Department of Chemical Engineering, Stanford University, Stanford, California 94305-5025, IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120-6001, Center for New Directions in Organic Synthesis, Department of Chemistry, University of California, Berkeley, California 94720-1460, and Center on Polymer Interfaces and Macromolecular Assemblies, IBM Almaden Research Center, San Jose, California 95120 (At 2005-09-23)