1. Bernal Institute Department of Chemical Sciences University of Limerick Limerick V94 T9PX Republic of Ireland
2. School of Chemical Engineering and Light Industry Guangdong University of Technology Guangzhou 510006 P.R. China
3. Department of Chemistry University of South Florida 4202 East Fowler Avenue, CHE205 Tampa Florida 33620-5250 USA
4. Department of Chemistry City University of Hong Kong 83 Tat Chee Avenue Kowloon, Hong Kong P.R. China