1. Contribution from the Department of Chemistry, The University of Auckland, Private Bag 92019, Auckland, New Zealand, Molecular Photoscience Group, Istituto per la Sintesi Organica e la Fotoreattività (ISOF), Consiglio Nazionale delle Ricerche (CNR), Via Gobetti 101, 40129 Bologna, Italy, and Department of Chemistry, University of California, Riverside, California 92521