1. Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
2. Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA
3. Center for Innovative Technology, Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, USA
4. Agilent Technologies Inc., Santa Clara, California 95051, USA