Flexible Metal-Organic Frameworks with Isomerizing Building Units

摘要

The utilization of isomerizing building units for constructing flexible metal-organic frameworks is discussed as a prospective strategy for creating new supramolecular materials. The utilization of reversible and controllable structural changes, performed on a molecular level, is a powerful but still not well explored instrument for triggering changes in the bulk properties of supramolecular solids. Such changes include changing the shape or geometry of molecules that can isomerize or oligomerize, and the set of target response properties may involve microporosity in all its diversity as well as other types of functionality. Our recent developments, traced in more detail below, include: (1) The first smart sorbent, the microporosity of which may be generated in situ and reversibly under external control, is represented by a system of two conjugated forms of a copper p-diketonate. (2) The design of new isomerizable host molecules, which are versatile host receptors when in the trans form but incapable of inclusion when in cis form, is represented by the now emerging modified metal dibenzoylmethanates.