Crystallographic direct observation of chemical reactions in a pore

In-situ preparation of labile compounds in a single crystalline state is a unique and effective method for the crystallographic observation. There are, however, several practical problems in this method. Here we utilize the pores of a coordination network. Thanks to the pseudo-solution sate in the pores, even bulky substrates can easily interpenetrate into the crystals with keeping single crystallinity. We examined the reaction of acetaldehyde with amines to form acetaldehyde imines that are, normally, easily hydrolyzed or isomerized into enamines. The aromatic amines were incorporated in the columnar array of aromatic ligands of an as-synthesized porous network complex. We also succeeded in observing several condensation reactions of the aromatic amines to produce acylated products in a pore. (author)