1. Noyes Laboratory 210, 127-72, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, Polymer, Ceramics, and Technical Services Laboratories, Tyco Electronics Corporation, Technology Group, 306 Constitution Drive, Menlo Park, California 94025, Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, and Beckman Institute, California Institute of Technology, Pasadena, California 91125