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Responsive metal-organic frameworks (MOFs) that display sigmoidal isotherms triggered by discrete gas pressure-induced structural transformations are highly promising materials for energy related applications. However, their lack of transportability via continuous flow hinders their application in systems and designs that rely on liquid agents. We herein present examples of responsive liquid systems which exhibit a breathing behaviour and show step-shaped gas sorption isotherms, akin to the distinct oxygen saturation curve of haemoglobin in blood. Dispersions of flexible MOF nanocrystals in a size-excluded silicone oil form stable porous liquids exhibiting gated uptake for CO2, propane and propylene, as characterized by sigmoidal gas sorption isotherms with distinct transition steps. In situ X-ray diffraction studies show that the sigmoidal gas sorption curve is caused by a narrow pore to large pore phase transformation to the flexible MOF nanocrystals, which respond to gas pressure despite being dispersed in silicone oil. Given the established flexible nature and tunability of a range of MOFs, these results herald the advent of breathing porous liquids whose sorption properties can be tuned rationally for a variety of technological applications.

We report on the implementation of the concept of a photochemically elicited two‐carbon homologation of a π‐donor–π‐acceptor substituted chromophore by triple‐bond insertion. Implementing a phenyl connector between the slide‐in module and the chromophore enabled the synthesis of cylohepta[b]indole‐type building blocks by a metal‐free annulative one‐pot two‐carbon ring expansion of the five‐membered chromophore. Post‐irradiative structural elaboration provided founding members of the indolo[2,3‐d]tropone family of compounds. Control experiments in combination with computational chemistry on this multibond reorganization process founded the basis for a mechanistic hypothesis., By enabling cooperativity of substituent and solvent effects, the concept of a photochemically triggered two‐carbon ring expansion was implemented to open a modular synthetic access to cyclohepta[b]indole‐type buildings blocks (see scheme).

A metal–organic framework (MOF) heterostructured thin film of 3D Cu3btc2 on 2D SURMOF-2 was developed for VOC adsorption. This heterostructured thin film shows higher VOC storage capacity than the two components and a counter-intuitive uptrend of adsorption ability (dimensionless normalized storage capacity) with increasing the size of VOCs.

Angewandte Chemie / International edition 61(21), e202117565 (2022). doi:10.1002/anie.202117565, The high-pressure behaviour of flexible zeolitic imidazolate frameworks (ZIFs) of the ZIF-62 family with the chemical composition M(im)2-x(bim)x is presented (M2+ = Zn2+, Co2+; im– = imidazolate; bim– = benzimidazolate, 0.02 ≤ x ≤ 0.37). High-pressure powder X-ray diffraction shows that the materials contract reversibly from an open pore (op) to a closed pore (cp) phase under a hydrostatic pressure of up to 4000 bar. Sequentially increasing the bim– fraction (x) reinforces the framework, leading to an increased threshold pressure for the op-to-cp phase transition, while the total volume contraction across the transition decreases. Most importantly, the typical discontinuous op-to-cp transition (first order) changes to an unusual continuous transition (second order) for x ≥ 0.35. This allows finetuning the void volume and the pore size of the material continuously by adjusting the pressure, thus opening new possibilities for MOFs in pressure-switchable devices, membranes, and actuators., Published by Wiley-VCH, Weinheim

Metal-organic framework (MOF) glasses are a new class of microporous glass materials with immense potential for applications ranging from gas separation to optics and solid electrolytes. Due to the inherent difficulty to determine the atomistic structure of amorphous glasses, the intrinsic structural porosity of MOF glasses is only poorly understood. In this work, the porosity features of a series of prototypical MOF glass formers from the family of zeolitic imidazolate frameworks (ZIFs) and their corresponding glasses is investigated comprehensively. CO2 gas sorption at 195 K allows to follow the evolution of microporosity when transforming from the crystalline to the glassy state of these materials. Based on these data, the pore volume and the real density of the ZIF glasses is quantified for the first time. Additional hydrocarbon sorption data (n-butane, propane and propylene) together with X-ray total scattering experiments prove that the porosity features (in particular the pore size and the pore limiting diameter) of the ZIF glasses depend on the types of organic linkers present in the glass network. This allows formulating first design principles for a targeted tuning of the intrinsic microporosity of MOF glasses. Importantly, these principles are counterintuitive and contrary to established porosity design concepts for crystalline MOFs but show similarities to strategies previously developed for porous polymers.

Flexible metal-organic frameworks (MOFs) exhibit large potential as next-generation materials in areas such as gas sensing, gas separation and mechanical damping. By using a mixed metal approach, we report how the stimuli reponsive phase transition of flexible pillared-layered MOFs can be tuned over a wide range. Different Cu2+ to Zn2+ metal ratios are incorporated into the materials by using a simple solvothermal approach. The properties of the obtained materials are probed by differential scanning calorimetry and CO2 sorption measurements, revealing stimuli responsive behaviour as a function of metal ratio. Pair distribution functions derived from X-ray total scattering experiments suggest a distortion of the M2 paddlewheel as a function of the Cu content. We rationalize these phenomena by the different distortion energies of Cu2+ and Zn2+ ions to deviate from the square pyramidal structure of the relaxed paddlewheel node. Our work follows on from the large interest in tuning and understanding the materials properties of flexible MOFs, highlighting the large number of parameters that can be used for the targeted manipulation and design of properties of these fascinating materials.

The guest-dependent flexibility of the pillared-layered metal–organic framework (MOF), Zn2bdc2dabco·X(guest), where guest = EtOH, DMF or benzene, has been examined by high-pressure single crystal X-ray diffraction. A pressure-induced structural phase transition is found for the EtOH- and DMF-included frameworks during compression in a hydrostatic medium of the guest species, which is dependent upon the nature and quantity of the guest in the channels. The EtOH-included material undergoes a phase transition from P4/mmm to C2/m at 0.69 GPa, which is accompanied by a change in the pore shape from square to rhombus via super-filling of the pores. The DMF-included material undergoes a guest-mediated phase transition from I4/mcm to P4/mmm at 0.33 GPa via disordering of the DMF guest. In contrast, the benzene-included framework features a structure with rhombus-shaped channels at ambient pressure and shows direct compression under hydrostatic pressure. These results demonstrate the large influence of guest molecules on the high-pressure phase behavior of flexible MOFs. Guest-mediated framework flexibility is useful for engineering MOFs with bespoke pore shapes and compressibility., The guest-dependent flexibility of the pillared-layered metal–organic framework (MOF), Zn2bdc2dabco·X(guest), where guest = EtOH, DMF or benzene, has been examined by high-pressure single crystal X-ray diffraction.

Metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) have been thoroughly investigated with regards to applications in gas separation membranes in the past years. More recently, new preparation methods for MOFs and COFs as particles and thin‐film membranes, as well as for mixed‐matrix membranes (MMMs) have been developed. We will highlight novel processes and highly functional materials: Zeolitic imidazolate frameworks (ZIFs) can be transformed into glasses and we will give an insight into their use for membranes. In addition, liquids with permanent porosity offer solution processability for the manufacture of extremely potent MMMs. Also, MOF materials influenced by external stimuli give new directions for the enhancement of performance by in situ techniques. Presently, COFs with their large pores are useful in quantum sieving applications, and by exploiting the stacking behavior also molecular sieving COF membranes are possible. Similarly, porous polymers can be constructed using MOF templates, which then find use in gas separation membranes., Metal–organic frameworks, covalent organic frameworks, polymers, and composites are disruptive key technologies for gas separation membranes. This Minireview highlights the state of the art in materials and material development and their utilization in membrane applications in highly relevant processes such as carbon capture, energy‐ and resource‐efficient separations of basic chemicals, and quantum sieving.

The pillared-layered metal–organic framework compounds M2(BME-bdc)2(dabco) (M2+ = Zn2+, Co2+, Ni2+, Cu2+; BME-bdc2– = 2,5-bis(2-methoxyethoxy)-1,4-benzenedicarboxylate; dabco = diazabicyclo[2.2.2]octane) exhibit structural flexibility and undergo guest and temperature-induced reversible phase transitions between a narrow pore (np) and a large pore (lp) form. These transitions were analyzed in detail by powder X-ray diffraction ex and in situ, isothermal gas adsorption measurements and differential scanning calorimetry. The threshold parameters (gas pressure or temperature), the magnitude of the phase transitions (volume change) as well as their transition enthalpies are strikingly dependent on the chosen metal cation M2+. This observation is assigned to the different electronic structures and ligand field effects on the coordination bonds. Accordingly, in situ powder X-ray diffraction measurements as a function of CO2 pressure reveal different mechanisms for the np to lp phase transition during CO2 adsorp...

Multiphotonenabsorption (MPA) ist eine der wichtigsten nichtlinear-optischen (NLO) Effekte und hat verschiedene Anwendungen, z. B. in Telekommunikation, Verteidigung, Photonik und Biomedizin. Bekannte MPA-Materialien sind Farbstoffe, Quantenpunkte, metallorganische Verbindungen und konjugierte Polymere, die oft als Dispersion in Losung verwendet werden. Wir zeigen wie Metall-organische Gerusteverbindungen (MOFs), eine neuartige NLO-Festkorpermaterialklasse, so entworfen werden konnen, dass sie ausergewohnlich starkes MPA-Verhalten zeigen. MOFs, die aus Zirconium- und Hafnium-Oxo-Clustern bestehen und einen Tetraphenylethen(TPE)-basierten Chromophor-Linker beinhalten, zeigen rekordverdachtig hohe Zweiphotonenabsoptionsquerschnitte mit bis zu 3600 GM. Das einzigartige, modulare Baukastenprinzip von MOFs erlaubt eine Optimierung und Verbesserung ihrer MPA-Eigenschaften, gestutzt auf einen theoriebasierten Ansatz, durch die Berucksichtigung von masgeschneiderter Ladungspolymerisation, konformativer Spannung, dreidimensionaler Anordnung und Ausrichtung der Chromophore im Kristall.

Defect engineering is a strategy for tailoring the properties of metal-organic frameworks (MOFs). Plenty of efforts have been devoted to study the defect chemistry and structures of bulk MOFs; however, the reported example of a defect-engineered surface-mounted MOF (SURMOF) thin film is rare. In this work, defects were incorporated in SURMOF thin films by using defect-generating linkers and taking advantage of the liquid-phase stepwise epitaxial layer-by-layer growth (LBL). Two methods based on the LBL, named mixing method and alternating method, are proposed for incorporating defects in the prototypical SURMOF HKUST-1 by partially substituting the parent H3btc (benzene-1,3,5-tricarboxylic acid) linker with a set of defect-generating linkers H2ip (isophthalic acid), H2OH-ip (5-hydroxyisophthalic acid), and H2pydc (3,5-pyridinedicarboxylic acid). The crystallinity and phase purity of the obtained "defected" SURMOFs were confirmed by X-ray diffraction, infrared reflection absorption spectroscopy, and Raman spectroscopy. The incorporation of the defect-generating linkers and the types of induced defects were characterized by ultraviolet-visible spectroscopy, time-of-flight secondary ion mass spectrometry, methanol adsorption, scanning electron microscopy, and 1H nuclear magnetic resonance spectroscopy (after digestion of the samples). These two methods provide avenues for controlling the defect formation in MOF thin films.

The title compound [Pt(NH3)4]Cl2 (1), prepared by reaction of (NH4)2[PtCl4] with an excess of NH3 in aqueous solution, was crystallized from water and its structure redetermined by single-crystal X-ray diffraction at four different temperatures in the range from 273 K down to 100 K. 1 is composed of square-planar [Pt(NH3)4]2+ complex cations and Cl− anions and crystallizes in the tetragonal crystal system. Remarkably, the solid state structure is porous (approx. 18% of the crystal volume is void space) and features one-dimensional open channels of a diameter of ∼3–4 A. Unexpectedly, these channels are free of solvent molecules, although the crystals were obtained from aqueous solutions. N H⋯Cl hydrogen bonding interactions between the square-planar [Pt(NH3)4]2+ dications and the Cl− counter ions result in a three-dimensional hydrogen bonding network that stabilizes the porous solid state structure. The hydrogen atoms of the ammonia ligands and their corresponding N H⋯Cl hydrogen bonds are localized at low temperature (space group I4/mmm) but disorder dynamically above 173 K (space group P4/mmm). The order-disorder transition is accompanied by significant changes in the Pt–Pt stacking distances and a fourfold reduction of the unit cell volume.

Porous glasses from metal-organic frameworks (MOFs) represent a new class of functional inorganic-organic materials, which have been proposed for applications ranging from solid electrolytes to radioactive waste storage. So far, just a few zeolitic imidazolate frameworks (ZIFs), a subset of MOFs, have been reported to melt and the structural and compositional requirements for MOF melting and glass formation are poorly understood. Here, we show how the melting point of the prototypical ZIF-4/ZIF-62(M) frameworks (composition M(im)2-x(bim)x; M2+ = Co2+, Zn2+; im- = imidazolate; bim- = benzimidazolate) can be controlled systematically by adjusting the molar ratio of the two imidazolate-type linkers im- and bim-. By covering the entire range from x = 0 to 0.35, we unveil a delicate transition from ZIF materials showing sequential amorphization/recrystallization to derivatives exhibiting coherent melting and a liquid phase that is stable over a large temperature window. The melting point of this ZIF system is a direct function of x and can be lowered from ca. 430 °C to only 370 °C, by far the lowest melting point reported for a three-dimensional porous MOF. On the basis of our results, we postulate compositional requirements for ZIF melting and glass formation, which may guide the search for other meltable ZIFs. Moreover, gas physisorption experiments establish that the ZIF glasses adsorb technologically relevant C3 and C4 hydrocarbons. Importantly, the adsorption kinetics are much faster for propylene compared to propane and are also dependent on the im-:bim- ratio, thus demonstrating the potential of these ZIF glasses for applications in gas separation.

We report the first microporous cobalt imidazolate glass obtained from a meltable cobalt-based zeolitic imidazolate framework, ZIF-62(Co). Crystalline ZIF-62(Co) is constructed from Co2+ cations and two different imidazolate-type linkers, namely conventional imidazolate and benzimidazolate. The microporous framework melts at ∼430 °C and converts into a glass upon cooling to room temperature. X-Ray total scattering and Raman spectroscopy reveal that the local structure of the glass and the crystalline parent material are very similar. Magnetic measurements and X-ray diffraction uncover that ZIF-62(Co) partially decomposes upon melting and glass formation resulting in the reduction of ∼3% of the Co2+ ions to metallic cobalt. Most importantly, the ZIF glass retains almost 50% of the porosity of crystalline ZIF-62(Co). Our results pave the way for the realisation of metal–organic framework glasses containing open shell metal ions, as well as the application of these porous glasses in gas separation, energy storage and catalysis.

The understanding of lithium–oxygen coordination systems is important for making better lithium conductors as well as active materials for lithium ion batteries. Here, we report a systematic investigation on coordination environments in lithium coordination polymers (LCPs) through the syntheses and analyses of six new crystals composed of lithium ions and anthraquinone (aq) derivative anions, where the negative charges are distributed in π-conjugation systems. Their structures were determined by single-crystal X-ray diffraction to be (1) [Li2(23dcaq)(H2O)] in space group P21/c, (2) [Li(23dcaqH)] in P21/c, (3) [Li2(15dhaq)(H2O)2] in P21/c, (4) [Li2(14dhaq)(H2O)2] in Pnma, (5) [Li(14dhaqH)(H2O)] in P212121 and (6) [Li(14hnaq)(H2O)] in P212121 (23dcaq2− = 2,3-dicarboxy-aq, 14dhaq2− = 1,4-dihydroxy-aq, 15dhaq2− = 1,5-dihydroxy-aq and 14hnaq− = 1-hydroxy-4-nitro-aq). Through the comprehensive structure analysis of these materials as well as other LCPs, we found that when considering the longest C–O bond in the π-conjugation system of an anionic organic molecule and its coordination to a Li ion, there is a weak inverse relationship between the C–O and Li–O bond lengths. In addition, despite exhibiting optical band edges below 2 eV and 1D π-stacking connectivity, conductivity measurements on single crystals of 1–6 confirmed that they are all electronic insulators. We rationalize this finding on the basis of π-orbital delocalization, which is more restricted in the aq-based LCPs compared to known semiconducting hybrid materials.

We report how mechanical and dynamical properties in formate-based perovskites can be manipulated by the preparation of an A-site solid-solution. In the series [NH3NH2]1−x[NH3OH]xZn(HCOO)3 with xmax = 0.48, the substitution of [NH3NH2]+ by [NH3OH]+ is accompanied by a series of complex changes in crystal chemistry which are analysed using PXRD, SCXRD, 1H solid state NMR, DSC and nanoindentation. NMR shows increased motion of [NH3NH2]+ in [NH3NH2]0.52[NH3OH]0.48Zn(HCOO)3, which results in a shift of the ferroelectric-to-paraelectric phase transition temperature from Tc = 352 K (x = 0) to Tc = 324 K (x = 0.48). Additionally, the loss of hydrogen bonds directly influences the mechanical response of the framework; the elastic moduli and hardnesses decrease by around 25% from E110 = 24.6 GPa and H110 = 1.25 GPa for x = 0, to E110 = 19.0 GPa and H110 = 0.97 GPa for x = 0.48. Our results give an in-depth insight into the crystal chemistry of ABX3 formate perovskites and highlight the important role of hydrogen bonding and dynamics.

We report the synthesis of a 2D-layered metal-organic framework incorporating weakly interacting chains designed to aid exfoliation of the layers into nanosheets. Dispersion of the nanosheets exposes labile metal-sites which are shown to exchange solvent molecules allowing the nanosheets to act as sensors in suspension.

Three highly crystalline Cu(II)-polyoxometalate (POM) complexes, [Cu1.5(H2O)7.5PW12O40]·4.75H2O and cis- and trans-[Cu2(H2O)10SiW12O40]·6H2O, were successfully synthesized and characterized by single crystal and powder X-ray diffraction as well as thermogravimetric analysis. All complexes feature octahedrally coordinated, Jahn–Teller-distorted CuII centres, which are coordinated by one terminal oxygen atom of the POM anion and five water molecules. The crystal structure of [Cu1.5(H2O)7.5PW12O40]·4.75H2O, reveals four-fold disorder at one of the two Cu-sites, whereas [Cu2(H2O)10SiW12O40]·6H2O crystallizes in two fully-ordered polymorphic forms: a monoclinic structure containing an angled cis configuration of the Cu-POM-Cu molecule and a triclinic structure containing a linear trans configuration. Density functional theory (DFT) calculations show that the cis polymorph of [Cu2(H2O)10SiW12O40]·6H2O is more stable than the trans form by about 30 kJ mol−1.

Eleven novel coordination compounds, composed of chrysazin (1,8-dihydroxyanthraquinone) and different first-row transition metals (Fe, Co, Ni, Cu), were synthesised and the structures determined by single-crystal X-ray diffraction. The synthetic trends were investigated using high-throughput synthesis under systematic variation of concentration and reagent stoichiometry: for complexes containing Co, Ni or Cu crystallisation was improved by low ligand : metal ratios, while the effect of concentration depended on the metal used. The compounds crystallise as discrete clusters, apart from two, which contain long Cu–O bonds which may allow the two compounds to be considered one-dimensional coordination polymers. One of these compounds shows a distance between aryl rings of less than 3.26 A, which is shorter than that in graphite, suggesting applications as an organic–inorganic semiconductor. The compound was found to be insulating by single-crystal and powder AC-impedance measurements, and this result is discussed with reference to the electronic structure calculated using density-functional theory.

There is an increasingly large amount of interest in metal-organic frameworks (MOFs) for a variety of applications, from gas sensing and separations to electronics and catalysis. Their exciting properties arise from their modular architectures, which self-assemble from different combinations of metal-based and organic building units. However, the exact mechanisms by which they crystallize remain poorly understood, thus limiting any realisation of real “structure by design”. We report important new insight into MOF formation, gained using in situ X-ray diffraction, pH and turbidity measurements to uncover for the first time the evolution of metastable intermediate species in the canonical zeolitic imidazolate framework system, ZIF-8. We reveal that the intermediate species exist in a dynamic pre-equilibrium prior to network assembly and, depending on the reactant concentrations and the progress of reaction, the pre-equilibrium can be made to favour under- or over-coordinated species, thus accelerating or inhibiting crystallization, respectively. We thereby find that concentration can be effectively used as a synthetic handle to control particle size, with great implications for industrial scale-up and gas sorption applications. These finding enables us to rationalise the apparent contradictions between previous studies and, importantly, opens up new opportunities for the control of crystallization of network solids more generally, from the design of local structure to assembly of particles with precise dimensions.

Chemical science 9(6), 1654 - 1660 (2018). doi:10.1039/C7SC04952H, Published by RSC, Cambridge

Porosity switching in the crystalline solid state is a unique phenomenon observed only in a limited number of materials. The switching behavior of two metal-organic frameworks as well as their respective solid solutions of composition [Zn 2 (BME-bdc) x (DB-bdc) 2−x dabco] n (x = 2; 1.5; 1.0; 0.5; 0) is studied in situ during the adsorption of CO 2 and Xe using X-ray diffraction and NMR techniques. The diffraction data, measured during the adsorption suggest a direct one-step phase transition (switching) from the narrow pore phase to the large pore phase beyond the transition pressure. An intermediate phase was found only in one compound within a narrow pressure range around the phase transition pressure region. In situ high-pressure 13 C NMR spectroscopy of adsorbed CO 2 also allowed following the gating behavior of the studied materials by monitoring the signal of adsorbed CO 2 . The 13 C NMR spectra exhibit a pronounced broadening indicating a certain degree of order for the adsorbed molecules inside the pores. This ordering effect and the resulting line broadening depend on the linker functionalization as could be confirmed by corresponding molecular dynamics (MD) simulations.

A series of four Zn2+ metal–organic frameworks containing functionalised isophthalate linkers and 4,4′-bipyridine pillars have been prepared and characterised. Isophthalates which contain –OC3H2n+1 alkoxy side chains (with n = 1, 2 or 3) form frameworks with a 3D pillared-layer topology instead of the typical 2D layer topology of the renowned coordination polymers with an interdigitated structure (CIDs), which is found for shorter –OC2H5 side chains. The gas adsorption properties of the materials were analysed using N2, CO2 and O2 adsorption measurements at low temperatures.

Blue-color stimulated emission with low threshold power is observed from In- and Zn-MOFs, which feature a highly fluorescent chromophore densely packed and rigidly linked to the metal-ion centers in the solid state. The density-of-states and transition dipole moments are calculated and the stimulated emission phenomenon is correlated with these properties. MOE (Min. of Education, S’pore) Accepted version

Multi‐photon absorption (MPA) is among the most prominent nonlinear optical (NLO) effects and has applications, for example in telecommunications, defense, photonics, and bio‐medicines. Established MPA materials include dyes, quantum dots, organometallics and conjugated polymers, most often dispersed in solution. We demonstrate how metal–organic frameworks (MOFs), a novel NLO solid‐state materials class, can be designed for exceptionally strong MPA behavior. MOFs consisting of zirconium‐ and hafnium‐oxo‐clusters and featuring a chromophore linker based on the tetraphenylethene (TPE) molecule exhibit record high two‐photon absorption (2PA) cross‐section values, up to 3600 GM. The unique modular building‐block principle of MOFs allows enhancing and optimizing their MPA properties in a theory‐guided approach by combining tailored charge polarization, conformational strain, three‐dimensional arrangement, and alignment of the chromophore linkers in the crystal. MOE (Min. of Education, S’pore) Accepted version

Functionalized metal–organic frameworks (fu-MOFs) of general formula [Zn2(fu-L)2dabco]n show unprecedentedly large uniaxial positive and negative thermal expansion (fu-L = alkoxy functionalized 1,4-benzenedicarboxylate, dabco = 1,4-diazabicyclo[2.2.2]octane). The magnitude of the volumetric thermal expansion is more comparable to property of liquid water rather than any crystalline solid-state material. The alkoxy side chains of fu-L are connected to the framework skeleton but nevertheless exhibit large conformational flexibility. Thermally induced motion of these side chains induces extremely large anisotropic framework expansion and eventually triggers reversible solid state phase transitions to drastically expanded structures. The thermo-responsive properties of these hybrid solid–liquid materials are precisely controlled by the choice and combination of fu-Ls and depend on functional moieties and chain lengths. In principle, this combinatorial approach allows for a targeted design of extreme thermo-mechanical properties of MOFs addressing the regime between crystalline solid matter and the liquid state.

Molecular engineering of seven closely related zinc ketoiminates, namely, [Zn(dapki)2], [Zn(daeki)2], [Zn(epki)2], [Zn(eeki)2], [Zn(mpki)2], [Zn(meki)2], and [Zn(npki)2], leads to the optimisation of precursor thermal properties in terms of volatilisation rate, onset of volatilisation, reactivity and thermal stability. The influence of functional groups at the imine side chain of the ligands on the precursor properties is studied with regard to their viability as precursors for atomic layer deposition (ALD) of ZnO. The synthesis of [Zn(eeki)2], [Zn(epki)2] and [Zn(dapki)2] and the crystal structures of [Zn(mpki)2], [Zn(eeki)2], [Zn(dapki)2] and [Zn(npki)2] are presented. From the investigation of the physico-chemical characteristics, it was inferred that all compounds are monomeric, volatile and exhibit high thermal stability, all of which make them promising ALD precursors. Compound [Zn(eeki)2] is in terms of thermal properties the most promising Zn-ketoiminate. It is reactive towards water, possesses a melting point of 39 °C, is stable up to 24 days at 220 °C and has an extended volatilisation rate compared to the literature known Zn-ketoiminates. It demonstrated self-saturated, water assisted growth of zinc oxide (ZnO) with growth rates in the order of 1.3 A per cycle. Moreover, it displayed a broad temperature window from TDep = 175–300 °C and is the first report of a stable high temperature (>200 °C) ALD process for ZnO returning highly promising growth rates.

Versatility in metal substitution is one of the key aspects of metal-organic framework (MOF) chemistry, allowing properties to be tuned in a rational way. As a result, it important to understand why MOF syntheses involving different metals arrive at or fail to produce the same topological outcome. Frequently, conditions are tuned by trial-and-error to make MOFs with different metal species. We ask: is it possible to adjust synthetic conditions in a systematic way in order to design routes to desired phases? We have used in situ X-ray powder diffraction to study the solvothermal formation of isostructural M2 (bdc)2 dabco (M=Zn, Co, Ni) pillared-paddlewheel MOFs in real time. The metal ion strongly influences both kinetics and intermediates observed, leading in some cases to multiphase reaction profiles of unprecedented complexity. The standard models used for MOF crystallization break down in these cases; we show that a simple kinetic model describes the data and provides important chemical insights on phase selection.

Poly(3,4-ethylenedioxythiophene) (PEDOT) is formed inside a metal–organic framework (MOF). MOF removal leads to sub-millimetre structures of the nanostructured conducting polymer., Reactions inside the pores of metal–organic frameworks (MOFs) offer potential for controlling polymer structures with regularity to sub-nanometre scales. We report a wet-chemistry route to poly-3,4-ethylenedioxythiophene (PEDOT)–MOF composites. After a two-step removal of the MOF template we obtain unique and stable macroscale structures of this conductive polymer with some nanoscale regularity.