Just as all modern machines are constructed from parts, future atomically precise nanoscale machines will be constructed from an enormous number of nanoscale parts. Ideally, these nanoscale parts will be single molecules containing between 100 to 1,000 atoms to allow them to be large enough and complex enough to carry out designed functions. They will need to be designed on computers, and rapidly synthesized and purified in useful quantities prior to incorporation into a larger structure. We have developed a general approach to the design and synthesis of functionalized nanoscale molecules that has all of the above properties. Our approach involves the synthesis of stereochemically pure cyclic bis-amino acid molecular building blocks that are coupled through pairs of amide bonds to create spiro-linked oligomers of specific constitution. The oligomers are efficiently assembled on solid support using peptide synthesis techniques to first create a flexible oligomer that is then rigidified by the simultaneous formation of a second set of amide bonds between each adjacent pair of monomers. The structure of the resulting spiro-linked oligomers is controlled by the sequence and stereochemistry of the component monomers. The oligomer structures made accessible by this technology range from extended molecular rods to compact structures containing small-molecule sized cavities. We have written a software package that enables anyone to construct oligomer sequences with designed structures, either interactively or through automated computer searches of sequence space. Most of the oligomers that we have synthesized are soluble in aqueous solution, making them easy to handle and compatible with bioactivity studies. This presentation will describe the synthesis of several monomers, their assembly into functionalized spiro-linked oligomers and their structural characterization .
 Christopher G. Levins and Christian E. Schafmeister, "The Synthesis of
Functionalized Nanoscale Molecular Rods of Defined Length" Journal of the American Chemical Society, 125, (2003), 4703-4704