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The Development of Hybrid Liquids and Glasses Louis Michael David Longley Metal-organic framework (MOF) glasses are amorphous materials formed by heating a crystalline MOF into the liquid phase and then cooling to form an amorphous solid material. The hybrid nature, defined here as materials containing both inorganic and organic bonding, of MOF glasses makes them distinct from previous glass families which have inorganic, organic, or metallic bonding. Most of the work on MOF glasses reported in the literature has focused on a sub-set of MOFs known as Zeolitic Imidazolate Frameworks (ZIFs). This work begins with a discussion of the structure of MOF glasses, particularly focusing on structure occurring beyond the first metal-metal correlation, also termed mid-range order. The observed midrange order in MOF glasses, measured by X-ray total-scattering, is interpreted using existing theory for inorganic glasses. The number of MOFs which form liquids on heating is small relative to the total number of known crystalline MOF structures due to decomposition of the framework occurring before melting in most cases. This work therefore takes an alternative approach to expanding the MOF glass domain through exploitation of the reactivity of the liquid phase as a route to the synthesis of new glass structures. ���Complex��� glasses formed from two parent MOF crystals heated into the liquid phase were synthesised, and their structures investigated by a variety of techniques, including x-ray total-scattering, differential scanning calorimetry, and electron microscopy. Following this work the scope of MOF glasses was further expanded through the production of composite materials of MOF and inorganic phosphate glasses. The structures and properties of these materials were also investigated thoroughly with attention being given to the interaction occurring at the interface between the two highly dissimilar components. Finally, as an extension of this, the interaction between a phosphate glass and a crystalline ZIF was investigated to probe the potential for inorganic glass crystalline MOF composite formation., Engineering and Physical Sciences Research Council

Metal-organic framework (MOF) glasses have become a subject of study due to their novelty as an entirely new category of melt quenched glass and their potential applications in areas such as ion transport and sensing. In this paper we show how MOF glasses can be combined with inorganic glasses in order to fabricate a new family of optically transparent materials composed of both MOF and inorganic glass domains. We present the design rules for this family of materials, use an array of experimental techniques to propose the bonding between inorganic and MOF domains, and show that the composites produced are more mechanically pliant than the inorganic glass itself.

Several distinct mixing processes and resulting microstructures have recently been reported in multicomponent glasses prepared from multiple metal-organic frameworks. Here, two illustrative examples of multicomponent zeolitic imidazolate framework (ZIF) glasses, the (aTZIF-4-Co)0.5(agZIF-62)0.5 blend and the ag[(ZIF-67)0.2(ZIF-62)0.8] flux melted glass, are studied. These materials are characterized by quantitative X-ray energy dispersive spectroscopy in the scanning transmission electron microscope. By advancing a partial ionization cross section methodology using standards of arbitrary morphology, quantitative nanoscale elemental analysis throughout the glass volume is achieved. In turn, phase diagrams describing the mixing states are presented, offering mechanistic insight into the formation of the observed microstructures. Significant miscibility was observed in ag[(ZIF-67)0.2(ZIF-62)0.8]. These findings establish phase-segregation and interdiffusion as two processes in multicomponent glass formation, which explains the different outcomes observed in blending and flux meltin

Microstructured metal-organic framework (MOF) glasses have been produced by combining two amorphous MOFs. However, the electronic structure of these materials has not been interrogated at the length scales of the chemical domains formed in these glasses. Here, we report a subwavelength spatially resolved physicochemical analysis of the electronic states at visible and UV energies in a blend of two zeolitic imidazolate frameworks (ZIFs), ZIF-4-Co and ZIF-62-Zn. By combining spectroscopy at visible and UV energies as well as at core ionization energies in electron energy loss spectroscopy in the scanning transmission electron microscope with density functional theory calculations, we show that domains less than 200 nm in size retain the electronic structure of the precursor crystalline ZIF phases. Prototypical signatures of coordination chemistry including d- d transitions in ZIF-4-Co are assigned and mapped with nanoscale precision.

Several distinct mixing processes and resulting microstructures have recently been reported in multicomponent glasses prepared from multiple metal-organic frameworks (MOFs). Here, two illustrative examples of multicomponent zeolitic imidazolate framework (ZIF) glasses, the (aTZIF-4-Co)0.5(agZIF-62)0.5 blend and the ag[(ZIF-67)0.2(ZIF-62)0.8] flux melted glass, are studied. These materials are characterized by quantitative X-ray energy dispersive spectroscopy in the scanning transmission electron microscope (STEM). By advancing a partial ionization cross-section methodology using standards of arbitrary morphology, quantitative nanoscale elemental analysis throughout the glass volume is achieved. In turn, phase diagrams describing the mixing states are presented, offering mechanistic insight into the formation of the observed microstructures. Significant miscibility was observed in ag[(ZIF-67)0.2(ZIF-62)0.8]. These findings establish phase-segregation and inter-diffusion as two processes in multi-component glass formation, which explains the different outcomes observed in blending and flux-melting., S.M.C. acknowledges the Henslow Research Fellowship and Girton College, Cambridge. K.E.M. acknowledges the Helmholtz Association for funding this research through a Postdoctoral Research Fellowship. T.D.B. would like to thank the Royal Society for a University Research Fellowship (UF150021), and EPSRC (grant EP/R015481/1). L.L. acknowledges an EPSRC studentship. P.A.M. acknowledges the EPSRC (EP/R008779/1). M.B. acknowledges the Leverhulme Trust Early Career Fellowship ECF-2016-611. C.-B.S. acknowledges support from the Leverhulme Trust project Breaking the non-convexity barrier, EPSRC grant EP/M00483X/1, EPSRC centre EP/N014588/1 and from CHiPS (Horizon 2020 RISE project grant). R.T. acknowledges funding from EPSRC grant EP/L016516/1 for the Cambridge Centre for Analysis. R.T. and C.-B.S. also acknowledge the Cantab Capital Institute for Mathematics of Information.

The majority of research into metal-organic frameworks (MOFs) focuses on their crystalline nature. Recent research has revealed solid-liquid transitions within the family, which we use here to create a class of functional, stable and porous composite materials. Described herein is the design, synthesis, and characterisation of MOF crystal-glass composites, formed by dispersing crystalline MOFs within a MOF-glass matrix. The coordinative bonding and chemical structure of a MIL-53 crystalline phase are preserved within the ZIF-62 glass matrix. Whilst separated phases, the interfacial interactions between the closely contacted microdomains improve the mechanical properties of the composite glass. More significantly, the high temperature open pore phase of MIL-53, which spontaneously transforms to a narrow pore upon cooling in the presence of water, is stabilised at room temperature in the crystal-glass composite. This leads to a significant improvement of CO2 adsorption capacity., The formation of composite materials has been widely exploited to alter the chemical and physical properties of their components. Here the authors form metal–organic framework (MOF) crystal–glass composites in which a MOF glass matrix stabilises the open pore structure of MIL-53, leading to enhanced CO2 adsorption.

The thermal behaviour of ZIF-8, Zn(meIm)2 in the presence of a sodium fluoroaluminophosphate glass melt was probed through differential scanning calorimetry and thermogravimetric analysis. The structural integrity of ZIF-8 was then determined by a combination of powder X-ray diffraction, Fourier transform infra-red and 1H nuclear magnetic resonance spectroscopy.

Metal-organic framework (MOF) glasses have become a subject of interest as a distinct category of melt quenched glass, and have potential applications in areas such as ion transport and sensing. In this paper we show how MOF glasses can be combined with inorganic glasses in order to fabricate a new family of materials composed of both MOF and inorganic glass domains. We use an array of experimental techniques to propose the bonding between inorganic and MOF domains, and show that the composites produced are more mechanically pliant than the inorganic glass itself., Metal-organic frameworks constitute a family of glass formers that is distinct from those that are polymeric, metallic, or inorganic. Here the authors show that they can be combined with different inorganic aluminophosphate glasses to produce a composite with mechanical properties intermediate between the two end-members.