1. Departments of Chemistry and Earth & Ocean Sciences, University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada V6T 1Z1, Department of Chemistry, Rhodes University, Grahamstown, South Africa, Institute for Systematics and Ecology, University of Amsterdam, 1090 GT Amsterdam, The Netherlands, and Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada V6T 1Z3