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With machine learning being a popular topic in current computational materials science literature, creating representations for compounds has become common place. These representations are rarely compared, as evaluating their performance - and the performance of the algorithms that they are used with - is non-trivial. With many materials datasets containing bias and skew caused by the research process, leave one cluster out cross validation (LOCO-CV) has been introduced as a way of measuring the performance of an algorithm in predicting previously unseen groups of materials. This raises the question of the impact, and control, of the range of cluster sizes on the LOCO-CV measurement outcomes. We present a thorough comparison between composition-based representations, and investigate how kernel approximation functions can be used to better separate data to enhance LOCO-CV applications. We find that domain knowledge does not improve machine learning performance in most tasks tested, with band gap prediction being the notable exception. We also find that the radial basis function improves the linear separability of chemical datasets in all 10 datasets tested and provide a framework for the application of this function in the LOCO-CV process to improve the outcome of LOCO-CV measurements regardless of machine learning algorithm, choice of metric, and choice of compound representation. We recommend kernelised LOCO-CV as a training paradigm for those looking to measure the extrapolatory power of an algorithm on materials data., Comment: 16 pages including references, 9 figures

High-performance and stability for protonic ceramic fuel cell cathode applications are realised in a self-assembled nanocomposite material Ba0.5Sr0.5(Co0.7Fe0.3)0.6875W0.3125O3−δ (BSCFW) through interplay of single and double perovskite phases.

We apply molecular simulations to screen a database of reported metal-organic framework structures from the computation-ready, experimental (CoRE) MOF database to identify materials potentially capable of separating propane and propene by diffusion. We report a screening workflow that uses descriptor analysis, conventional molecular dynamics (MD), and Nudged Elastic Band (NEB) energy barrier calculations at both classical force field and Density Functional Theory (DFT) levels. For the first time, the effects of framework flexibility on guest transport properties were fully considered in a screening process and led to the identification of candidate MOFs. The hits identified by this proof-of-concept workflow include ZIF-8 and ZIF-67 previously shown to have large differences in propane and propene diffusivities as well as two other materials that have not been tested experimentally yet. This work emphasises the importance of taking into account framework flexibility when studying guest transport in porous materials, demonstrates the potential of the data-driven identification of high-performance materials and highlights the ways of improving the predictive power of the screening workflow.

We present a new method of evolving crystal structures for crystal structure prediction. The method of chemically directed structure evolution uses chemical models to quantify the environment of atoms and vacancy sites in a crystal structure, with that information used to inform how to modify the structure to make a move on the potential energy surface. We have developed a method of chemically directed swapping, where we swap atoms in the least favourable chemical environments. This method has been implemented in the crystal structure prediction code ChemDASH (Chemically Directed Atom Swap Hopping), which explores the potential energy surface using a basin-hopping approach, and evaluates chemical environments using either the bond valence sum or electrostatic site potential. ChemDASH has a variety of methods of initialising structures, optimising structures, and swapping atoms. This gives ChemDASH the flexibility to be applied to a wide range of systems. We used ChemDASH to examine the effectiveness of the directed swapping method. Directed swapping finds the ground states of TiO2 and SrTiO3 faster than random (non-directed) swapping, but is less effective than random swapping for Y2Ti2O7.

Nanoparticle contrast agents are useful tools to label stem cells and monitor the in vivo bio-distribution of labeled cells in pre-clinical models of disease. In this context, understanding the in vivo fate of the particles after injection of labelled cells is important for their eventual clinical use as well as for the interpretation of imaging results. We examined how the formulation of superparamagnetic iron oxide nanoparticles (SPIONs) impacts the labelling efficiency, magnetic characteristics and fate of the particles by comparing individual SPIONs with polyelectrolyte multilayer capsules containing SPIONs. At low labelling concentration, encapsulated SPIONs served as an efficient labelling agent for stem cells. The bio-distribution after intra-cardiac injection of labelled cells was monitored longitudinally by MRI and as an endpoint by inductively coupled plasma-optical emission spectrometry. The results suggest that, after being released from labelled cells after cell death, both formulations of particles are initially stored in liver and spleen and are not completely cleared from these organs 2 weeks post-injection.

Highly dense CaMn1-xRexO3 (0 ≤ x ≤ 0.04) samples were prepared by solid-state synthesis. The effect of Re doping was assessed by the characterisation of crystal structure, oxygen content, and electrical and thermal transport properties. The oxidation state of the substituted Re was determined by X-ray absorption near edge spectra to be Re7+, and led to expansion of the lattice and an increase in electron carrier concentration due to the formation of Mn3+. The thermal behaviour of the electrical conductivity and the thermopower over a wide temperature range allowed identification of different conduction mechanisms: (1) below 110 K, 3D variable range hopping, (2) between 110 and 650 K, small polaron transport, and (3) above 650 K, activation of carriers over a mobility edge. Evaluation of the power factor expected for different dopant oxidation states as a function of dopant concentration shows that the doping strategy using a heavy heptavalent ion allows accessibility of the peak power factor at lower dopant concentrations, lowering the amount of non-ionised impurities, and therefore improves the electronic substitution efficiency, the ratio of activated carriers over the nominal doping concentration, compared to previously studied dopants. An increased power factor and a reduced lattice thermal conductivity are obtained with a peak figure of merit ZT = 0.16(3) at 947 K for CaMn0.98Re0.02O3. This is an approximately two-fold increase compared to undoped CaMnO3, and is comparable to the highest values reported for highly dense B-site doped CaMnO3.

Phonon-glass electron-crystal (PGEC) behaviour is realised in La0.5Na0.5Ti1-xNbxO3 thermoelectric oxides. The vibrational disorder imposed by the presence of both La3+ and Na+ cations on the A site of the ABO(3) perovskite oxide La0.5Na0.5TiO3 produces a phononglass with a thermal conductivity, kappa, 80% lower than that of SrTiO3 at room temperature. Unlike other state-of-the-art thermoelectric oxides, where there is strong coupling of kappa to the electronic power factor, the electronic transport of these materials can be optimised independently of the thermal transport through cation substitution at the octahedral B site. The low kappa of the phonon-glass parent is retained across the La0.5Na0.5Ti1-xNbxO3 series without disrupting the electronic conductivity, affording PGEC behaviour in oxides.

The production of cyclopentanone derivatives from 5-hydroxymethylfurfural (HMF) using non-noble metal based catalysts is reported for the first time. Five different mixed oxides containing Ni, Cu, Co, Zn and Mg phases on an Al-rich amorphous support were prepared and characterised (XRD, ICP, SEM, TEM, H2-TPR, NH3/CO2-TPD and N2 sorption). The synthesised materials resulted in well-dispersed high metal loadings in a mesoporous network, exhibiting acid/base properties. The catalytic performance was tested in a batch stirred reactor under H2 pressure (20–50 bar) in the range T = 140–180 °C. The Cu–Al2O3 and the Co–Al2O3 catalysts showed a highly selective production of 3-hydroxymethylcyclopentanone (HCPN, 86%) and 3-hydroxymethylcyclopentanol (HCPL, 94%), respectively. A plausible reaction mechanism is proposed, clarifying the role of the reduced metal phases and the acid/basic sites on the main conversion pathways. Both Cu–Al2O3 and Co–Al2O3 catalysts showed a loss of activity after the first run, which can be reversed by a regeneration treatment. The results establish an efficient catalytic route for the production of the diol HCPL (reported for the first time) and the ketone HCPN from bio-derived HMF over 3d transition metals based catalysts in an environmental friendly medium such as water.

Tracking stem cells in vivo using non-invasive techniques is critical to evaluate the efficacy and safety of stem cell therapies. Superparamagnetic iron oxide nanoparticles (SPIONs) enable cells to be tracked using magnetic resonance imaging (MRI), but to obtain detectable signal cells need to be labelled with a sufficient amount of iron oxide. For the majority of SPIONs, this can only be obtained with the use of transfection agents, which can adversely affect cell health. Here, we have synthesised a library of dextran-based polymer coated SPIONs with varying surface charge from -1.5 mV to +18.2 mV via a co-precipitation approach and investigated their ability to be directly internalised by stem cells without the need for transfection agents. The SPIONs were colloidally stable in physiological solutions. The crystalline phase of the particles was confirmed with powder X-ray diffraction and their magnetic properties were characterised using SQUID magnetometry and magnetic resonance. Increased surface charge led to six-fold increase in uptake of particles into stem cells and higher MRI contrast, with negligible change in cell viability. Cell tracking velocimetry was shown to be a more accurate method for predicting MRI contrast of stem cells compared to measuring iron oxide uptake through conventional bulk iron quantification.

The most expanded fcc-structured alkali fulleride, Cs3C60, is a Mott insulator at ambient pressure because of the weak overlap between the frontier t1u molecular orbitals of the C603− anions. It has a severely disordered antiferromagnetic ground state that becomes a superconductor with a high critical temperature, Tc of 35 K upon compression. The effect of the localised t1u3 electronic configuration on the properties of the material is not well-understood. Here we study the relationship between the intrinsic crystallographic C603− orientational disorder and the molecular Jahn–Teller (JT) effect dynamics in the Mott insulating state. The high-resolution 13C magic-angle-spinning (MAS) NMR spectrum at room temperature comprises three peaks in the intensity ratio 1:2:2 consistent with the presence of three crystallographically-inequivalent carbon sites in the fcc unit cell and revealing that the JT-effect dynamics are fast on the NMR time-scale of 10−5 s despite the presence of the frozen-in C603− merohedral disorder disclosed by the 133Cs MAS NMR fine splitting of the tetrahedral and octahedral 133Cs resonances. Cooling to sub-liquid-nitrogen temperatures leads to severe broadening of both the 13C and 133Cs MAS NMR multiplets, which provides the signature of an increased number of inequivalent 13C and 133Cs sites. This is attributed to the freezing out of the C603− JT dynamics and the development of a t1u electronic orbital glass state guided by the merohedral disorder of the fcc structure. The observation of the dynamic and static JT effect in the Mott insulating state of the metrically cubic but merohedrally disordered Cs3C60 fulleride in different temperature ranges reveals the intimate relation between charge localization, magnetic ground state, lifting of electronic degeneracy, and orientational disorder in these strongly-correlated systems.

The Extended Module Materials Assembly computational method for structure solution and prediction has been implemented for close-packed lattices. Exploring the family of B-site deficient materials in hexagonal perovskite barium cobalt niobates, it is found that the EMMA procedure returns the experimental structures as the most stable for the known compositions of Ba3CoNb2O9, Ba5Nb4O15 and Ba8CoNb6O24. The unknown compositions Ba11Co2Nb8O33 and Ba13CoNb10O39, having longer stacking sequences, are predicted to form as intergrowths of Ba3CoNb2O9 and Ba5Nb4O15, and are found to have similar stability to pure Ba3CoNb2O9 and Ba5Nb4O15, indicating that it is likely they can be synthesised.

A porphyrin-based metal-organic framework is shown to be structurally stable towards acid loading using either hydrochloric or formic acid. The capacity of this material as an ammonia sorbent was analysed using micro-breakthrough experiments in both dry and humid ammonia flows. The acid loaded material exhibited excellent uptake in comparison with the parent MOF.

The (AO)(ABO3)n Ruddlesden-Popper structure is an archetypal complex oxide consisting of two distinct structural units, an (AO) rock salt layer separating an n-octahedra thick perovskite block. Conventional high-temperature oxide synthesis methods cannot access members with n > 3, but low-temperature layer-by-layer thin film methods allow the preparation of materials with thicker perovskite blocks, exploiting high surface mobility and lattice matching with the substrate. This paper describes the growth of an n = 6 member CaO[(CSMO)2(LCMO)2 (CSMO)2] in which the six unit cell perovskite block is sub-divided into two central La0.67Ca0.33MnO3 (LCMO) and two terminal Ca0.85Sm0.15MnO3 (CSMO) layers to allow stabilization of the rock salt layer and variation of the transition metal charge.

A polycrystalline sample of Sr1.2Nd0.8Mn0.6Rh0.4O4 has been synthesised and characterised by neutron diffraction, dc magnetometry, muon spectroscopy and magnetotransport measurements. Ir is an n = 1 member of the Ruddlesden-Popper (RP) An + 1BnO3n + 1 family, having tetragonal (I4/mmm) symmetry [a = 3.86418(6), c = 12.4414(2) Å]. Rh and Mn cations are disordered over the six-coordinate sites within the perovskite layers of the RP structure and the A sites are occupied by a disordered distribution of Nd and Sr. In contrast to the analogous compound Sr1.2La 0.8Mn0.6Rh0.4O4, which showed long range ferromagnetic ordering in an applied field ar 2 K, a spin-glass transition was observed ar 16 K for the Nd-containing compound. No long range magnetic order was observed ar 2 K. A maximum magnetoresistance of ∼ 30% in a 140 kOe field was found at 125 K.

The layered semiconductor Pt-HCa(2)Nb(3)O(10) can catalyze room temperature air oxidation of methyl orange. It is also more effective than Pt-WO(3) in catalyzing reaction of methanol with air. Pt-HCa(2)Nb(3)O(10) could find wide application as a mild oxidizing catalyst.

Traditional solid state synthetic methods were used to prepare a polycrystalline sample of the n = 3 Ruddlesden-Popper phase Ca4Mn2TiO9.93. The crystal structure (space group Pbca, a = 5.31411(5), b = 5.31148(5), c = 26.9138(2)Angstrom) was determined by the simultaneous analysis of neutron and X-ray diffraction data, with near-edge anomalous scattering being used to provide contrast between Mn and Ti cations. The latter show a small preference for the octahedral sites at the centre of the three-layer perovskite blocks within the structure. Neutron diffraction data collected at 5 K show no evidence for long-range magnetic ordering, although an enhanced magnetisation with a weak remanence is observed at low temperature; this is ascribed to the presence of antisymmetric exchange interactions. Ca4Mn2TiO9.93 is a semiconductor with a temperature-dependent activation energy of similar to 100 meV. Only weak (rho (B)/rho (0) > 0.9 in 14 T at 75 K) magnetoresistance was observed.

A series of novel double perovskites La1 + xA1 − xInMnO6 − δ (A = Sr, Ba) has been prepared and the room temperature crystal structures have been refined using X-ray and neutron powder diffraction. In all cases the B-site is occupied by a disordered arrangement of In3+ and Mn3+/4+ cations. However, whereas La1 + xBa1 − xInMnO6 − δ exhibits two octahedral tilts and exists in a body-centred cell, space group Imma, La1 + xSr1 − xInMnO6 − δ adopts the three-tilt GdFeO3 structure and has a primitive orthorhombic structure, space group Pnma. Magnetic susceptibility data show that all the compositions synthesised exhibit a spin glass freezing transition at ∼8 K. A negative magnetoresistance Δρ/ρ0 = 10.5% was measured at 164 K in a field of 14 T.

Cs4C60 is reported as a pure phase for the first time, using low-temperature synthesis. It adopts an orthorhombic distortion of the body-centred tetragonal (bct) A4C60 structure found for K4C60 and Rb4C60 , due to the orientational ordering of the C604– anions with the 6:6 bonds directed along the orthorhombic b-axis. The caesium cations occupy two distinct distorted tetrahedral sites, producing the orientational order to avoid close contact with the five-membered rings of neighbouring C604– anions. The structure-directing influence of large cations on fulleride structures and the implications for Jahn–Teller distortions of the fulleride anions are discussed.

([2H8 ]BEDT–TTF)4Cl2 ·6D2O [BEDT–TTF=bis(ethylenedithio)tetrathiafulvalene] exhibits a transition from semimetal to semiconductor at T=160 K (Rosseinskyet al., J. Mater. Chem., 1993, 3, 801). This electronic transition is accompanied by a structural transition that is characterized by the reversible appearance of superstructure reflections corresponding to the doubling of the cell parameter b and a change in space group from Pcca to Pbcn. The crystal structures are very similar above and below T and the calculated intermolecular transfer integrals scarcely change. In contrast, from the difference in intramolecular bond lengths, it is clear that the two crystallographically independent BEDT–TTF molecules carry different charges at low temperature, suggesting that a degree of ionicity arising in the BEDT–TTF layer is responsible for the change in electrical behaviour.

The preparation of [N(CH3)4]C60· 1.5thf and characterisation of its electronic properties, using susceptibility, EPR and 13C MAS NMR measurements, is reported. X-Ray powder diffraction shows a simple hexagonal stacking sequence of close-packed C60 layers, with cations and solvent molecules located in the trigonal-prismatic sites. The electronic properties are consistent with narrow-band metallic behaviour at high temperature. A transition in susceptibility and EPR measurements is seen between 200 and 230 K. A similar synthesis affords a C602– compound with the same simple hexagonal fulleride packing.

([2H8]BEDT-TTF)4Cl2·6D2O [BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene] has been obtained as long black needles by electrocrystallisation of [2H8]BEDT-TTF in CH2Cl2 in the presence of [(C2H5)4N]Cl·D2O. It crystallises in the orthorhombic space group Pcca, a= 32.575(2)A, b= 6.709(1)A, c= 14.854(2)A, V= 3246(1)A3 and Z= 2. The structure consists of twisted (dihedral angle of 29°) pairs of crystallographically equivalent BEDT-TTF cations forming stacks parallel to c with close intermolecular S ⋯ S contacts along b, resulting in layers. A layered network of chlorine and water molecules linked by weak hydrogen bonds alternates with the layers of organic donor molecules. The conductivity parallel to b is 40 S cm–1 at 300 K, almost constant with decreasing temperature to ca. 160 K. Below 150 K the conductivity shows a temperature-dependent activation energy, ranging from 14 meV at 140 K to 6 meV at 10 K. It increases linearly by a factor of 3 by applying a pressure up to 24 kbar; the transition temperature decreases from 160 to 20 K. The anisotropy of the microwave conductivity is 0.5:240:3.6 S cm–1. The spin and static susceptibilities measured, respectively, by electron paramagnetic resonance (EPR) and Faraday magnetometry are temperature independent between 70 and 300 K, and obey a Curie–Weiss law below 50 K with θ=–4 K. The calculated band structure and Fermi surface show twodimensional character of both electron and hole pockets, with the possibility of 2kF nesting.

The structural, magnetic and conducting properties of the La2 –xSrxCuO4 –δ system (0≤x≤ 0.13, 0.01 ≤δ≤ 0.04) are examined as functions of temperature, and combined with assignment of the formal Cu oxidation state. High-resolution powder neutron structural results confirm that the correct space group is Abma, ruling out charge-density wave behaviour as well as other Fermi-surface instability mechanisms, as being responsible for the tetragonal-to-orthorhombic phase transition. The reduced magnitude and eventual disappearance of the orthorhombic distortion as the formal Cu oxidation state increases is well described by the better matching of the (La,Sr)—O and Cu—O bond distances in the two layers, (Ln2O2) and (CuO2), resulting in the tolerance factor increasing into the stability range of the K2NiF4 structure. The structural data reveal that there is a smooth variation of all structural parameters as the formal Cu oxidation state increases, except in the bond-length ratio (dax–deq)/(dax+deq), where dax and deq are the axial and equatorial Cu—O bond distances of the severely elongated CuO6 octahedra. This ratio peaks at the formal Cu oxidation state nearest to + 2 in our series (i.e.+ 2.01) to a value of 0.1207(3), decreasing at both higher and lower oxidation states. An electronic Jahn–Teller mechanism is found superior to a superexchange mechanism in explaining the orbital ordering, indicating that the holes formed on Sr2+ doping have σ* character. Analysis of the magnetic Bragg scattering resulting from antiferromagnetic ordering of the copper spins leads to the evaluation of the staggered Cu moment which is reduced on doping and disappears at a formal Cu oxidation state of between +2.01 and +2.04. The data support localised models for the Cu spin system and provide no evidence for spin-density wave behaviour. Analysis of resistivity data at low temperatures shows the occurrence of variable-range hopping even after the long-range magnetic order has disappeared, demonstrating that the electronic states at the Fermi level are localised. Doping by oxygen vacancies and/or Sr2+ cations leads to the introduction of impurity states into the Mott–Hubbard gap. Each carrier extends over two or three copper sites, with the localisation length ξ increasing to beyond the mean interdopant separation on approaching the metal–insulator transition. As the temperature increases, there is a crossover to a transport mechanism based on excitation to the mobility edge in the overlapping upper-Hubbard impurity and valence bands with the metal–insulator transition being of the Anderson type.

EPR and static and magic-angle spinning NMR measurements reveal a metal-insulator transition at 40 K in (NH3)K3C60: the electronic structure is discussed in comparison with superconducting K3C60.

A coordination polymer with 74% extra-framework volume is prepared by predictable linking of the honeycomb network to generate a framework-structured solid designed with two distinct connecting ligands.

Thin films of germanium-doped zinc oxide have been deposited by atomic layer deposition. The zinc oxide matrix was grown from cyclic pulses of diethylzinc and water vapour over the temperature range of 100–350 °C substrate temperature. Tetramethoxygermanium(IV) was employed as a novel germanium-doping source, which could be incorporated up to 17 at%. At 2.1 at% germanium doping at a deposition temperature of 250 °C, the maximum carrier concentration of 2.14 × 1020 cm−3 coincides with a carrier mobility of approximately 5 cm2 V−1 s−1. No evidence for the formation of nanometre-scale germanium clustering or segregation was observed in the X-ray diffraction patterns or high-resolution transmission electron micrographs of these films. The near band edge photoluminescence shifts to higher energy with increasing germanium incorporation either by the Burstein–Moss mechanism or by alloy formation.

The 12-layer hexagonal perovskite Ba4YMn3O11.5 (Rm, referred to as 12R) was transformed to a 6-layer mixed valent Mn3+/4+ hexagonal perovskite Ba4YMn3O10.7 (P63/mmc, referred to as 6H) via a partial-reduction in a N2 flow. This phase transformation between the 12R and 6H phases is redox-reversible. In contrast with the 12R-type Ba4YMn3O11.5 structure containing c-BaO2.75 and h-BaO3 layers with a (cchh)3 stacking, the 6H-type Ba4YMn3O10.7 structure consists of the cubic (c) BaO2.87 and hexagonal (h) BaO2.33 layers with a (cch)2 stacking, showing a preference of oxygen vacancy distribution in the hexagonal layers over the cubic layers. The h-BaO2.33 layer in the 6H-type Ba4YMn3O10.7 transforms two-thirds of face-sharing octahedral Mn2O9 dimers into edge-sharing pyramidal Mn2O8 units, sharing corners with Y octahedra/pyramids. Impedance measurements suggested that the 6H-type material is insulating with a bulk electrical resistivity of ∼107 Ω cm at 303 K, significantly higher than that for the 12R-type Ba4YMn3O11.5 by ∼4 orders of magnitude.

Atomic layer deposition is used to deposit crystalline anatase TiO2 on 500 nm silica support particles over a range of shell thicknesses. The core–shell morphology combines nanometer thickness titania with silica that is readily separable from liquid media. The composite particles are evaluated as photocatalysts for destruction of the model pollutant methyl orange and, after deposition of platinum co-catalyst, for the sacrificial generation of hydrogen from water. The catalytic activities normalized to surface area are higher than those of P25 mixed anatase/rutile titania nanoparticles.

Oleophilic magnetic nanoparticles can be encapsulated within stable surface functionalized oil-in-water emulsion droplets. Judicious control of the droplet surface functionality affords these disperse soft materials a unique transition between a free flowing and a gelled state. This transition is mediated by a simple pH switch. High level control over the gelation step is demonstrated as is a concomitant change in the magneto-response—from high magnetophoretic mobility to magneto-actuation. All processes show reversibility and modularity that allows the fabrication of complex, multi-component and site-isolated soft materials. These functional magnetic emulsions have potential bio-medical relevance as non-invasive, responsive in vivo delivery vehicles.

A series of high surface area nanocrystalline copper manganese oxide catalysts have been prepared by supercritical anti-solvent (SAS) precipitation using CO2 and tested for the ambient temperature oxidation of CO. The catalysts were prepared by precipitation from an ethanol/metal acetate solution and the addition of small quantities of water was found to result in a mixed acetate precursor with surface areas >200 m2 g−1, considerably higher than those prepared by conventional precipitation methods. The surface area of the final calcined mixed oxide was found to be dependent upon the initial water concentration. XRD and FT-IR analysis indicated that the addition of water promoted the formation of carbonate species in the amorphous acetate precursor, with high resolution TEM and STEM showing the material to consist of spherical agglomerations of fibrous strings of ca. 30 nm length. This is in contrast to the material prepared in the absence of water, using the same SAS methodology, which typically yields quasi-spherical particles of 100 nm size.

Linking of ‘all chair’ two-dimensional honeycomb networks, structurally analogous to CFx, with the 4-aminopyridine ligand leads to a three-dimensional molecular framework.

Linking of hydrogen bonded sheets by coordination polymer chains produces a three-dimensional solid derived from two distinct structural components.

A homochiral three-dimensional zinc aspartate has been synthesised via reflux and solvothermal methods, which due to the coordinative flexibility of zinc displays three distinct coordination geometries and three coordination modes of aspartic acid to zinc.

The non-metallic, magnetically-dilute, cation-disordered perovskite La1.5Sr0.5RhMnO6 is shown to be a soft ferromagnet with T(c) = 105 K with an ordered magnetic moment of 3.56(8) μ(B) per Mn.

The rigidity of the coordination polymer framework of Ni2(4,4′-bipy)3(NO3)4 is demonstrated quantitatively by determination of the structures of both ethanol-loaded and desolvated forms, showing only a small relaxation of the structure on guest loss.

The organo-pillared octahedral–tetrahedral (O/T) layer solid Co4(SO4)(OH)6(H2NC2H4NH2)0.5·3H2O is robust to loss of water molecules within the galleries, thermally stable to 300 °C and orders as a metamagnet below 14 K.

The inverse spinel CoFe2O4 is prepared as nanoparticles with a range of controlled sizes. Synthesis is performed using solvothermal and coprecipitation chemistry, and a two capping group coprecipitation procedure using oxalic acid and ethylenediamine or triethanolamine is shown to afford sub-10 nm, controlled size nanoparticles. A pronounced particle size–activity relationship is observed for CO oxidation catalysis for the studied range of particle sizes. In addition, these unsupported nanoparticle catalysts readily undergo activation during catalysis and exhibit both structural and performance stability under the test reaction conditions.

Protonation of chiral porous materials introduces a Brønsted acid centre, the structure of which is unique to the heterogeneous phase requiring pore wall confinement for stable isolation.

The first examples of anionic-neutral mixed ligand frameworks prepared from 1,3,5-benzenetrisbenzoate (BTB) and 4,4′-bipyridyl (bipy) are reported. Framework 1, of composition [Ni(HBTB)(bipy)]·(guests), is a triply interpenetrated (3,5)-connected grabinodal network that has a 1-D channel structure exhibiting permanent porosity. Framework 2, which was prepared under identical conditions but in the presence of toluene, has the formula [Ni3(BTB)2(EG)3(bipy)3]·(toluene) (where EG = ethylene glycol). 2 is a dense phase of triply interpenetrated rare (3,4)-connected tfzbinodal networks that contains intercalated toluene in isolated voids. The primary influence for the formation of 2 are numerous hydrophobic interactions between the internal framework surface and the included toluene guest molecule.

Post-synthetic derivatisation of a porous material produces a functionalized material that binds the metal complex V(O)acac2, in contrast to the unfunctionalized precursor, which is inactive for complex binding.

Two L-proline based homochiral frameworks synthesised via diffusion and solvothermal methods display distinct L-proline bonding modes, one N,O chelating and one O,O bridging with amine nitrogen not bound to the metal, with binding mode dependent upon the degree of protonation of the amino acid.

The chiral and porous cubic coordination polymer Ni3- (btc)2(py)6(eg)6·xeg·yH2O (btc = 1,3,5-benzenetricarboxylate, py = pyridine, eg = ethylene glycol, x ≈ 3, y ≈ 4) is based on the interpenetration of four independent (10,3)-a networks, and contains large interconnected cavities with diameter 16 A which may be desolvated without irreversibly destroying the porous framework structure.

Three new n = 5 members of the B-cation deficient hexagonal perovskite AnBn−1O3n family, La5Zn0.5Ti3.5O15, La5GaTi3O15 and La5AlTi3O15, have been synthesised and their crystal structures determined. Their microwave dielectric properties and AC conductivities, as well as those of a known material, La5Mg0.5Ti3.5O15, were characterized. These four analogues adopt a 10H structure with an AO3 stacking sequence of (hhccc)2 with empty octahedral sites between two hexagonal layers. Zn, Mg, Ga and Al atoms prefer the octahedral sites between two cubic layers to those between cubic and hexagonal layers. The Mg phase exhibits more extensive B-cation order than the Zn, Ga and Al phases. These three new materials exhibit relatively high dielectric permittivity e, 28–37, modest Q × f values, 23 000–30 000 GHz and a negative temperature coefficient of resonant frequency τf from −37 ppm/°C to −55 ppm/°C. τf of these four members and other n = 5 La-based and Ba-based members of B-cation hexagonal deficient perovskites are compared and the correlations between their τf and tolerance factors are discussed. Based on the comparison of these four materials with BaLa4Ti4O15, correlations between the defects, conductivity and microwave dielectric loss are also addressed.

A microporous hypercrosslinked polymer resin was synthesized and shown to adsorb 3.04 wt.% hydrogen at 77 K and 15 bar; this represents the highest level of hydrogen adsorption yet observed for an organic polymer.

We report magnetisation, conductivity and structural data on the Ruddlesden-Popper MnIII/MnIV oxides LnSr2Mn2O7 (Ln = La, Tb); while LaSr2Mn2O7 undergoes an insulator-metal transition and an increase in spontaneous magnetisation at 132 K, the isostructural terbium compound is semiconducting and paramagnetic throughout the range 4.2 < T/K < 300.

The synthesis and characterisation of alkali metal fullerides with complex counterions consisting of ammonia ligands coordinated to lithium cations is discussed. The body-centred cubic packing and accompanying low density of fulleride anions produces localisation of the t1u outer electrons of the fulleride anions. This is demonstrated by the electronic behaviour of the x = 3 and 5 members of the series, the latter representing the first detailed study of the electronic behaviour of a localised electron fulleride with five electrons per anion.

The new ternary fulleride Ba2CsC60 is prepared by reduction of C60 by the metals in liquid ammonia followed by crystallisation at high temperature and adopts a novel orientational (dis)ordering of the anions in space group Fm.

Reaction of face-centred cubic Na3C60 with ammonia at room temperature affords body-centred cubic (NH3)6Na3C60 in which both octahedral and tetrahedral interstices in the fulleride array are occupied: despite the similarity in C603–packing to Cs3C60, no superconductivity is observed above 6 K.

The synthesis, crystal chemistry and electronic properties of metal fullerides are described. The behaviour of solid C60 as an intercalation host is rationalised in terms of the electronic structure of the molecule. The use of chemical synthesis to control the electronic properties of the fullerides is emphasised.

Incorporation of elemental phosphorus into hexagonal-packed C60 gives the new phase {(P4)2C60}; characterisation by powder diffraction and multinuclear solid-state NMR studies show the P4 tetrahedra occupy trigonal prismatic sites and confirm the retention of the molecular nature of the P4 guest.

Superconducting alkali metal fullerides can be synthesized in less than 60 s reaction time using a microwave-induced argon plasma; the rapid synthesis of K3C60 is described.