Metal-organic frameworks have found many applications concerning the adsorption of small molecules, 1 but work incorporating other properties, such as electronic conduction, still lags behind. Here, we report a new microporous framework, Cu[Ni(pdt) 2 ] (pdt 2-= pyrazine-2,3-dithiolate), that exhibits electronic conductivity, doping, and redox behavior. Although a number of extended coordination solids with conductivity have been reported, 2 to the best of our knowledge none have been demonstrated to display porosity at the same time. In general, porous, high-surface area materials with electronic conductivity are rare. Combining the porosity and customizability of metalorganic frameworks with electronic conductivity should open up a range of new applications for these materials. Further, in view of the well-studied redox flexibility and strong metal-ligand orbital interactions found within molecular transition metal dithiolene complexes, 3 the extension of this chemistry to metal-organic frameworks provides a promising strategy for achieving electronic conductivity.The compound Cu[Ni(pdt) 2 ] was synthesized using a procedure analogous to that previously described for

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 < or =1 nm, with a significant fraction existing as Ag(3) 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.

Metal−organic frameworks (MOFs) offer an attractive alternative to traditional hard and soft templates for nanocluster synthesis because their ordered crystalline lattice provides a highly controlled and inherently understandable environment. We demonstrate that MOFs are stable hosts for metal hydrides proposed for hydrogen storage and their reactive precursors, providing platform to test recent theoretical predictions that some of these materials can be destabilized with respect to hydrogen desorption by reducing their critical dimension to the nanoscale. With the MOF HKUST-1 as template, we show that NaAlH4 nanoclusters as small as eight formula units can be synthesized. The confinement of these clusters within the MOF pores dramatically accelerates the desorption kinetics, causing decomposition to occur at ∼100 °C lower than bulk NaAlH4. However, using simultaneous thermogravimetric modulated beam mass spectrometry, we also show that the thermal decomposition mechanism of NaAlH4 is complex and may involve processes such as nucleation and growth in addition to the normally assumed two-step chemical decomposition reactions.

Photoluminescence (PL) spectroscopy was used to characterize nanoscale ZnO impurities, amine-donor charge-transfer exciplexes, and framework decomposition in samples of MOF-5 prepared by various methods. The combined results cast doubt on previous reports describing MOF-5 as a semiconductor and demonstrate that PL as a tool for characterizing MOF purity possesses advantages such as simplicity, speed, and sensitivity over currently employed powder XRD MOF characterization methods.

Iron oxide (γ-Fe 2 O 3 ) and cobalt ferrite (Co x Fe 3Àx O 4 ) thin films were synthesized via atomic layer deposition (ALD) on high surface-area (50 m 2 g À1 ) m-ZrO 2 supports. The oxide films were grown by sequentially depositing iron oxide and cobalt oxide, adjusting the number of iron oxide to cobalt oxide cycles to achieve a desired stoichiometry. High resolution transmission electron microscopy and X-ray diffraction indicate that the films are crystalline and have a thickness of ∼2.5 nm. Raman spectroscopy was used to confirm the predominance of the spinel phase in the case of cobalt ferrite. Films were chemically reduced at 600 °C using mixtures of H 2 , CO, and CO 2 . The evolution of oxide phases as a function of time during this reduction was observed using in situ X-ray diffraction, showing that γ-Fe 2 O 3 are reduced only to FeO, while Co x Fe 3Àx O 4 are reduced all the way to a Co/Fe alloy. Subsequent water splitting measurements in a stagnation flow reactor yielded peak H 2 rates exceeding virtually all of those reported in the literature. Co 0.85 Fe 2.15 O 4 films were successfully cycled without deactivation and produced four times more H 2 than γ-Fe 2 O 3 films principally because of the deeper chemical reduction possible. Together, these results suggest a path to robust materials for chemical looping cycles and thermal gas splitting. They also indicate that ALD films can serve as an effective platform for probing the surface chemistry of these processes, since they maintain their reactivity at these temperatures, in contrast with oxide powders that are deactivated by sintering and grain growth.