Direct Synthesis of Amorphous Metal–Organic Frameworks from Nanoclusters

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.