25 April 1997
Vol 276, Issue 5312

About The Cover

The synthesis of organic materials with tailored properties requires designs that allow predictable modification of the structure. Host lattices, synthesized from two-dimensional hydrogen-bonded networks (red, white, and blue) linked by molecular pillars (gray and white), trap guest molecules (center) in continuous nanometer-scale channels. The size and chemical nature of the channels can be adjusted systematically by changing the structure of the pillars. See 575 and the related Perspective on 543. [Image: J. Sedgewick]