Guest-Induced Flexibility in a Multifunctional Ruthenium-Based Metal-Organic Framework

We present a new example of rare metal-organic frameworks (MOFs) containing ruthenium inorganic building units (IBUs). Advanced characterization techniques such as three-dimensional electron diffraction and in situ powder X-ray diffraction, performed in parallel with adsorption of various gases and vapors, were used to determine the structure and framework dynamics of [Ru-2(bzpdc)(bipy)] (bzpdc = 4,4 '-benzophenone dicarboxylate, bipy = 4,4 '-bipyridine), revealing unique and highly relevant material features: In the 2D nanoporous framework, ruthenium paddle-wheel IBUs are mixed-valent and provide potential open metal sites. Coupled with the flexible behavior of the framework in the form of specific reversible structural transformations and selective gating upon adsorption of various guests, the material is thus ideally suited for sensing or catalytic applications.