Nanna Lærke Baun

The direct synthesis of amorphous metal-organic frameworks (aMOFs) is an appealing yet often avoided approach due to the perceived unpredictability of amorphous network formation. Here, we develop a strategy for aMOF synthesis using pre-formed nanoclusters and rigid organic linkers, providing enhanced control over disorder and defect chemistry while bypassing the traditional crystallise-amorphise approach. By systematically comparing this approach to other direct synthesis routes and using X-ray pair distribution function, thermogravimetric, and statistical analyses, we establish key design principles governing aMOF formation. We demonstrate that kinetic control-fast reactions under basic conditions at room temperature-suppresses crystallisation and drives amorphous network formation. The nanocluster approach consistently yields highly disordered frameworks with the shortest coherence lengths among direct synthesis methods. Additionally, we show that tuning metal composition through doping with kinetically inert cations restricts coordination reversibility, significantly increasing defect density and structural disorder. Structural analysis reveals that while aMOFs share motifs with crystalline polymorphs, they cannot be directly mapped onto known structures, highlighting the importance of more nuanced characterisation approaches. By developing a systematic approach to aMOF design, this work provides a foundation for tailoring structural disorder, expanding their potential for catalysis, adsorption, and transport applications.

We report the frustrated assembly of an amorphous metal–organic framework as a route to trap a metastable node within the network. Using x‐ray pair distribution function (PDF) analysis and density functional theory (DFT), we show that a distorted node forms instead of the more commonly observed and energetically favorable symmetric node. We rationalise this via a kinetically controlled sequence in which network percolation precedes node relaxation, in contrast to crystalline MOFs, where distorted nodes are permitted by favourable topological stabilisation. Our results show that frustrated assembly is an effective mechanism to install non‐equilibrium local motifs, establishing pathway control as a lever for node engineering in aMOFs.

We report the frustrated assembly of an amorphous metal–organic framework as a route to trap a metastable node within the network. Using x‐ray pair distribution function (PDF) analysis and density functional theory (DFT), we show that a distorted node forms instead of the more commonly observed and energetically favorable symmetric node. We rationalise this via a kinetically controlled sequence in which network percolation precedes node relaxation, in contrast to crystalline MOFs, where distorted nodes are permitted by favourable topological stabilisation. Our results show that frustrated assembly is an effective mechanism to install non‐equilibrium local motifs, establishing pathway control as a lever for node engineering in aMOFs.

Oxygen vacancies play a pivotal role in tailoring electronic, optical, and catalytic properties of reducible metal oxides. Here, we provide a complete overview of oxygen vacancy-induced structural evolution of iron-doped titanium oxide nanomaterials with insights into their synthesis, formation, and crystallization processes. Structural analysis combining multiple techniques reveals the formation of anatase nanoparticles at low Fe loadings (i.e., ≤ 10 at. % Fe). At intermediate Fe concentrations (i.e., 15-20 at. % Fe), a mixture of anatase and rutile forms with the presence of extended disordered defects similar to crystallographic shear planes. These become more notable at high Fe loadings (i.e., ≥ 30 at. % Fe) with the complete transition to the rutile phase with a high density of defects. Moreover, we provide important information on the nucleation, growth, and crystallization processes during synthesis, highlighting the impact of Fe atoms incorporation on the TiO2 lattice, the formation of reaction intermediates, and the structural evolution at the nano regime. The ability to control oxygen vacancies and engineer defects in Fe-doped TiO2 opens new possibilities for optimizing charge transport, enhancing catalytic activity, and tuning optical properties for applications in environmental remediation, sensing, and next-generation semiconductor technologies.

The direct synthesis of amorphous metal–organic frameworks (aMOFs) is an appealing yet often avoided approach due to the perceived unpredictability of amorphous network formation. In this study, we develop a strategy for aMOF synthesis using pre-formed nanoclusters and rigid organic linkers, providing enhanced control over disorder and defect chemistry while bypassing the traditional ‘crystallise–amorphise’ approach. By systematically comparing this nanocluster-based method to other direct synthesis routes and using X-ray pair distribution function, thermogravimetric and statistical analyses, we establish key design principles governing aMOF formation. We demonstrate that kinetic control—fast reactions under basic conditions at room temperature—suppresses crystallisation and drives amorphous network formation. Using nanoclusters as synthetic precursors consistently yields highly disordered frameworks with the shortest coherence lengths among direct synthesis methods. Additionally, we show that tuning metal composition through doping with kinetically inert cations restricts coordination reversibility, significantly increasing defect density and structural disorder. Structural analysis reveals that while aMOFs share motifs with crystalline polymorphs, they cannot be directly mapped onto known structures, highlighting the importance for more nuanced characterisation approaches. Just as crystal engineering was instrumental in the expansion of crystalline MOFs, new synthetic strategies are essential for advancing the aMOF field. By developing a systematic approach to aMOF design, this work provides a foundation for tailoring structural disorder and functional properties, expanding the potential of aMOFs for catalysis, adsorption, and transport applications.