1. Department of Chemistry, 315 South 1400 East, Room 2124, University of Utah, Salt Lake City, Utah 84112-0850, and
2. Current address: Department of Chemistry Education, Kyungpook National University, Daegu, 702-701, Republic of Korea.
3. Department of Chemistry and Biochemistry, 631 Sumter Street, University of South Carolina, Columbia, South Carolina 29208.