1. Department of Chemistry and Biochemistry University of Denver Denver CO 80208 USA
2. School of Chemistry Chemical Engineering and Biotechnology Nanyang Technological University 21 Nanyang Link Singapore 637371 Singapore
3. Advanced Chemistry Development Inc. (ACD/Labs) Toronto ON M5 C 1B5 Canada
4. School of Chemistry and Molecular Biosciences University of Queensland Brisbane 4072 Queensland Australia