Microporous and mesoporous inorganic materials form the backbone of many heterogeneous catalysts and separations media. Because of the incredible commercial potential of these classes of materials, substantial efforts on the part of both academic and industrial researchers have been unleashed to unravel the hidden secrets of the mechanisms of their formation and, through the exploitation of this understanding, to synthesize novel materials with new and important properties. Much of the mechanistic work has focused on understanding the role of organic synthesisdirecting agents, which play a complex, cooperative role in the spatial ordering of inorganic building-blocks through the filling of void space, the balancing charge, and the stabilization of specific structural units.
Recent synthetic work from the laboratories of Prof. Geoffrey Ozid'] and Prof. Stephen Man#] has greatly extended these ideas of cooperative spatial ordering of inorganic-organic assemblies into the realm of macroscopic hierarchical materials. Not only do these new methods and materials have potential in the traditional fields of application such as heterogeneous catalysis, as well as advanced materials technologies, but the growing mechanistic understanding is leading to the generation of materials with striking resemblance to the highly complex forms characteristic of inorganic biological structures. It is the biomimetic implications of these materials that may, ultimately, prove their worth.
In this context, Ozin and his group at the University of Toronto have made remarkable progress in the area of selfassembling ultrastructures and hierarchical inorganic materials. ['] In particular, they have begun to develop the skill of synthesizing and characterizing hierarchical inorganic assemblies that resemble complete biomineralized skeletal structures, all in a beaker. This is an accomplishment that is