1. Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
2. Advanced Chemistry Development Inc. (ACD/Laboratories), Toronto, Ontario, Canada M5C 1B5
3. School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
4. School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland 4072, Australia