups greatly enhanced Mg alkoxide bonding and enabled a higher degree of coordination polymerization to facilitate the formation and growth of the Mg n -propoxide NWs. The discovered synthesis method could be extended for the fabrication of other metal alkoxide (nano) structures with various morphologies.

All-solid-state lithium (Li) metal and lithium-ion batteries (ASSLBs) with inorganic solid-state electrolytes offer improved safety for electric vehicles and other applications. However, current inorganic ASSLB manufacturing technology suffers from high cost, excessive amounts of solid-state electrolyte and conductive additives, and low attainable volumetric energy density. Such a fabrication method involves separate fabrications of sintered ceramic solid-state electrolyte membranes and ASSLB electrodes, which are then carefully stacked and sintered together in a precisely controlled environment. Here we report a disruptive manufacturing technology that offers reduced manufacturing costs and improved volumetric energy density in all solid cells. Our approach mimics the low-cost fabrication of commercial Li-ion cells with liquid electrolytes, except that we utilize solid-state electrolytes with low melting points that are infiltrated into dense, thermally stable electrodes at moderately elevated temperatures (~300 °C or below) in a liquid state, and which then solidify during cooling. Nearly the same commercial equipment could be used for electrode and cell manufacturing, which substantially reduces a barrier for industry adoption. This energy-efficient method was used to fabricate inorganic ASSLBs with LiNi 0.33 Mn 0.33 Co 0.33 O 2 cathodes and both Li 4 Ti 5 O 12 and graphite anodes. The promising performance characteristics of such cells open new opportunities for the accelerated adoption of ASSLBs for safer electric transportation.

Technologically important composites with enhanced thermal and mechanical properties rely on the reinforcement by the high specific strength ceramic nanofibers or nanowires (NWs) with high aspect ratios. However, conventional synthesis routes to produce such ceramic NWs have prohibitively high cost. Now, direct transformation of bulk Mg-Li alloys into Mg alkoxide NWs is demonstrated without the use of catalysts, templates, expensive or toxic chemicals, or any external stimuli. This mechanism proceeds through the minimization of strain energy at the boundary of phase transformation front leading to the formation of ultra-long NWs with tunable dimensions. Such alkoxide NWs can be easily converted in air into ceramic MgO NWs with similar dimensions. The impact of the alloy grain size and Li content, synthesis temperature, inductive and steric effects of alkoxide groups on the diameter, length, composition, ductility, and oxidation of the produced NWs is discussed., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Metal fluoride conversion cathodes offer a pathway towards developing lower-cost Li-ion batteries. Unfortunately, such cathodes suffer from extremely poor performance at elevated temperatures, which may prevent their use in large-scale energy storage applications. Here we report that replacing commonly used organic electrolytes with solid polymer electrolytes may overcome this hurdle. We demonstrate long-cycle stability for over 300 cycles at 50 °C attained in high-capacity (>450 mAh g -1 ) FeF 2 cathodes. The absence of liquid solvents reduced electrolyte decomposition, while mechanical properties of the solid polymer electrolyte enhanced cathode structural stability. Our findings suggest that the formation of an elastic, thin and homogeneous cathode electrolyte interphase layer on active particles is a key for stable performance. The successful operation of metal fluorides at elevated temperatures opens a new avenue for their practical applications and future successful commercialization.

Fabrication and applications of lightweight, high load-bearing, thermally stable composite materials would benefit greatly from leveraging the high mechanical strength of ceramic nanowires (NWs) over conventional particles or micrometer-scale fibers. However, conventional synthesis routes to produce NWs are rather expensive. Recently we discovered a novel method to directly convert certain bulk bimetallic alloys to metal-organic NWs at ambient temperature and pressure. This method was demonstrated by a facile transformation of polycrystalline aluminum-lithium (AlLi) alloy particles to aluminum alkoxide NWs, which can be further transformed to mechanically robust aluminum oxide (Al 2 O 3 ) NWs. However, the transformation mechanisms have not been clearly understood. Here, we conducted advanced materials characterization (via electron microscopy and nuclear magnetic resonance spectroscopies) and chemo-mechanical modeling to elucidate key physical and chemical mechanisms responsible for NWs formation. We further demonstrated that the content of Li metal in the AlLi alloy could be reduced to about 4 wt % without compromising the success of the NWs synthesis. This new mechanistic understanding may open new avenues for large-scale, low-cost manufacturing of NWs and nanofibers for a broad range of composites and flexible ceramic membranes.

Conventional slurry casted electrodes cannot stand high loads or be repeatedly flexed or bent without being fractured, which inhibits their use in flexible batteries. Carbon nanotube (CNT) fabric exhibits a paramount mechanical stability and, due to its porosity, can additionally accommodate an active material within its structure. While solution-based protocols cannot achieve conformal coatings of active materials, chemical vapor deposition (CVD) gives a unique opportunity to control and vary the thickness and homogeneity of the coating. Herein, a conformal CVD coating of amorphous iron (III) phosphate (a-FePO 4 , FP) on flexible CNT fabric and its ability to reversibly accommodate large radius Na ions is reported. The freestanding binder-free CNT@FP electrodes exhibit high-rate capabilities and exceptional cycle stabilities with 98% of retention of initial capacity after 100 cycles. Such electrodes additionally demonstrate high mechanical stability under high loads, remarkable bending characteristics, and modulus of toughness (12 MJ m -3 ) exceeding that of Al. The presented concept of flexible CNT@FePO 4 electrodes with high load-bearing characteristics opens new perspectives toward the formation of light-weight, flexible, multifunctional Na-ion battery electrodes based on abundant materials., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Particle-based photodynamic therapy (PPDT) holds great promise in theranostic applications. Herein, we demonstrate that PPDT based on gold nanorods coated with an indocyanine green (ICG)-loaded silica shell allows for the inactivation of the Crohn's disease-associated adherent-invasive Escherichia coli strain LF82 (E. coli LF82) under pulsed laser light irradiation at 810 nm. Fine-tuning of the plasmonic structures together with maximizing the photosensitizer loading onto the nanostructures allowed optimizing the singlet oxygen generation capability and the PPDT efficiency. Using a nanoparticle concentration low enough to suppress photothermal heating effects, 6 log 10 reduction in E. coli LF82 viability could be achieved using gold nanostructures displaying a plasmonic band at 900 nm. An additional modality of nanoparticle-based photoinactivation of E. coli is partly observed, with 3 log 10 reduction of bacterial viability using Au NRs@SiO 2 without ICG, due to the two-photon induced formation of reactive oxygen species. Interaction of the particles with the bacterial surface, responsible for the disruption of the bacterial integrity, together with the generation of moderate quantities of singlet oxygen could account for this behavior.

The potential of gold nanorods post-coated with a 20 nm silica shell loaded with verteporfin (Au NRs@SiO2-VP) as efficient near-infrared nanostructures for photodynamic therapy under continuous wave and pulsed-mode excitation to eradicate a virulent strain of E. coli associated with urinary tract infection is described.

Gold nanoparticles (Au NPs) and reduced graphene oxide (rGO) mediated hyperthermia are the two most widely explored systems used for the photothermal ablation of cancer cells. We show that the photothermal conversion and efficiency of these nanomaterials can be improved not only by combining them into one material, but also by forming bimetallic AuPd embedded on rGO. The AuPd NPs-rGO nanocomposites were prepared by a simple one-step chemical reduction technique using the individual metallic salts, graphene oxide (GO) and ascorbic acid as a green reducing agent. The AuPd NPs-rGO nanocomposites were covalently functionalized with poly(ethylene glycol) (PEG) chains and characterized by high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and UV/Vis spectrophotometry. Covalent attachment of PEG units to the AuPd NPs-rGO nanocomposites greatly improved the solubility and stability of the nanocomposites in biological media and ensured its biocompatibility towards cancer cells such as HeLa cells. The near-infrared photothermal properties of AuPd NPs-rGO-PEG nanocomposites were evaluated using a continuous laser at 800 nm with power densities between 0.5 and 2 W cm -2 . The nanocomposite was successfully used for the in vitro photothermal ablation of HeLa cells. At 1 W cm -2 , the total killing of HeLa cells was achieved through irradiation of AuPd NPs-rGO-PEG nanocomposites incubated cells for 10 min at a particle concentration of 20 μg mL -1 . Such high efficiency was principally assigned to the synergetic effects of rGO and AuPd NPs.

Recent developments in materials science and nanotechnology have propelled the development of a plethora of materials with unique chemical and physical properties for biomedical applications. Graphitic nanomaterials such as carbon nanotubes, fullerenes and, more recently, graphene oxide (GO) and reduced graphene oxide (rGO) have received a great deal of interest in this domain. Besides the exceptional physico-chemical features of these materials, another advantage is that they can be easily produced in good quantities. Moreover, the presence of abundant functional groups on their surface and good biocompatibility make them highly suitable for biomedical applications. Many research groups have utilized GO and rGO nanocargos to effectively deliver insoluble drugs, nucleic acids and other molecules into cells for bioimaging and therapeutic purposes. Gold nanostructures (Au NSs), on the other hand, have also attracted great attention owing to their applications in biomedical fields, organic catalysis, etc. Loading of GO and rGO sheets with Au NSs generates a new class of functional materials with improved properties and thus provides new opportunities in the use of such hybrid materials for catalytic biosensing and biomedical applications. This review article is aimed at providing an insight into the important features of gold-graphene nanocomposites, the current research activities related to the different synthetic routes to produce these nanocomposites, and their potential applications in sensing and biomedical therapy, notably photothermal therapy (PTT).

The development of non-antibiotic based treatments against bacterial infections by Gram-negative uropathogenic E. coli is a complex task. New strategies to treat such infections are thus urgently needed. This report illustrates the development of pegylated reduced graphene oxide nanoparticles (rGO-PEG) and gold nanorods (Au NRs) coated with rGO-PEG (rGO-PEG-Au NRs) for the selective killing of uropathogenic E. coli UTI89. We took advantage of the excellent light absorption properties of rGO-PEG and Au NR particles in the near-infrared (NIR) region to photothermally kill Gram-negative pathogens up to 99% in 10 min by illumination of solutions containing the bacteria. The rGO-PEG-Au NRs demonstrated better photothermal efficiency towards E. coli than rGO-PEG. Targeted killing of E. coli UTI89 could be achieved with rGO-PEG-Au NRs functionalized with multimeric heptyl α-d-mannoside probes. This currently offers a unique biocompatible method for the ablation of pathogens with the opening of probably a new possibility for clinical treatments of patients with urinary infections.

Phenylboronic-acid-modified nanoparticles (NPs) are attracting considerable attention for biological and biomedical applications. We describe here a convenient and general protocol for attaching multiple copies of para-substituted phenylboronic acid moieties onto either iron-oxide-, silica- or diamond-derived NPs. The boronic acid functionalized NPs are all fabricated by first modifying the surface of each particle type with 4-azidobenzoic ester functions. These azide-terminated nanostructures were then reacted with 4-[1-oxo-4-pentyn-1-yl) amino]phenylboronic acid units via a Cu(I) catalyzed Huisgen cycloaddition to furnish, conveniently, the corresponding boronic-acid modified NPs (or "borono-lectins") targeted in this work. The potential of these novel "borono-lectins" as antiviral inhibitors was investigated against the Hepatitis C virus (HCV) exploiting a bioassay that measures the potential of drugs to interfere with the ability of cell-culture-derived JFH1 virus particles to infect healthy hepatocytes. As far as we are aware, this is the first report that describes NP-derived viral entry inhibitors and thus serves as a "proof-of-concept" study. The novel viral entry activity demonstrated, and the fact that the described boronic-acid-functionalized NPs all display much reduced cellular toxicities compared with alternate NPs, sets the stage for their further investigation. The data supports that NP-derived borono-lectins should be pursued as a potential therapeutic strategy for blocking viral entry of HCV.

The synthesis of superparamagnetic nanostructures, especially iron-oxide based nanoparticles (IONPs), with appropriate surface functional groups has been intensively researched for many high-technological applications, including high density data storage, biosensing and biomedicine. In medicine, IONPs are nowadays widely used as contrast agents for magnetic resonance imaging (MRI), in hyperthermia therapy, but are also exploited for drug and gene delivery, detoxification of biological fluids or immunoassays, as they are relatively non-toxic. The use of magnetic particles in vivo requires IONPs to have high magnetization values, diameters below 100 nm with overall narrow size distribution and long time stability in biological fluids. Due to the high surface energies of IONPs agglomeration over time is often encountered. It is thus of prime importance to modify their surface to prevent aggregation and to limit non-specific adsorption of biomolecules onto their surface. Such chemical modifications result in IONPs being well-dispersed and biocompatible, and allow for targeted delivery and specific interactions. The chemical nature of IONPs thus determines not only the overall size of the colloid, but also plays a significant role for in vivo and in vitro applications. This review discusses the different concepts currently used for the surface functionalization and coating of iron oxide nanoparticles. The diverse strategies for the covalent linking of drugs, proteins, enzymes, antibodies, and nucleotides will be discussed and the chemically relevant steps will be explained in detail.