Condensed Matter Systems Exposed to Radiation: Multiscale Theory, Simulations, and Experiment.

This roadmap reviews the new, highly interdisciplinary research field studying the behavior of condensed matter systems exposed to radiation. The Review highlights several recent advances in the field and provides a roadmap for the development of the field over the next decade. Condensed matter systems exposed to radiation can be inorganic, organic, or biological, finite or infinite, composed of different molecular species or materials, exist in different phases, and operate under different thermodynamic conditions. Many of the key phenomena related to the behavior of irradiated systems are very similar and can be understood based on the same fundamental theoretical principles and computational approaches. The multiscale nature of such phenomena requires the quantitative description of the radiation-induced effects occurring at different spatial and temporal scales, ranging from the atomic to the macroscopic, and the interlinks between such descriptions. The multiscale nature of the effects and the similarity of their manifestation in systems of different origins necessarily bring together different disciplines, such as physics, chemistry, biology, materials science, nanoscience, and biomedical research, demonstrating the numerous interlinks and commonalities between them. This research field is highly relevant to many novel and emerging technologies and medical applications.

Shaping the Future of Fuel: Monolithic Metal-Organic Frameworks for High-Density Gas Storage.

The environmental benefits of cleaner, gaseous fuels such as natural gas and hydrogen are widely reported. Yet, practical usage of these fuels is inhibited by current gas storage technology. Here, we discuss the wide-ranging potential of gas-fuels to revolutionize the energy sector and introduce the limitations of current storage technology that prevent this transition from taking place. The practical capabilities of adsorptive gas storage using porous, crystalline metal-organic frameworks (MOFs) are examined with regard to recent benchmark results and ultimate storage targets in this field. In particular, the industrial limitations of typically powdered MOFs are discussed while recent breakthroughs in MOF processing are highlighted. We offer our perspective on the future of practical, rather than purely academic, MOF developments in the increasingly critical field of environmental fuel storage.

Reactions of Trimethylaluminium: Modelling the Chemical Degradation of Synthetic Lubricants.

In investigating and seeking to mimic the reactivity of trimethylaluminium (TMA) with synthetic, ester-based lubricating oils, the reaction of methyl propionate 1 was explored with 1, 2 and 3 equivalents of the organoaluminium reagent. Spectroscopic analysis points to the formation of the adduct 1(TMA) accompanied only by the low level 1:1 production of Me2 AlOCEtMe2 2 and Me2 AlOMe 3 when an equimolar amount of TMA is applied. The deployment of excess TMA favours reaction to give 2 and 3 over 1(TMA) adduct formation and spectroscopy reveals that in hydrocarbon solution substitution product 2 traps unreacted TMA to yield 2(TMA). The 1 H NMR spectroscopic observation of two Al-Me signals not attributable to free TMA and in the ratio 1:4 suggests the formation of a previously only postulated, symmetrical metallacycle in Me4 Al2 (µ2 -Me)(µ2 -OCEtMe2 ). In the presence of 3, 2(TMA) undergoes thermally induced exchange to yield Me4 Al2 (µ2 -OMe)(µ2 -OCEtMe2 ) 4 and TMA. The reaction of methyl phenylacetate 5 with TMA allows isolation of the crystalline product Me2 AlOCBnMe2 (TMA) 6(TMA), which allows the first observation of the Me4 Al2 (µ2 -Me)(µ2 -OR) motif in the solid state. Distances of 2.133(3) Š(Al-Mebridging ) and 1.951 Š(mean Al-Meterminal ) are recorded. The abstraction of TMA from 6(TMA) by the introduction of Et2 O has yielded 6, which exists as a dimer.

Multicomponent signal unmixing from nanoheterostructures: overcoming the traditional challenges of nanoscale X-ray analysis via machine learning.

The chemical composition of core-shell nanoparticle clusters have been determined through principal component analysis (PCA) and independent component analysis (ICA) of an energy-dispersive X-ray (EDX) spectrum image (SI) acquired in a scanning transmission electron microscope (STEM). The method blindly decomposes the SI into three components, which are found to accurately represent the isolated and unmixed X-ray signals originating from the supporting carbon film, the shell, and the bimetallic core. The composition of the latter is verified by and is in excellent agreement with the separate quantification of bare bimetallic seed nanoparticles.

Structural effects in lithiocuprate chemistry: the elucidation of reactive pentametallic complexes.

TMPLi (TMP=2,2,6,6-tetramethylpiperidide) reacts with Cu(I) salts in the presence of Et2O to give the dimers [{(TMP)2Cu(X)Li2 (OEt2)}2] (X=CN, halide). In contrast, the use of DMPLi (DMP=cis-2,6-dimethylpiperidide) gives an unprecedented structural motif; [{(DMP)2CuLi(OEt2)}2LiX] (X=halide). This formulation suggests a hitherto unexplored route to the in situ formation of Gilman-type bases that are of proven reactivity in directed ortho cupration.

Enhancing Drug Delivery Efficacy Through Bilayer Coating of Zirconium-Based Metal-Organic Frameworks: Sustained Release and Improved Chemical Stability and Cellular Uptake for Cancer Therapy.

The development of nanoparticle (NP)-based drug carriers has presented an exciting opportunity to address challenges in oncology. Among the 100,000 available possibilities, zirconium-based metal-organic frameworks (MOFs) have emerged as promising candidates in biomedical applications. Zr-MOFs can be easily synthesized as small-size NPs compatible with intravenous injection, whereas the ease of decorating their external surfaces with functional groups allows for targeted treatment. Despite these benefits, Zr-MOFs suffer degradation and aggregation in real, in vivo conditions, whereas the loaded drugs will suffer the burst effect-i.e., the fast release of drugs in less than 48 h. To tackle these issues, we developed a simple but effective bilayer coating strategy in a generic, two-step process. In this work, bilayer-coated MOF NU-901 remained well dispersed in biologically relevant fluids such as buffers and cell growth media. Additionally, the coating enhances the long-term stability of drug-loaded MOFs in water by simultaneously preventing sustained leakage of the drug and aggregation of the MOF particles. We evaluated our materials for the encapsulation and transport of pemetrexed, the standard-of-care chemotherapy in mesothelioma. The bilayer coating allowed for a slowed release of pemetrexed over 7 days, superior to the typical 48 h release found in bare MOFs. This slow release and the related performance were studied in vitro using both A549 lung cancer and 3T mesothelioma cells. Using high-resolution microscopy, we found the successful uptake of bilayer-coated MOFs by the cells with an accumulation in the lysosomes. The pemetrex-loaded NU-901 was indeed cytotoxic to 3T and A549 cancer cells. Finally, we demonstrated the general approach by extending the coating strategy using two additional lipids and four surfactants. This research highlights how a simple yet effective bilayer coating provides new insights into the design of promising MOF-based drug delivery systems.

Manipulating morphology and composition in colloidal heterometallic nanopods and nanodendrites.

Branched Pt nanoparticles represent an exciting class of nanomaterials with high surface areas suitable for applications in electrocatalysis. Introducing a second metal can enhance performance and reduce cost. External factors such as capping agents and temperature have been used to offer insights into nanopod formation and to encourage their kinetic evolution. More recently, nanodendrites have been reported, though synthesis has generally been empirical; making controlled variation of morphology while maintaining bimetallic composition an elusive target. We report the combination of Pt with Fe under a range of conditions, yielding individually bimetallic nanoparticles whose construction sheds new light on nanopod and/or nanodendrite formation. Fine control of metal precursor reduction through modulating capping agents, reagents, and temperature initially directs nanopod synthesis. Morphology control is retained while composition is then varied from Pt-rich to Pt-poor. Additionally, conditions are identified that promote the collision-based branching of nanopod arms. This allows synthesis to be redirected for the selective growth of compositionally controlled nanodendrites in predictable fashion.

Lithiated tertiary carbanions display variable coordination modes: evidence from DFT and NMR studies.

Density functional calculations reveal that, whereas the reaction of 2-propyl-N,N-diisopropylbenzamide (6) with tBuLi in the presence of potentially tridentate donor ligands may result in lateral deprotonation of 6, the behavior of the Lewis base is non-trivial. The ability of N and O donor centers in the co-solvent to resist Li(+) coordination is found to be synonymous with interaction of lithium with the formally deprotonated carbanion center. Low-energy structures have been identified whose predicted (1)H and (13)C NMR spectroscopic shifts are in excellent agreement with experiment. Reaction of 2-isopropyl-N,N-diisopropylbenzamide (5) with tBuLi in the presence of bidentate Lewis base N,N,N',N'-tetramethylethylenediamine (TMEDA) yields material that is suggested by NMR spectroscopy to be laterally deprotonated and to have the formulation 5-Li(l)·TMEDA. In spite of the tertiary aliphatic group at the 2-position in 5, X-ray crystallography reveals that the crystalline material isolated from the treatment of 5/(-)-sparteine with tBuLi is a lateral lithiate in which amide coordination and solvation by bidentate Lewis base results in the Li(+) ion interacting with the deprotonated α-C of the 2-iPr group (2.483(8) Å). The tertiary carbanion center remains essentially flat and the adjacent aromatic system is highly distorted. The use of a chiral co-solvent results in two diastereomeric conformers, and their direct observation in solution suggests that interconversion is slow on the NMR timescale.

New Cu-based catalysts supported on TiO2 films for Ullmann S(N)Ar-type C-O coupling reactions.

New routes for the preparation of highly active TiO(2)-supported Cu and CuZn catalysts have been developed for C-O coupling reactions. Slurries of a titania precursor were dip-coated onto glass beads to obtain either structured mesoporous or non-porous titania thin films. The Cu and CuZn nanoparticles, synthesized using a reduction by solvent method, were deposited onto calcined films to obtain a Cu loading of 2 wt%. The catalysts were characterized by inductively coupled plasma (ICP) spectroscopy, temperature-programmed oxidation/reduction (TPO/TPR) techniques, (63)Cu nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction (XRD), scanning and transmission electron microscopy (S/TEM-EDX) and X-ray photo-electron spectroscopy (XPS). The activity and stability of the catalysts obtained have been studied in the C-O Ullmann coupling of 4-chloropyridine and potassium phenolate. The titania-supported nanoparticles retained catalyst activity for up to 12 h. However, catalyst deactivation was observed for longer operation times due to oxidation of the Cu nanoparticles. The oxidation rate could be significantly reduced over the CuZn/TiO(2) catalytic films due to the presence of Zn. The 4-phenoxypyridine yield was 64% on the Cu/nonporous TiO(2) at 120 °C. The highest product yield of 84% was obtained on the Cu/mesoporous TiO(2) at 140 °C, corresponding to an initial reaction rate of 104 mmol g(cat) (-1) s(-1). The activation energy on the Cu/mesoporous TiO(2) catalyst was found to be (144±5) kJ mol(-1), which is close to the value obtained for the reaction over unsupported CuZn nanoparticles (123±3 kJ mol(-1)) and almost twice the value observed over the catalysts deposited onto the non-porous TiO(2) support (75±2 kJ mol(-1)).

On the control of secondary carbanion structure utilising ligand effects during directed metallation.

N,N-Diisopropyl-2-propylbenzamide 6-H undergoes lateral deprotonation by t-BuLi in the presence of the Lewis base PMDTA (N,N,N',N″,N″-pentamethyldiethylenetriamine) to give a benzyllithium 6-Li(l)·PMDTA that incorporates a trigonal planar secondary carbanion. In the solid state, the amide directing group and the PMDTA additive work together to abstract the metal ion from the deprotonated α-C of the propyl group (4.107(4) Å). A short distance of 1.376(3) Å is observed between the deprotonated carbon centre and a planar aromatic system that shows a pattern of bond lengths which contrasts with that reported for related tertiary carbanion systems. Analogous benzylic deprotonation is seen if 6-H is treated with t-BuLi in the presence of diglyme to give 6-Li(l)·DGME. X-ray crystallography now shows that the metal ion more closely approaches the tertiary carbanion (2.418(6) Å) but that the planarity of the deprotonated carbon centre and the bonding pattern in the organic anion seen in the PMDTA complex are retained. DFT analysis corroborates both the short distance between aromatic ring and carbanion centre and the unperturbed nature of aromaticity in 6-Li(l)·L (L = Lewis base). The observation of two structure-types for the carbanion in solution is explained theoretically and by NMR spectroscopy in terms of cis and trans isomerism imparted by partial double bond character in the arene-(α-C) bond.

Visible light photocatalysts from low-grade iron ore: the environmentally benign production of magnetite/carbon (Fe3O4/C) nanocomposites.

Magnetite (Fe3O4) nanoparticles coated with dextrose and gluconic acid possessing both super-paramagnetism and excellent optical properties have been productively synthesized through a straightforward, efficient and cost-efficient hydrothermal reduction route using Fe3+ as sole metal precursor acquired from accumulated iron ore tailings-a mining waste that usually represents a major environmental threat. Fe3O4/C nanocomposites were fully elucidated by FEGSEM and TEM, revealing a combination of platelets (<1 µm) capped by particles (<10 nm) and magnetite which was verified by XPS, which demonstrated also oxygen deficiency. A dextrose/gluconic acid coating was elucidated by Fourier transform-infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). The Fe3O4/C nanocomposites were found to be superparamagnetic at room temperature. Meanwhile, their optical properties were investigated by UV-visible diffuse reflectance spectroscopy (UV-vis DRS) and photoluminescence (PL) spectroscopy; an Eg of 1.86 eV was determined, and emissions at 612 and 650 nm (ex. 250 nm) were consistent with the XPS identification of oxygen vacancies. The efficacy of the as-synthesized magnetically recoverable magnetite/carbon (Fe3O4/C) nanocomposites has been exhibited in the photocatalytic degradation of the toxic textile (industrial) dye bodactive red BNC-BS.

Ligand effects in the formation of tertiary carbanions from substituted tertiary aromatic amides.

Reaction of 2-isopropyl-(N,N-diisopropyl)-benzamide 5 with tBuLi in ether results in ortho deprotonation and the formation of a hemisolvate based on a tetranuclear dimer of (5-Li(o))(2)⋅Et(2)O. The solid-state structure exhibits a dimer core in which the amide oxygen atoms fail to stabilize the metal ions but are instead available for interaction with two metalated monomers that reside peripheral to the core. Reaction of 5 with tBuLi in the presence of the tridentate Lewis base PMDTA (N,N,N',N'',N''-pentamethyldiethylenetriamine) takes a different course. In spite of the tertiary aliphatic group at the 2-position in 5, X-ray crystallography revealed that a remarkable benzylic (lateral) deprotonation had occurred, giving the tertiary benzyllithium 5-Li(l)⋅PMDTA. The solid-state structure reveals that amide coordination and solvation by PMDTA combine to distance the Li(+) ion from the deprotonated α-C of the 2-iPr group (3.859(4) Å), thus giving an essentially flat tertiary carbanion and a highly distorted aromatic system. DFT analysis suggests that the metal ion resides closer to the carbanion center in solution. In line with this, the same (benzylic) deprotonation is noted if the reaction is attempted in the presence of tridentate diglyme, with X-ray crystallography revealing that the metal is now closer to the tertiary carbanion (2.497(4) Å). Electrophilic quenches of lithiated 5 have allowed, for the first time, the formation of quaternary benzylic substituents by lateral lithiation.

Deprotonative metalation of chloro- and bromopyridines using amido-based bimetallic species and regioselectivity-computed CH acidity relationships.

A series of chloro- and bromopyridines have been deprotometalated by using a range of 2,2,6,6-tetramethylpiperidino-based mixed lithium-metal combinations. Whereas lithium-zinc and lithium-cadmium bases afforded different mono- and diiodides after subsequent interception with iodine, complete regioselectivities were observed with the corresponding lithium-copper combination, as demonstrated by subsequent trapping with benzoyl chlorides. The obtained selectivities have been discussed in light of the CH acidities of the substrates, determined both in the gas phase and as a solution in THF by using the DFT B3LYP method.

Nanoparticulate PdZn--pathways towards the synthetic control of nanosurface properties.

This paper reports an in-depth structural investigation of PdZn nanoparticulates prepared over an entire compositional range. By using a combination of HRTEM, ICP-OES, EDX and XPS alongside PXRD, we are able to show how a liquid-type reduction process can be exploited to target different PdZn bimetallic structures while maintaining reproducibly narrow particle size distributions and average particle diameters of approximately 3 nm. Samples have been further analyzed by quantitative phase analysis of the Rietveld refined diffraction data, providing indications as to how variations in specific surface compositions are obtained when Zn is used as the alloying metal. The influence of nanolattice strain is investigated by geometric analysis of TEM data. Results suggest, in conjunction with previously published catalytic data, how different compositions of this specific bimetallic system may be exploited in catalytic processes to control substrate/product affinity. We thus demonstrate a new and simplified approach to PdZn bimetallics, which may offer novel perspectives for applications in industrial catalysis.

A reusable catalyst based on CuO hexapods and a CuO-Ag composite for the highly efficient reduction of nitrophenols.

The enormous and urgent need to explore cost-effective catalysts with high efficiency has always been at the forefront of environmental protection and remediation research. This work develops a novel strategy for the fabrication of reusable CuO-based non-noble metal nanomaterials as high-efficiency catalysts. We report a facile and eco-friendly synthesis of CuO hexapods and CuO-Ag composite using uric acid as a reductant and protectant. Both exhibited high catalytic activity in the hydrogenation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by sodium borohydride (NaBH4), with the CuO-Ag composite showing superior catalytic performance. Notably, the highest turnover frequency of CuO-Ag reached 7.97 × 10-2 s-1, which was much higher than numerous noble-metal nanomaterials. In addition, CuO hexapods and CuO-Ag composite were also shown to act as highly efficient and recyclable catalysts in the degeneration of 4-NP. Both CuO hexapods and the CuO-Ag composite exhibited outstanding catalytic durability, with no significant loss of activity over more than 10 cycles in the hydrogenation of 4-NP.

Lipshutz-type bis(amido)argentates for directed ortho argentation.

Bis(amido)argentate (TMP)2Ag(CN)Li2 (3, TMP-Ag-ate; TMP = 2,2,6,6-tetramethylpiperidido) was designed as a tool for chemoselective aromatic functionalization via unprecedented directed ortho argentation (DoAg). X-Ray crystallographic analysis showed that 3 takes a structure analogous to that of the corresponding Lipshutz cuprate. DoAg with this TMP-Ag-ate afforded multifunctional aromatics in high yields in processes that exhibited high chemoselectivity and compatibility with a wide range of functional groups. These included organometallics- and transition metal-susceptible substituents such as methyl ester, aldehyde, vinyl, iodo, (trifluoromethanesulfonyl)oxy and nitro groups. The arylargentates displayed good reactivity with various electrophiles. Chalcogen (S, Se, and Te) installation and azo coupling reactions also proceeded efficiently.

Capillary microreactors wall-coated with mesoporous titania thin film catalyst supports.

A new method for catalyst deposition on the inner walls of capillary microreactors is proposed which allows exact control of the coating thickness, pore size of the support, metal particle size, and metal loading. The wall-coated microreactors have been tested in a selective hydrogenation reaction. Activity and selectivity reach values close to those obtained with a homogeneous Pd catalyst. The catalyst activity was stable for a period of 1000 h time-on-stream.

A simple one-step synthetic route to access a range of metal-doped polyoxovanadate clusters.

VO(OiPr)3 is a useful precursor for the synthesis of a range of metal-doped polyoxovanadate (POV) cage compounds, its reactions with hydrated metal salts providing a route to arrangements containing Bi and other main group metals, transition metals and lanthanides. The new POV compounds [Bi2(DMSO)6V12O33Br]2[M(DMSO)6] (2Br-M, M = CoII, NiII, CuII, ZnII) [Bi2(DMSO)6V12O33Cl]2[Ca(DMSO)x]·yDMSO (2Cl-Ca), [Bi2(DMSO)6V12O33Cl]2[LnCl(DMSO)7] (2Cl-Ln, Ln = LaIII, CeIII, EuIII), [Bi2(DMSO)6V10O28F2]3[Bi(DMSO)5]2 (3), [V12O32(DMSO)][Gd(NO3)(DMSO)5.5]2 (4) and [Ln(DMSO)4V12O32Cl][LnCl(DMSO)7] (5Cl-Ln, Ln = CeIII, EuIII) have been structurally characterised, and their properties studied using UV-Vis spectroscopy and cyclic voltammetry. Drop-casting these compounds onto fluorine-doped tin oxide followed by calcination provides a simple approach to thin films of metal-doped BiVO4 or LnVO4, depending on the composition of the cage precursor. The applications of the BiVO4 films as photoanodes for water oxidation is explored, with transition metal doping of BiVO4 improving the activity (∼1.8-2.4 times the photocurrent density of undoped BiVO4 at 1.23 V vs. RHE) while lanthanide or Ca-doping is detrimental.

A new route for the efficient metalation of unfunctionalized aromatics.

The synthesis and isolation of a novel bimetallic species formed by reacting two equivalents of TMPLi with CuCl in the presence of Et2O are reported. X-ray crystallography reveals the Et2O-free tetranuclear aggregate (TMPCu)2(TMPLi)2 1, which formally results from the catenation of dimers of TMPLi and TMPCu. NMR spectroscopy confirms that, upon dissolution in hydrocarbon media, the crystals fail to form a conventional Gilman cuprate dimer. Instead they exhibit a spectrum which is consistent with that recently proposed for an isomer of dimeric Gilman cuprate. Moreover, while pre-isolated Gilman cuprate is inert to benzene solvent, this new isomer smoothly affects aromatic deprotonation to give mainly Ph(TMP)3Cu2Li2 3, which is formally a heterodimer of Gilman cuprate TMPCu(µ-TMP)Li 2 and PhCu(µ-TMP)Li 4. Attempts to synthesise 3 through explicit combination of pre-isolated 2 and 4 were successful; additionally, this permitted the preparation of Ph(TMP)3Cu3Li 5 and Ph(TMP)3CuLi3 7 when 4 was combined in 1 : 2 ratios with TMPCu or TMPLi, respectively. 5 was characterised as metallacyclic in the solid-state, its structural features resembling those in 3 but with reduced Li-π interactions. It also proved possible to perform Cu/Li exchange on 5 (using t BuOCu) to give a novel mixed organo(amido)copper species Ph(TMP)3Cu4 6. Remarkably, the unprecedented reactivity of 1 towards benzene is reproduced by heating a 1 : 1 mixture of TMPLi and TMPCu in the same solvent; this gives predominantly 3. On the other hand, mixtures which are rich in either Cu or Li can lead to the selective in situ formation of 5 or 7. Though crystallographic data on 7 could not be obtained, DFT calculations accurately corroborated the observed structures of 3 and 5 and could be used to support 7 having the same structure type, albeit with enhanced Li-π interactions. This was consistent with NMR spectroscopic data. However, in contrast to 3 and 5, for which 2D NMR spectroscopy indicated only conformational changes, 7 was additionally found to exhibit fluxionality in a manner consistent with a dissociative process.

Comprehensive Experimental and Theoretical Study of the CO + NO Reaction Catalyzed by Au/Ni Nanoparticles.

The catalytic and structural properties of five different nanoparticle catalysts with varying Au/Ni composition were studied by six different methods, including in situ X-ray absorption spectroscopy and density functional theory (DFT) calculations. The as-prepared materials contained substantial amounts of residual capping agent arising from the commonly used synthetic procedure. Thorough removal of this material by oxidation was essential for the acquisition of valid catalytic data. All catalysts were highly selective toward N2 formation, with 50-50 Au:Ni material being best of all. In situ X-ray absorption near edge structure spectroscopy showed that although Au acted to moderate the oxidation state of Ni, there was no clear correlation between catalytic activity and nickel oxidation state. However, in situ extended X-ray absorption fine structure spectroscopy showed a good correlation between Au-Ni coordination number (highest for Ni50Au50) and catalytic activity. Importantly, these measurements also demonstrated substantial and reversible Au/Ni intermixing as a function of temperature between 550 °C (reaction temperature) and 150 °C, underlining the importance of in situ methods to the correct interpretation of reaction data. DFT calculations on smooth, stepped, monometallic and bimetallic surfaces showed that N + N recombination rather than NO dissociation was always rate-determining and that the activation barrier to recombination reaction decreased with increased Au content, thus accounting for the experimental observations. Across the entire composition range, the oxidation state of Ni did not correlate with activity, in disagreement with earlier work, and theory showed that NiO itself should be catalytically inert. Au-Ni interactions were of paramount importance in promoting N + N recombination, the rate-limiting step.