Higher Order Construction of Molecule-Based Magnets

Although template-directed methods of materials synthesis are now becoming commonplace, little attention has been paid to the higher order construction of molecule-based inorganic materials such as transition metal coordination polymers. The preparation of inverse opals of a molecule-based magnet, cobalt hexacyanoferrate, has been achieved by iterations of a reaction cycle that results in the in-filling of colloidal crystals consisting of polystyrene or silica microspheres. Removal of the template produces inverse opals that consist of a periodic array of 100-nm-wide voids enclosed by a coordination polymer framework with 5−10-nm-thick crystalline walls (figure to the right). Such structures offer a potential route to improving the photoinduced magnetization of molecule-based magnets such as cobalt hexacyanoferrate.