1. Department of Chemistry; University of Alberta; Edmonton; Alberta; T6G 2G2; Canada
2. X-ray Crystallography Laboratory, Department of Chemistry; University of Alberta; Edmonton; Alberta; T6G 2G2; Canada
3. Institut de Chimie; Université de Strasbourg; 1 Rue Blaise Pascal; F-67070; Strasbourg; France
4. Department of Chemistry; The University of Texas at El Paso; El Paso; TX; 79968; USA
5. Institut für Organische Chemie; Friedrich-Alexander Universität Erlangen Nürnberg; Henkestraße 42; 91054; Erlangen; Germany