10.1021/nl901397k.s009 Ronald J. T. Houk Ronald J. T. Houk Benjamin W. Jacobs Benjamin W. Jacobs Farid El Gabaly Farid El Gabaly Noel N. Chang Noel N. Chang A. Alec Talin A. Alec Talin Dennis D. Graham Dennis D. Graham Stephen D. House Stephen D. House Ian M. Robertson Ian M. Robertson Mark D. Allendorf Mark D. Allendorf Silver Cluster Formation, Dynamics, and Chemistry in Metal−Organic Frameworks American Chemical Society 2009 uniform arrays Ag 3 clusters silver nanocluster formation uniform pore sizes particle sizes metal nanoparticles representative MOF templates chemical stabilization Silver Cluster Formation MOF pores 2009-10-14 00:00:00 Media https://acs.figshare.com/articles/media/Silver_Cluster_Formation_Dynamics_and_Chemistry_in_Metal_Organic_Frameworks/2821864 Synthetic methods used to produce metal nanoparticles typically lead to a distribution of particle sizes. In addition, creation of the smallest clusters, with sizes of a few to tens of atoms, remains very challenging. Nanoporous metal−organic frameworks (MOFs) are a promising solution to these problems, since their long-range crystalline order creates completely uniform pore sizes with the potential for both steric and chemical stabilization. We report a systematic investigation of silver nanocluster formation within MOFs using three representative MOF templates. The as-synthesized clusters are spectroscopically consistent with dimensions ≤1 nm, with a significant fraction existing as Ag<sub>3</sub> clusters, as shown by electron paramagnetic resonance. Importantly, we show conclusively that very rapid TEM-induced MOF degradation leads to agglomeration and stable, easily imaged particles, explaining prior reports of particles larger than MOF pores. These results solve an important riddle concerning MOF-based templates and suggest that heterostructures composed of highly uniform arrays of nanoparticles within MOFs are feasible.