1. Department of Chemistry, School of Science, University of Waikato, Hamilton, New Zealand;
2. Current Address: Institute of Environmental Science and Research (ESR), Wellington, New Zealand;
3. School of Chemical Sciences, University of Auckland, Auckland, New Zealand. Current Address: Research School of Chemistry, Australian National University, Canberra, ACT, Australia;
4. School of Fundamental Sciences, Massey University, Palmerston North, New Zealand