Motion of an Isolated Water Molecule within a Flexible Coordination Cage: Structural Properties and Catalytic Effects of Ionic Palladium(II) Complexes

The unique cage complexes [[(Me4en)Pd]3(L)2](X)6 (L = 1,3,5-tris(isonicotinoyloxyethyl)cyanurate; X− = BF4−, ClO4−) were constructed. A single water molecule in a skeletal cage was reversibly associated and dissociated via a combination of the adequate space, polar environment, and conformational flexibility of the cage. In Suzuki−Miyaura C−C cross-coupling reactions, the cage complex showed significant catalytic activity along with the effects of the isolated single water molecule.