Remarkable Lattice Shrinkage in Highly Oriented Crystalline\nThree-Dimensional Metal–Organic Framework Thin Films

Abstract

Highly oriented crystalline thin\nfilms of metal–organic frameworks (MOFs) have promising practical\napplications, such as in gas separation, catalysis, and sensing. We\nreport on the successful fabrication of highly oriented crystalline\nthin films of three-dimensional porous MOFs, Fe­(pz)­[M­(CN)₄] (M = Ni, Pd; pz = pyrazine). Synchrotron X-ray diffraction studies\nreveal not only the highly oriented crystalline nature but also the\nremarkable shrunken structure of the thin films (∼3–7%\nvolume shrinkage) compared with bulk samples. Furthermore, because\nof lattice shrinkage, these films exhibit large lattice expansions\nupon guest adsorption, in marked contrast to the almost unchanged\nlattice in the bulk samples.