The preparation of crystalline, ordered thin films of metal-organic frameworks (MOFs) will be a critical process for MOF-based nanodevices in the future. MOF thin films with perfect orientation and excellent crystallinity were formed with novel nanosheet-structured components, Cu-TCPP [TCPP = 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin], by a new "modular assembly" strategy. The modular assembly process involves two steps: a "modularization" step is used to synthesize highly crystalline "modules" with a nanosized structure that can be conveniently assembled into a thin film in the following "assembly" step. With this method, MOF thin films can easily be set up on different substrates at very high speed with controllable thickness. This new approach also enabled us to prepare highly oriented crystalline thin films of MOFs that cannot be prepared in thin-film form by traditional techniques.

The electrical properties of a highly oriented crystalline MOF nanofilm were studied. This nanofilm has low activation energy and a proton conductivity that is among the highest value reported for MOF materials. The study uncovered the reasons for the excellent performance of this nanofilm and revealed a new pathway for proton transport in MOF materials; besides the channels inside a MOF, the surface of the MOF nanocrystal can also dominate proton transport.

The fabrication of porous coordination frameworks in thin-film forms has been investigated intensively with a view to using their structural response to external stimuli and guests for potential nanotechnological applications, for example as membranes for gas separation. Here we report a coordination framework that exhibits a dynamic guest-sorption behaviour in a nanometre-sized thin-film form (16 nm thick), yet shows no guest uptake in the bulk. Highly oriented crystalline thin films of this coordination framework--which consists of interdigitated two-dimensional layers of {Fe(py)2[Pt(CN)4]} (py, pyridine)--were fabricated through liquid-phase layer-by-layer synthesis. The resulting thin film exhibited a clear guest uptake with a structural transformation of the gate-opening type as characterized by in situ X-ray diffraction. Increasing the film's thickness markedly suppressed this behaviour. We envisage that such a crystal-downsizing effect may be observed with other coordination frameworks, and may be of use to develop functional materials, for example, for switching or sensing devices.

We report the fabrication and characterization of the first example of a tetracyanonickelate-based two-dimensional-layered metal-organic framework, {Fe(py)Ni(CN)} (py = pyridine), thin film. To fabricate a nanometer-sized thin film, we utilized the layer-by-layer method, whereby a substrate was alternately soaked in solutions of the structural components. Surface X-ray studies revealed that the fabricated film was crystalline with well-controlled growth directions both parallel and perpendicular to the substrate. In addition, lattice parameter analysis indicated that the crystal system is found to be close to higher symmetry by being downsized to a thin film.

Benzoquinone derivatives, which undergo reversible two-electron redox reactions, should afford high capacity as positive electrode materials for rechargeable batteries. Although some benzoquinones have been reported as cathode active materials, their low cycle-life performance is a drawback. We prepared benzoquinones bearing alkyl groups with various degrees of bulkiness to investigate the relationship between the steric effects of the substituents on the benzoquinone skeleton and the battery performance. The introduction of bulky substituents, especially a tert-butyl group, on the skeleton significantly improved the cyclability.