Two types of pseudopolymorphs, 1·(2)3 and 1·(2)2, were obtained from Pd(II) complex (1) with mesitylene (2), and the quantitative transformation into 1·(2)2 from 1·(2)3 was observed over 6 h after shaking for approximately 10 s. The transformation was observed in both a mesitylene-rich solution and under powder conditions. The guest release processes of 1·(2)3 and 1·(2)2 occurred in hexane to yield 1, and the guest insertion processes occurred in 2 to reproduce 1·(2)3 and 1·(2)2, whereas each crystal was constructed from the discrete molecules of each type. These crystals also selectively and repeatedly encapsulated three benzenes or one toluene in the uniform cavities of 1·(2)3 and 1·(2)2. In contrast, the corresponding nonfluorinated derivative, [Pd(dbm)2] (dbm = dibenzoylmetanide), shows no guest encapsulation phenomena, indicating that the remarkable guest encapsulations are induced by fluorine substitutions. The dynamic crystal transformation and the reversible guest encapsulations of the two pseudopolymorphs were investigated by X-ray crystallographic and thermogravimetric studies for both single crystals and powder species.
ASJC Scopus subject areas
- 化学 (全般)